Thermal Degradation of Thermal Degradation of Polymethyl methacrylatePolymethyl methacrylate

MSc Uumlmit TAYFUNMSc Uumlmit TAYFUN

CHEM 512 DEGRADATION AND STABILIZATION OF POLYMERSCHEM 512 DEGRADATION AND STABILIZATION OF POLYMERS

METU 2007

Poly(methyl methacrylate)

PMMA is the mostPMMA is the most important important commercial polymer of the acrylic commercial polymer of the acrylic classclass

It is an amorphous linear polymer It is an amorphous linear polymer valued forvalued for its hardness rigidity its hardness rigidity transparency and weatheringtransparency and weathering resistanceresistance

Glazing applications exploit good Glazing applications exploit good impact resistance and dull shards impact resistance and dull shards formed upon fractureformed upon fracture

Applications of PMMAMajor applications of PMMA includeMajor applications of PMMA include

Automotive industry - rear lamps light Automotive industry - rear lamps light fixturesfixtures

Acrylic sheet - bathtubsAcrylic sheet - bathtubs

Glazing ndash signsGlazing ndash signs

Composites - sinks basins and bathroom Composites - sinks basins and bathroom fixturesfixtures

CContact lenses bone cementsontact lenses bone cements

MMembrane for dialysis embrane for dialysis

DDental restorationsental restorations

Road LinesRoad Lines

Degradation Degradation

At high temperatures the components of the long At high temperatures the components of the long chain backbone of the polymer can begin to separate chain backbone of the polymer can begin to separate (molecular scission) and react with one another to (molecular scission) and react with one another to change the properties of the polymer It is part of a change the properties of the polymer It is part of a larger group of degradation mechanisms for larger group of degradation mechanisms for polymers that can occur from a variety of causes polymers that can occur from a variety of causes such as such as Heat (thermal degradation and thermal oxidative Heat (thermal degradation and thermal oxidative degradation when in the presence of oxygen) degradation when in the presence of oxygen) Light (photodegradation) Light (photodegradation) Oxygen (oxidative degradation) Oxygen (oxidative degradation) Weathering (generally UV degradation) Weathering (generally UV degradation)

Thermal Degradation Thermal Degradation

The chemical reactions involved in thermal The chemical reactions involved in thermal degradation lead to physical and optical property degradation lead to physical and optical property changes relative to the initially specified changes relative to the initially specified properties Thermal degradation generally properties Thermal degradation generally involves changes to the molecular weight of the involves changes to the molecular weight of the polymer and typical property changes include polymer and typical property changes include

1048707 1048707 Reduced ductility and embrittlement Reduced ductility and embrittlement 1048707 1048707 Chalking Chalking 1048707 1048707 Color changes Color changes 1048707 1048707 Cracking Cracking

Thermal DegradationThermal Degradation

Many reactions occur in the polymer thermal Many reactions occur in the polymer thermal degradation as show belowdegradation as show below

mainchain scission

side group scission

disappear

depolymerization

Thermal Degradation of PMMAThermal Degradation of PMMA

At high temperature polymers such as poly(methyl methacrylate) At high temperature polymers such as poly(methyl methacrylate) become thermally unstable leading to degradation by become thermally unstable leading to degradation by depolymerization to yield a mixture of monomer and polymerdepolymerization to yield a mixture of monomer and polymer

PMMA depolymerization is favoured at 300degC External sources of PMMA depolymerization is favoured at 300degC External sources of radicals and defects in chemical structure make the material more radicals and defects in chemical structure make the material more susceptible to this mode of degradationsusceptible to this mode of degradation

Radical initiation isRadical initiation is thermolytic leading to thermolytic leading to fragmentation of tertiaryfragmentation of tertiaryradicals to yieldsradicals to yieldsmonomer and equivalentmonomer and equivalenttertiary radicaltertiary radical

PMMA

Homolytic bond dissociation

Tertiary alkyl radical

Secondary alkyl radicalfragmentation

Thermal degradation of PMMA at 300-4OOThermal degradation of PMMA at 300-4OOdegdegC is the chain C is the chain radical reaction of depolymerization The main volatile radical reaction of depolymerization The main volatile product of this process is MMA Initiation of PMMA product of this process is MMA Initiation of PMMA depolymerization proceeds via statistic rupture of depolymerization proceeds via statistic rupture of macromolecule with formation of two free macroradicals and macromolecule with formation of two free macroradicals and via disruption of the link which is near the end double bond via disruption of the link which is near the end double bond with formation of an active macroradical and a relatively with formation of an active macroradical and a relatively stable allyl radical stable allyl radical

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Poly(methyl methacrylate)

PMMA is the mostPMMA is the most important important commercial polymer of the acrylic commercial polymer of the acrylic classclass

It is an amorphous linear polymer It is an amorphous linear polymer valued forvalued for its hardness rigidity its hardness rigidity transparency and weatheringtransparency and weathering resistanceresistance

Glazing applications exploit good Glazing applications exploit good impact resistance and dull shards impact resistance and dull shards formed upon fractureformed upon fracture

Applications of PMMAMajor applications of PMMA includeMajor applications of PMMA include

Automotive industry - rear lamps light Automotive industry - rear lamps light fixturesfixtures

Acrylic sheet - bathtubsAcrylic sheet - bathtubs

Glazing ndash signsGlazing ndash signs

Composites - sinks basins and bathroom Composites - sinks basins and bathroom fixturesfixtures

CContact lenses bone cementsontact lenses bone cements

MMembrane for dialysis embrane for dialysis

DDental restorationsental restorations

Road LinesRoad Lines

Degradation Degradation

At high temperatures the components of the long At high temperatures the components of the long chain backbone of the polymer can begin to separate chain backbone of the polymer can begin to separate (molecular scission) and react with one another to (molecular scission) and react with one another to change the properties of the polymer It is part of a change the properties of the polymer It is part of a larger group of degradation mechanisms for larger group of degradation mechanisms for polymers that can occur from a variety of causes polymers that can occur from a variety of causes such as such as Heat (thermal degradation and thermal oxidative Heat (thermal degradation and thermal oxidative degradation when in the presence of oxygen) degradation when in the presence of oxygen) Light (photodegradation) Light (photodegradation) Oxygen (oxidative degradation) Oxygen (oxidative degradation) Weathering (generally UV degradation) Weathering (generally UV degradation)

Thermal Degradation Thermal Degradation

The chemical reactions involved in thermal The chemical reactions involved in thermal degradation lead to physical and optical property degradation lead to physical and optical property changes relative to the initially specified changes relative to the initially specified properties Thermal degradation generally properties Thermal degradation generally involves changes to the molecular weight of the involves changes to the molecular weight of the polymer and typical property changes include polymer and typical property changes include

1048707 1048707 Reduced ductility and embrittlement Reduced ductility and embrittlement 1048707 1048707 Chalking Chalking 1048707 1048707 Color changes Color changes 1048707 1048707 Cracking Cracking

Thermal DegradationThermal Degradation

Many reactions occur in the polymer thermal Many reactions occur in the polymer thermal degradation as show belowdegradation as show below

mainchain scission

side group scission

disappear

depolymerization

Thermal Degradation of PMMAThermal Degradation of PMMA

At high temperature polymers such as poly(methyl methacrylate) At high temperature polymers such as poly(methyl methacrylate) become thermally unstable leading to degradation by become thermally unstable leading to degradation by depolymerization to yield a mixture of monomer and polymerdepolymerization to yield a mixture of monomer and polymer

PMMA depolymerization is favoured at 300degC External sources of PMMA depolymerization is favoured at 300degC External sources of radicals and defects in chemical structure make the material more radicals and defects in chemical structure make the material more susceptible to this mode of degradationsusceptible to this mode of degradation

Radical initiation isRadical initiation is thermolytic leading to thermolytic leading to fragmentation of tertiaryfragmentation of tertiaryradicals to yieldsradicals to yieldsmonomer and equivalentmonomer and equivalenttertiary radicaltertiary radical

PMMA

Homolytic bond dissociation

Tertiary alkyl radical

Secondary alkyl radicalfragmentation

Thermal degradation of PMMA at 300-4OOThermal degradation of PMMA at 300-4OOdegdegC is the chain C is the chain radical reaction of depolymerization The main volatile radical reaction of depolymerization The main volatile product of this process is MMA Initiation of PMMA product of this process is MMA Initiation of PMMA depolymerization proceeds via statistic rupture of depolymerization proceeds via statistic rupture of macromolecule with formation of two free macroradicals and macromolecule with formation of two free macroradicals and via disruption of the link which is near the end double bond via disruption of the link which is near the end double bond with formation of an active macroradical and a relatively with formation of an active macroradical and a relatively stable allyl radical stable allyl radical

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Applications of PMMAMajor applications of PMMA includeMajor applications of PMMA include

Automotive industry - rear lamps light Automotive industry - rear lamps light fixturesfixtures

Acrylic sheet - bathtubsAcrylic sheet - bathtubs

Glazing ndash signsGlazing ndash signs

Composites - sinks basins and bathroom Composites - sinks basins and bathroom fixturesfixtures

CContact lenses bone cementsontact lenses bone cements

MMembrane for dialysis embrane for dialysis

DDental restorationsental restorations

Road LinesRoad Lines

Degradation Degradation

At high temperatures the components of the long At high temperatures the components of the long chain backbone of the polymer can begin to separate chain backbone of the polymer can begin to separate (molecular scission) and react with one another to (molecular scission) and react with one another to change the properties of the polymer It is part of a change the properties of the polymer It is part of a larger group of degradation mechanisms for larger group of degradation mechanisms for polymers that can occur from a variety of causes polymers that can occur from a variety of causes such as such as Heat (thermal degradation and thermal oxidative Heat (thermal degradation and thermal oxidative degradation when in the presence of oxygen) degradation when in the presence of oxygen) Light (photodegradation) Light (photodegradation) Oxygen (oxidative degradation) Oxygen (oxidative degradation) Weathering (generally UV degradation) Weathering (generally UV degradation)

Thermal Degradation Thermal Degradation

The chemical reactions involved in thermal The chemical reactions involved in thermal degradation lead to physical and optical property degradation lead to physical and optical property changes relative to the initially specified changes relative to the initially specified properties Thermal degradation generally properties Thermal degradation generally involves changes to the molecular weight of the involves changes to the molecular weight of the polymer and typical property changes include polymer and typical property changes include

1048707 1048707 Reduced ductility and embrittlement Reduced ductility and embrittlement 1048707 1048707 Chalking Chalking 1048707 1048707 Color changes Color changes 1048707 1048707 Cracking Cracking

Thermal DegradationThermal Degradation

Many reactions occur in the polymer thermal Many reactions occur in the polymer thermal degradation as show belowdegradation as show below

mainchain scission

side group scission

disappear

depolymerization

Thermal Degradation of PMMAThermal Degradation of PMMA

At high temperature polymers such as poly(methyl methacrylate) At high temperature polymers such as poly(methyl methacrylate) become thermally unstable leading to degradation by become thermally unstable leading to degradation by depolymerization to yield a mixture of monomer and polymerdepolymerization to yield a mixture of monomer and polymer

PMMA depolymerization is favoured at 300degC External sources of PMMA depolymerization is favoured at 300degC External sources of radicals and defects in chemical structure make the material more radicals and defects in chemical structure make the material more susceptible to this mode of degradationsusceptible to this mode of degradation

Radical initiation isRadical initiation is thermolytic leading to thermolytic leading to fragmentation of tertiaryfragmentation of tertiaryradicals to yieldsradicals to yieldsmonomer and equivalentmonomer and equivalenttertiary radicaltertiary radical

PMMA

Homolytic bond dissociation

Tertiary alkyl radical

Secondary alkyl radicalfragmentation

Thermal degradation of PMMA at 300-4OOThermal degradation of PMMA at 300-4OOdegdegC is the chain C is the chain radical reaction of depolymerization The main volatile radical reaction of depolymerization The main volatile product of this process is MMA Initiation of PMMA product of this process is MMA Initiation of PMMA depolymerization proceeds via statistic rupture of depolymerization proceeds via statistic rupture of macromolecule with formation of two free macroradicals and macromolecule with formation of two free macroradicals and via disruption of the link which is near the end double bond via disruption of the link which is near the end double bond with formation of an active macroradical and a relatively with formation of an active macroradical and a relatively stable allyl radical stable allyl radical

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Degradation Degradation

At high temperatures the components of the long At high temperatures the components of the long chain backbone of the polymer can begin to separate chain backbone of the polymer can begin to separate (molecular scission) and react with one another to (molecular scission) and react with one another to change the properties of the polymer It is part of a change the properties of the polymer It is part of a larger group of degradation mechanisms for larger group of degradation mechanisms for polymers that can occur from a variety of causes polymers that can occur from a variety of causes such as such as Heat (thermal degradation and thermal oxidative Heat (thermal degradation and thermal oxidative degradation when in the presence of oxygen) degradation when in the presence of oxygen) Light (photodegradation) Light (photodegradation) Oxygen (oxidative degradation) Oxygen (oxidative degradation) Weathering (generally UV degradation) Weathering (generally UV degradation)

Thermal Degradation Thermal Degradation

The chemical reactions involved in thermal The chemical reactions involved in thermal degradation lead to physical and optical property degradation lead to physical and optical property changes relative to the initially specified changes relative to the initially specified properties Thermal degradation generally properties Thermal degradation generally involves changes to the molecular weight of the involves changes to the molecular weight of the polymer and typical property changes include polymer and typical property changes include

1048707 1048707 Reduced ductility and embrittlement Reduced ductility and embrittlement 1048707 1048707 Chalking Chalking 1048707 1048707 Color changes Color changes 1048707 1048707 Cracking Cracking

Thermal DegradationThermal Degradation

Many reactions occur in the polymer thermal Many reactions occur in the polymer thermal degradation as show belowdegradation as show below

mainchain scission

side group scission

disappear

depolymerization

Thermal Degradation of PMMAThermal Degradation of PMMA

At high temperature polymers such as poly(methyl methacrylate) At high temperature polymers such as poly(methyl methacrylate) become thermally unstable leading to degradation by become thermally unstable leading to degradation by depolymerization to yield a mixture of monomer and polymerdepolymerization to yield a mixture of monomer and polymer

PMMA depolymerization is favoured at 300degC External sources of PMMA depolymerization is favoured at 300degC External sources of radicals and defects in chemical structure make the material more radicals and defects in chemical structure make the material more susceptible to this mode of degradationsusceptible to this mode of degradation

Radical initiation isRadical initiation is thermolytic leading to thermolytic leading to fragmentation of tertiaryfragmentation of tertiaryradicals to yieldsradicals to yieldsmonomer and equivalentmonomer and equivalenttertiary radicaltertiary radical

PMMA

Homolytic bond dissociation

Tertiary alkyl radical

Secondary alkyl radicalfragmentation

Thermal degradation of PMMA at 300-4OOThermal degradation of PMMA at 300-4OOdegdegC is the chain C is the chain radical reaction of depolymerization The main volatile radical reaction of depolymerization The main volatile product of this process is MMA Initiation of PMMA product of this process is MMA Initiation of PMMA depolymerization proceeds via statistic rupture of depolymerization proceeds via statistic rupture of macromolecule with formation of two free macroradicals and macromolecule with formation of two free macroradicals and via disruption of the link which is near the end double bond via disruption of the link which is near the end double bond with formation of an active macroradical and a relatively with formation of an active macroradical and a relatively stable allyl radical stable allyl radical

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal Degradation Thermal Degradation

The chemical reactions involved in thermal The chemical reactions involved in thermal degradation lead to physical and optical property degradation lead to physical and optical property changes relative to the initially specified changes relative to the initially specified properties Thermal degradation generally properties Thermal degradation generally involves changes to the molecular weight of the involves changes to the molecular weight of the polymer and typical property changes include polymer and typical property changes include

1048707 1048707 Reduced ductility and embrittlement Reduced ductility and embrittlement 1048707 1048707 Chalking Chalking 1048707 1048707 Color changes Color changes 1048707 1048707 Cracking Cracking

Thermal DegradationThermal Degradation

Many reactions occur in the polymer thermal Many reactions occur in the polymer thermal degradation as show belowdegradation as show below

mainchain scission

side group scission

disappear

depolymerization

Thermal Degradation of PMMAThermal Degradation of PMMA

At high temperature polymers such as poly(methyl methacrylate) At high temperature polymers such as poly(methyl methacrylate) become thermally unstable leading to degradation by become thermally unstable leading to degradation by depolymerization to yield a mixture of monomer and polymerdepolymerization to yield a mixture of monomer and polymer

PMMA depolymerization is favoured at 300degC External sources of PMMA depolymerization is favoured at 300degC External sources of radicals and defects in chemical structure make the material more radicals and defects in chemical structure make the material more susceptible to this mode of degradationsusceptible to this mode of degradation

Radical initiation isRadical initiation is thermolytic leading to thermolytic leading to fragmentation of tertiaryfragmentation of tertiaryradicals to yieldsradicals to yieldsmonomer and equivalentmonomer and equivalenttertiary radicaltertiary radical

PMMA

Homolytic bond dissociation

Tertiary alkyl radical

Secondary alkyl radicalfragmentation

Thermal degradation of PMMA at 300-4OOThermal degradation of PMMA at 300-4OOdegdegC is the chain C is the chain radical reaction of depolymerization The main volatile radical reaction of depolymerization The main volatile product of this process is MMA Initiation of PMMA product of this process is MMA Initiation of PMMA depolymerization proceeds via statistic rupture of depolymerization proceeds via statistic rupture of macromolecule with formation of two free macroradicals and macromolecule with formation of two free macroradicals and via disruption of the link which is near the end double bond via disruption of the link which is near the end double bond with formation of an active macroradical and a relatively with formation of an active macroradical and a relatively stable allyl radical stable allyl radical

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal DegradationThermal Degradation

Many reactions occur in the polymer thermal Many reactions occur in the polymer thermal degradation as show belowdegradation as show below

mainchain scission

side group scission

disappear

depolymerization

Thermal Degradation of PMMAThermal Degradation of PMMA

At high temperature polymers such as poly(methyl methacrylate) At high temperature polymers such as poly(methyl methacrylate) become thermally unstable leading to degradation by become thermally unstable leading to degradation by depolymerization to yield a mixture of monomer and polymerdepolymerization to yield a mixture of monomer and polymer

PMMA depolymerization is favoured at 300degC External sources of PMMA depolymerization is favoured at 300degC External sources of radicals and defects in chemical structure make the material more radicals and defects in chemical structure make the material more susceptible to this mode of degradationsusceptible to this mode of degradation

Radical initiation isRadical initiation is thermolytic leading to thermolytic leading to fragmentation of tertiaryfragmentation of tertiaryradicals to yieldsradicals to yieldsmonomer and equivalentmonomer and equivalenttertiary radicaltertiary radical

PMMA

Homolytic bond dissociation

Tertiary alkyl radical

Secondary alkyl radicalfragmentation

Thermal degradation of PMMA at 300-4OOThermal degradation of PMMA at 300-4OOdegdegC is the chain C is the chain radical reaction of depolymerization The main volatile radical reaction of depolymerization The main volatile product of this process is MMA Initiation of PMMA product of this process is MMA Initiation of PMMA depolymerization proceeds via statistic rupture of depolymerization proceeds via statistic rupture of macromolecule with formation of two free macroradicals and macromolecule with formation of two free macroradicals and via disruption of the link which is near the end double bond via disruption of the link which is near the end double bond with formation of an active macroradical and a relatively with formation of an active macroradical and a relatively stable allyl radical stable allyl radical

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal Degradation of PMMAThermal Degradation of PMMA

At high temperature polymers such as poly(methyl methacrylate) At high temperature polymers such as poly(methyl methacrylate) become thermally unstable leading to degradation by become thermally unstable leading to degradation by depolymerization to yield a mixture of monomer and polymerdepolymerization to yield a mixture of monomer and polymer

PMMA depolymerization is favoured at 300degC External sources of PMMA depolymerization is favoured at 300degC External sources of radicals and defects in chemical structure make the material more radicals and defects in chemical structure make the material more susceptible to this mode of degradationsusceptible to this mode of degradation

Radical initiation isRadical initiation is thermolytic leading to thermolytic leading to fragmentation of tertiaryfragmentation of tertiaryradicals to yieldsradicals to yieldsmonomer and equivalentmonomer and equivalenttertiary radicaltertiary radical

PMMA

Homolytic bond dissociation

Tertiary alkyl radical

Secondary alkyl radicalfragmentation

Thermal degradation of PMMA at 300-4OOThermal degradation of PMMA at 300-4OOdegdegC is the chain C is the chain radical reaction of depolymerization The main volatile radical reaction of depolymerization The main volatile product of this process is MMA Initiation of PMMA product of this process is MMA Initiation of PMMA depolymerization proceeds via statistic rupture of depolymerization proceeds via statistic rupture of macromolecule with formation of two free macroradicals and macromolecule with formation of two free macroradicals and via disruption of the link which is near the end double bond via disruption of the link which is near the end double bond with formation of an active macroradical and a relatively with formation of an active macroradical and a relatively stable allyl radical stable allyl radical

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal degradation of PMMA at 300-4OOThermal degradation of PMMA at 300-4OOdegdegC is the chain C is the chain radical reaction of depolymerization The main volatile radical reaction of depolymerization The main volatile product of this process is MMA Initiation of PMMA product of this process is MMA Initiation of PMMA depolymerization proceeds via statistic rupture of depolymerization proceeds via statistic rupture of macromolecule with formation of two free macroradicals and macromolecule with formation of two free macroradicals and via disruption of the link which is near the end double bond via disruption of the link which is near the end double bond with formation of an active macroradical and a relatively with formation of an active macroradical and a relatively stable allyl radical stable allyl radical

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal Degradation of PMMAThermal Degradation of PMMA

There are two There are two degradationdegradation reactions for PMMA reactions for PMMA

lsquolsquofast reaction which is chain-end initiated due to fast reaction which is chain-end initiated due to double-bonded chain-end polymer molecules double-bonded chain-end polymer molecules

slow reaction which is initiated at random slow reaction which is initiated at random

The energy of activation for the fast The energy of activation for the fast reaction is much smaller than that of the reaction is much smaller than that of the slow reactionslow reaction

DegradationDegradation of isotactic and syndiotactic of isotactic and syndiotactic PMMAPMMA which degrade by random initiation which degrade by random initiation have a first-order termination reactionhave a first-order termination reaction

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

PMMA is regarded as a polymer that depropagates to PMMA is regarded as a polymer that depropagates to monomer as a result of thermal degradation up to 550monomer as a result of thermal degradation up to 550degdegC C

PMMA degrades predominantly by a depropagation process PMMA degrades predominantly by a depropagation process (as a reverse of the polymerisation process) the rate of (as a reverse of the polymerisation process) the rate of which is first-order in weight loss which is first-order in weight loss

At lower degradation temperatures (340ndash361At lower degradation temperatures (340ndash361degdegC) the C) the mechanism of thermal degradation was initiated by a mechanism of thermal degradation was initiated by a mixture of chain end and chain scission processes followed mixture of chain end and chain scission processes followed by depropagation by depropagation

At higher temperatures initiation was by a mixture of chain At higher temperatures initiation was by a mixture of chain end and chain scission processes followed by end and chain scission processes followed by depropagation to the end of the polymer chain depropagation to the end of the polymer chain

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal Degradation of PMMAThermal Degradation of PMMA

PMMA produces char The PMMA produces char The process appears to be elimination process appears to be elimination of the methoxycarbonyl side-of the methoxycarbonyl side-group producing an unsaturated group producing an unsaturated conjugated system The amount conjugated system The amount of char yielded varies with of char yielded varies with molecular weight and molecular weight and temperature and in some cases temperature and in some cases it is estimated that 15 of the it is estimated that 15 of the PMMA structure can degrade in PMMA structure can degrade in this way this way

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal Degradation of PMMAThermal Degradation of PMMA

The degradation of PMMA is a radical chain The degradation of PMMA is a radical chain reaction that occurs in three irreversible stepsreaction that occurs in three irreversible steps

InitiationInitiation PMMA degrades randomly into two PMMA degrades randomly into two radicals by breakage of the bond in the radicals by breakage of the bond in the positionposition

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal Degradation of PMMAThermal Degradation of PMMA

DepropagationDepropagation

The depropagation step consists of the production The depropagation step consists of the production of the monomer from the newly created radicals of the monomer from the newly created radicals

This is the reverse of the propagation step in the polymerization process

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal Degradation of PMMAThermal Degradation of PMMA

TerminationTermination

The termination occurs by interaction of the pair of The termination occurs by interaction of the pair of radicals to reform a polymer radicals to reform a polymer

This model with the stationary-state assumption for This model with the stationary-state assumption for all radical concentrations leads to a rate equation all radical concentrations leads to a rate equation that is first-order in polymer concentration that is first-order in polymer concentration

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

Thermal Thermal Stabilization of PMMAStabilization of PMMA

Non-crosslinking sucrose-Non-crosslinking sucrose-based additivesbased additives

Sucrose-based crosslinkers Sucrose-based crosslinkers and additives and additives

PSPS

Polysulfide polymers like poly Polysulfide polymers like poly styrene disulfide (PSD) and styrene disulfide (PSD) and polystyrene tetrasulfide (PST) polystyrene tetrasulfide (PST)

Fullerene C[60] Fullerene C[60]

Thermal stability of PMMA increases with addingThermal stability of PMMA increases with adding

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309

ReferencesReferences KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo KPielichowski JNjuguna lsquorsquoThermalDegradation of Polymeric Materialsrsquorsquo Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Technical White Paper lsquorsquoThermal Degradation of Plasticslsquorsquo Zeus Industrial Products Inc 2005 Products Inc 2005 JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of JellinekHHG lsquorsquoThermal Degradation of Polymethylmethacrylate Energies of Activationrsquorsquo Jan 1968Activationrsquorsquo Jan 1968BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of BJ Holland JN Hay ldquoThe kinetics and mechanisms of the thermal degradation of poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared poly(methyl methacrylate) studied by thermal analysis-Fourier transform infrared spectroscopyrdquo Polymer 42 (2001) 4825ndash4835spectroscopyrdquo Polymer 42 (2001) 4825ndash4835Grassie N and Scott G lsquorsquoPolymer Degradation and StabilizationrsquorsquoGrassie N and Scott G lsquorsquoPolymer Degradation and Stabilizationrsquorsquo Cambridge Cambridge University Press Cambridge 1985University Press Cambridge 1985Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Nobuyuki Higashi Hideki Shiba and Masazo Niwardquo Thermal Degradation of Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules Poly(methyl methacrylate) Polymer with Head-to-HeadLinkagesrdquo Macromolecules 1989 22 4652-46541989 22 4652-4654 Grassie N Scott G Grassie N Scott G Polymer Degradation and StabilisationPolymer Degradation and Stabilisation

Cambridge University Press London 1985Cambridge University Press London 19858 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N 8 Kannah Ganesh Ramakrıshnan Lathan Kaushal Kıshore Benny George K N Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Ninan ldquoStabilization of Thermal Degradation of Poly(methylmethacrylate) by Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 Polysulfide Polymersrdquo Journal of Applied Polymer Science Vol 66 2149ndash2156 (1997)(1997)Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl Giridhar Madras J M Smith and Benjamin J McCoyrdquo Degradation of Poly(methyl methacrylate) in Solutionrdquo methacrylate) in Solutionrdquo Ind Eng Chem Res Ind Eng Chem Res 1996 1996 35 35 1795-18001795-1800Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Lewis E Manring ldquoThermal Degradation of Poly(methy1 methacrylate) 4 Random Side-Group Scissionrdquo Macromolecules 199124 3304-3309Side-Group Scissionrdquo Macromolecules 199124 3304-3309