*Harald Pasch SASOL Chair of Analytical Polymer ScienceDepartment of Chemistry and Polymer Science, University of Stellenbosch, South AfricaAdvanced Fractionation Techniques for Complex Polyolefins

*Polyolefin AnalysisComplex StructuresNew CopolymersNew ApplicationsFractionation Techniques ?HT-SECTREFCRYSTAFChemical compositionMolecularsize

*Polyolefins The Most Common PolymerspolyethylenepolypropyleneWhere are the problems ?

*Narrower PDI (Metallocene)Broader PDI (Ziegler-Natta)Polyolefins just CH, CH2 and CH3 .... ?????Isotactic polypropylene (high crystallinity)Syndiotactic polypropyleneAtactic polypropylene (low crystallinity)

*Polyolefins just CH, CH2 and CH3 .... ?????

1Molecular structure MM,MMDSCB distribution SCB contentInstrumentation requiredHT-SEC CRYSTAF, TREF DSCNMR, FTIR

2MorphologyCrystal size, crystal size distribution tie molecules interfacial orderInstrumentation required

DSC, DMANMR, Microscopy AFM, SEM

3Physical Propertieshaze,gloss, clarity, tear strength, tensile strength,impact strengthInstrumentation required

Different test equipment

*Branch type influences the crystal structure

Distribution of the branches ???Why does chain structure influence properties?

*Results: SEMChange in Crystal Morphology as a Result of BlendingLDPE60% LDPE + 40% Plastomer poly(ethylene-1-octene)

*Molar Mass Analysis

*High-Temperature SEC Polymer Labs Model PL GPC 220Stationary phase: Cross-linked PS

Mobile phase:Trichlorobenzene

Temperature:140 oC

Calibration: PS, PE

Detectors:RI, ELSD, IR, LS, Vis

*HT-SEC and FTIR of an Oxidized Polyethylene?

*Universal LC-FTIR Coupling FTIR spectrometerseries of spectrapump +injectorRI-detectorHPLC / GPCSeparationIdentification

*SEC-FTIR of an Ethylene-Methacrylic Acid Copolymer

*SEC-FTIR Analysis of a Polyolefin Blend

*Separation by Crystallizability: Chemical HeterogeneityTemperature Rising Elution Fractionation (TREF)Crystallization Analysis Fractionation (CRYSTAF) separation with regard to chemical compositionHT-SECCRYSTAFTREF

*Based on Flory-Huggins expression for polymer-diluent mixtures

diluent: solvent, comonomer

melting point depression is a function of non-crystallizable comonomer content

chemical composition separation = separation by crystallizabilitySeparation by Crystallizability: Chemical Heterogeneity

*Temperature Rising Elution Fractionation

*The slow cooling rate is the most important factor in achieving good separation The slow cooling rate minimizes the effects of co-crystallization and molar mass influences.Typical cooling rates would be about 2C/hourIt takes about 2-3 days to cool!!TREF Separation Mechanism

*Comparison of typical LLDPE and LDPETemperature Rising Elution Fractionation

*Hypothetical samples with same MMD and crystallinity distribution but different dependency on each distributionTemperature Rising Elution Fractionation

*Automatic Cross-Fractionation System TREF-SEC S. Nakano, Y. Goto, J. Appl. Polym. Sci. 26 (1981) 4217Temperature Rising Elution Fractionation

*TREF-SEC Analysis of a Blend of Two Polyethylenes S. Nakano, Y. Goto, J. Appl. Polym. Sci. 26 (1981) 4217Temperature Rising Elution Fractionation

*IR detector20304050607080900246Temperature [C]dW/dT dW/dT020406080100W [%] W [%]Crystallization Analysis Fractionation

*Crystallization Analysis Fractionation

*Crystallization Analysis FractionationTypical temperature cycleTypical crystallization curve

*Crystallization Analysis FractionationComparison of TREF and CRYSTAFCrystaf analysis of a PP blend

*CRYSTAF: Analysis of Copolymers and Blends HDPEHDPE/LDPE 4:96HDPE/PP 50 : 50LLDPE

*Propene--Olefin CopolymersPropene-OctenePropene-OctadeceneCRYSTAF: Analysis of Copolymers and Blends

Diagramm1

66.40.470.470.470.47

63.70.570.570.570.57

58.90.860.860.860.86

50.81.271.271.271.27

41.31.731.731.731.73

34.92.892.892.892.89

0.4263.40.420.420.42

0.4765.90.470.470.47

0.7258.30.720.720.72

1.0757.11.071.071.07

1.39491.391.391.39

2.3138.72.312.312.31

2.3937.22.392.392.39

0.260.2665.80.260.26

0.50.559.40.50.5

0.630.6357.70.630.63

0.680.6855.20.680.68

0.890.8951.50.890.89

0.470.470.4761.40.47

0.510.510.5162.90.51

0.660.660.66590.66

0.810.810.8155.50.81

1.091.091.0950.61.09

1.491.491.49451.49

000075.8

Octene

Decene

Tetradecene

Octadecene

PP

% Comonomer

Crystallization Temperature

Propene-Olefin Copolymers

Tabelle1

Comonomer (%)OcteneDeceneTetradeceneOctadecenePP

0.4766.4

0.5763.7

0.8658.9

1.2750.8

1.7341.3

2.8934.9

0.4263.4

0.4765.9

0.7258.3

1.0757.1

1.3949

2.3138.7

2.3937.2

0.2665.8

0.559.4

0.6357.7

0.6855.2

0.8951.5

0.4761.4

0.5162.9

0.6659

0.8155.5

1.0950.6

1.4945

075.8

Tabelle1

Octene

Decene

Tetradecene

Octadecene

PP

% Comonomer

Crystallization Temperature

Propene-Olefin Copolymers

Tabelle2

Tabelle3

*CRYSTAF (in particular when coupled to IR sensor)excellent technique but very time consumingFast and selective techniques are requiredliquid chromatography is a good candidatePolyolefins are soluble only at high temperaturesunconventional stationary and mobile phases ???

*Elution Behaviour of Polyolefins in High Temperature Chromatography (HT-HPLC) Using Interactive Stationary Phases polyolefin must dissolve in the mobile phase screening of solubility polyolefin must interact with the phase system screening of mobile and stationary phases

*Solvents and ColumnsDecalineTrichlorobenzeneCyclohexanoneDimethylformamide

normal phase systems: SiO2 (ZrO2, TiO2, Al2O3)

reversed phase systems:

DiolCNPhenylC8 C18 polarity

polarity

*Screening of Stationary Phases for HT-HPLCStationary phase:dimethylsiloxane-modified silica gel Benzylalcohol

x Cyclohexylacetate

DMF

Cyclohexanone

*Stationary phase: dimethylsiloxane-modified silica gel, solvent: TCBmobile phase: EGMBELimiting conditions with regard to PE ()SEC conditions with regard to PP ()Screening of Stationary Phases for HT-HPLC

*Stationary phase: dimethylsiloxane-modified silica gel, solvent: TCBmobile phase: EGMBEPP 36k + PE 34kPP 57k + PE 66kPP 438k + PE 500kPP: SECPE: Limiting conditionsScreening of Stationary Phases for HT-HPLC

*Analysis of PE-PMMA Block Copolymers: SEC and FTIRMultimodal distributionblend or copolymer ?MMA and ethylene units can be identified, but is it a copolymer or a polymer blend ?PEPMMAChemical composition as a function of molar mass ??

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Detector Signal (mV)

1x10

3

1x10

4

1x10

5

1x10

6

1x10

7

T 1

T 8

T 9

T 11

Molar Mass (g/mol)

717.52

758.78

840.50

955.22

993.31

1148.34

1191.54

1000

y

3000

1728.98

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

2000

4000

Wavenumbers (cm-1)

*Chemical composition as a function of molar mass is visualized !

Homopolymers and copolymers can be identified !PEPMMAPEPE-b-PMMAAnalysis of PE-PMMA Block Copolymers: Coupled SEC-FTIR

*What about interaction chromatography ?SECLC-CCmolar mass separationchemical composition separationAnalysis of PE-PMMA Block Copolymers

*PEPMMAPE-b-PMMA

Column: Nucleosil 300 C18 Temperature: 140C Mobile phase: gradient from100 % DMF to 100 % TCB

Analysis of PE-PMMA Block Copolymers: Gradient HPLC

*PEPMMAPE-b-PMMA---- PMMA 1730 cm-1----- PE 720 cm-1High-Temperature Gradient HPLC as a New Tool for the Analysis of Olefin CopolymersAnalysis of PE-PMMA Block Copolymers: Gradient HPLC-FTIR

*Polymer Labs High-Temperature Gradient HPLC System

*Separation System for PE-PP BlendsTime [min] signal% TCBPPMPE

*Separation System for PE-PP Blendscolumn: Nucleosil 500mobile phase: EGMBE-TCBT: 140oCdetector: ELSDsample solvent: TCB PPPEEP copolymer with 48% ethylene ethylene-richpropylene-richPPL.-C. Heinz, H. Pasch, High-Temperature Gradient HPLC for the Separation of Polyethylene-Polypropylene Blends.Polymer 46 (2005) 12040

*Separation System for EVA Copolymersstationary phase: silica gel mobile phase: gradient of decaline-cyclohexanonePVAcPEA. Albrecht, R. Brll, T. Macko, H. Pasch: Separation of Ethylene-Vinyl Acetate Copolymers by High-Temperature Gradient Liquid Chromatography. Macromolecules 40 (2007) 5545

*Separation of Polyolefins by Tacticitystationary phase: carbon-based mobile phase: gradient of 1-decanol-TCB

*Schematic Protocol for 2D Separations

_944201697.unknown

*

Degasser

Pump

Degasser

Pump

Injector

HPLC ColumnTwo-Dimensional Chromatography (HPLC vs. SEC)DetectorWaste1. Dimension:HPLC/LCCC2. Dimension:GPCSEC Column

*High-Temperature 2D-HPLC in Stellenbosch

*Chromatographic conditions:Stationary phase: HypercarbMobile phase: gradient of decanol-TCBOperating temperature: 160 oCHigh-Temperature 2D-HPLCGinsburg, A., Macko, T., Dolle, V., Bruell, R., Europ. Polym. J. 47 (2011) 319-329

*High-Temperature LC-NMR

*HTStop-flowvalveELSDTransferlineTransferlineHT-SECHigh-Temperature LC-NMR

*polyethylenepolymethyl methacrylatecopolymer EtMMA

*On-flow High-Temperature SEC-NMRTCBImpuritiesT=130C

*PEMn=1.100Et-MMAMn=10.600PMMAMn=263.000Solvent subtraction of impuritiesT=130Cflow rate 0.5mL/min, conc. 2+2+2 mg/mL, 300 L injection volume, 5 Waters columns, 24 scans per FID, 1.24s repetition delay On-flow High-Temperature SEC-NMR

*1H traces of the on-flow runOn-flow High-Temperature SEC-NMR

*on-flow HT-SEC-NMR of PE-PMMA Block CopolymerEMMAOn-flow High-Temperature SEC-NMR

*******Eine Kopplung kann in der sogenannten zweidimensionalen Chromatographie erfolgen. Das Herzstck der Anlage ist ein 8-Port-Schaltventil, ber das zwei Probenschleifen abwechselnd befllt werden knnen.In der ersten Dimension wird meistens eine HPLC-Methode eingesetzt. Dabei wird eine konzentrierte Probe wird auf die HPLC-Sule aufgegeben. Mit einer sehr kleinen Flurate wird das Eluat direkt in die erste Probenschleife gefllt. Wenn dies geschehen ist, schaltet das Ventil, so da nun die zweite Schleife befllt werden kann.Gleichzeitig wird der Inhalt der ersten Schleife automatisch in die sogenannte zweite Dimension - meistens eine Grenausschluchromatographie, injiziert.Um auf diese Weise zu jedem Punkt der ersten Dimension eine entsprechende Molmassenverteilung zu erhalten, mu gewhrleistet sein, da die GPC fr den nchsten Injekt bereit ist, sobald die nchste Schleife gefllt ist. Dies erfordert eine sorgfltige Abstimmung der Fluraten in der ersten und der zweiten Dimension.