Post on 13-Jun-2018
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Performance improvement and innovation: the role of nanotechnologiesEnrico BoccaleriAssociate Professor, Ph.D. Università del Piemonte Orientale - ITALY
CONTENT
1. Nanomaterials: an introduction
2. Experimental plan for PVC nanocomposites for cables
3. Thermal behaviour of PVC nanocomposites for cables
4. Stabilisation and HCl evolution
5. Perspectives & Conclusions
3 TITLE
Nanomaterials at a glance
Filler dimensions:Macro mmMicro µmNano nm
Form factor:3D Particles (nano-oxides, POSS)
2D Nanotubes
1D Layered materials (clays, hydroxides and hydrotalcites, phosphates, phosphonates)
4 TITLE
Materials in this work
Layered hydroxides• Cost effective• Can develop high surface area• Can be tailored in the properties• Can deliver manifold features to PVC
Clay-based materials• Cost effective for natural systems,
expensive if fully synthetic• Can develop high surface area• Can be tailored in the properties• Mainly developed/used in other
matrices than PVC
5 TITLE
Materials in this work
• POSS are actual 3D nanostructured hybrid materials• General formula (RSiO1.5)n
• Each Si atom is bound to:• One and a half atoms of Oxygen (sesquioss-)• An organic group (-ane)
Compatibilità organica e diminuzione viscosità
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6 TITLE
Materials in this workOpen cage systems
with high reactivity with surfaces and materials
Metal-containing materialsfor distributed catalytically
active sites
7 TITLE
How this stuff works…?
• Organic-inorganic hybrids : chemical approach
• Nanocomposites: physical approach
Dispersion of nanostructured particles in an organicmatrix (i.e. polymer), based on chemical affinity andinterfacial interactions between the two phases
Covalently bound structures interacting at molecularlevel (co-polymer, grafting, reactive processing)
8 TITLE
Going to nano scale….
• “bulk” effects dominate the final properties• Modeling of the features refer to mean material
properties• Interfacial effects are quite negligible• The final properties of a compound is described
by the sum of the features of the components
“Macro” fillers in polymers• Dispersion issues• Influence of mechanical features• Optical properties (i.e. reduction of
transparency, haze, gloss…)• Aesthetic features• Durability• Processing issues (loading, flow, melt
strength….)• Weight increase• Barrier effect• Physical aspects
Why???
9 TITLE
Going to nano scale….“Macro” fillers in polymers
• Final properties are related to effectsoperating at nanoscale level
• Surface and interfacial effects are crucial• The final properties are not related to the
basic features of the components but to the capability and type of interactions they give
• Surface/volume and surface/mass ratio are relevant
• Dispersion issues• Influence of mechanical features• Optical properties (i.e. reduction of
transparency, haze, gloss…)• Aesthetic features• Durability• Processing issues (loading, flow, melt
strength….)• Weight increase• Barrier effect• Physical aspects
“Nano” fillers in polymers
10 TITLE
Experimental plan for PVC cables
General purposes:
- Use of commercial grade matrices (cable-grade PVC formulation)
- Use of market-ready nanoadditives (no lab scale quantities)
- Use of industrial(-like) equipment for polymer treatment
- Afford the maximum performances vs. additive concentration (0.3 to 10 phr)
- Avoid umpairing other features (i.e. processability, flow etc….)
- Evaluate synergistic effects among nanostructured additives
- Use the experimental results to create background knowledge and understanding
11 TITLE
Experimental plan for PVC cables
Dry blending
NanofillersConcentrations rangingbetween 0.3 to 2.5 phr
PVC for cablesDry Blend
Extrusion
PVC K.70 phr 100
Coated CaCO3 (AtomforS) phr 75
DINP non stab. phr 50
Chloroparaffins (52%) phr 18
Calcium Stearate phr 1,5
Zinc Stearate phr 0,4
Soybeans oil epox phr 4
Realube RL105 phr 0,7
Stearic Acid phr 0,3
Irganox 1010 phr 0,2
Sb2O3 phr 4
+
Fireproof insulators
Twin screw co-rotating extruder• TM 20 HT – Maris• L/D = 40•D/d ratio = 1,55• Screw prof. = 3,5 mm• Output: pellet 4 mm• Air coolling• Feed rate: 3-7 kg/h
• XRD• TGA• SEM• Density• MFI• Color – LAB• Mechanical prop.• Hardness• Thermal stability (80°C - 7gg)• Xn test (250 e 500 h)• HCl evolution• Fire behaviour: UL94/LOI
Characterisation
12 TITLE
Thermal behaviour (TGA)
POSS presence modifies the thermal behaviour of the materials:- Delay of the degradation onset (chemical effect)- Modification of the degradation profiles (stabilisation
of labile sites)Different nanoadditives give a different effect
T = 50-800°C 10°C/min – Ar flow
REFERENCEPOSS1 0,62POSS2 0,62POSS3 0,62POSS4 0,62
13 TITLE
Thermal behaviour (TGA)
A synergistic role of POSS can be highlighted, globally reducing and delaying the decomposition and HClevolution
A nanoadditive (0,31 to 1,25 phr) can modify the degradation of PVC especiallyafter the onset of the first degradation
T = 50-800°C 10°C/min – Ar flow
ReferenceInorg (0,31)Inorg (0,31)/POSS1 (0,62)
ReferenceInorg (0,31)/POSS1 (0,62)Inorg (0,62)/POSS1 (0,62)Inorg (1,25)/POSS1 (0,62)
14 TITLE
Thermal behaviour (TGA)
The synergy of POSS with layered materials results in evident changes involving:-labile sites stabilisation- HCl scavenging- Condensed phase catalysis
T = 50-800°C 10°C/min – Ar flow
ReferenceHTLC (5)/POSS1 (0,62)HTLC (5)/POSS3 (0,62)Clay (2,5)/POSS A (0,62)
The decomposition profile is deeply modified in:• The onset of the degradation• The amount of weight loss• The temperature of occurence of degradation• The kinetics of degradation
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What says the literature…..Attività espletate - Analisi termica TGA e meccanismo di degradazione
The preliminary decomposition of PVC is due to “labile sites” thatcan be generated during processing, recycling or use that break producing HCl and give rise, at higher temperature, to an avalanche effect (secondary dehydrochlorination).The presence of cross-linking and compact chain domains can reduce this initiation process.
16 TITLE
Thermal stability# MATERIAL Formulation Density Hardness Thermal stability Th. Stab after
80°Cx168 h LOI
ISO 1183 ISO 868 CEI 20-34/3-2 CEI 20-34/3-2 CEI 20-22/4g/ml Sh A 15’’ minutes minutes %
1 REFERENCE 1,479 80,0 40 24,52 Inorganic 0,31 phr 1,480 77,5 40 25,53 Inorganic 0,62 phr 1,481 77,5 45 25,5
4 Inorganic 0,31 phr/POSS 0,62 phr
1,480 77,0 55 25,5
5 Inorganic 0,62 phr/POSS 0,62 phr
1,479 78,0 55 25,0
10 POSS1 0,62 phr 1,472 77,5 45 25,011 POSS2 0,62 phr 1,474 78,0 40 25,512 POSS3 0,62 phr 1,473 81,0 40 25,013 POSS4 0,62 phr 1,470 79,5 60 35 25,5
14 Clay 2,5 phr/POSS1 0,62 phr 1,484 81,0 55 25,0
15 HTLC 5 phr/POSS1 0,62 phr 1,493 80,0 165 140 25,5
16 Inorganic 1,25 phr/POSS1 0,62 phr
1,477 77,0 40 35 25,0
17 HTLC 5 phr/POSS1 0,62 phr 1,486 81,5 165 140 25,5
18 HTLC 5 phr 1,498 82,0 165 140 26,019 HTLC2 1,25 phr 1,484 80,0 40 37 25,0
17 TITLE
Designing new formulations….Sample HCl evolution Variation
%CEI 20-37
mg/gREFERENCE 140HTLC 5 phr 125 -10,7
POSS 0,62 phr 130 -7,1HTLC 5 phr/POSS 0,62
phr 120-14,3
HTLC 5 phr theo 90 -36%HTLC 10 phr theo 40 -72%
modified HTLC 5 phrtheo 92,2
-34%modified HTLC 10 phr
theo 44,4-68%
modified HTLC 5 phr/POSS 0,62 phr theo ≅84
-40%modified HTLC 10
phr/POSS 0,62 phr theo ≅38-73%
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Designing new formulations….Sample HCl evolution Variation
%CEI 20-37
mg/gREFERENCE 140HTLC 5 phr 125 -10,7
POSS 0,62 phr 130 -7,1HTLC 5 phr/POSS 0,62
phr 120-14,3
HTLC 5 phr theo 90 -36%HTLC 10 phr theo 40 -72%
modified HTLC 5 phrtheo 92,2
-34%modified HTLC 10 phr
theo 44,4-68%
modified HTLC 5 phr/POSS 0,62 phr theo ≅84
-40%modified HTLC 10
phr/POSS 0,62 phr theo ≅38-73%
Optimisation of the dispersion can make the difference!!!!
19 TITLE
Designing new formulations….Sample HCl evolution Variation
%CEI 20-37
mg/gREFERENCE 140HTLC 5 phr 125 -10,7
POSS 0,62 phr 130 -7,1HTLC 5 phr/POSS 0,62
phr 120-14,3
HTLC 5 phr theo 90 -36%HTLC 10 phr theo 40 -72%
modified HTLC 5 phrtheo 92,2
-34%modified HTLC 10 phr
theo 44,4-68%
modified HTLC 5 phr/POSS 0,62 phr theo ≅84
-40%modified HTLC 10
phr/POSS 0,62 phr theo ≅38-73%
20 TITLE
Designing new formulations….Sample HCl evolution Variation
%CEI 20-37
mg/gREFERENCE 140HTLC 5 phr 125 -10,7
POSS 0,62 phr 130 -7,1HTLC 5 phr/POSS 0,62
phr 120-14,3
HTLC 5 phr theo 90 -36%HTLC 10 phr theo 40 -72%
modified HTLC 5 phrtheo 92,2
-34%modified HTLC 10 phr
theo 44,4-68%
modified HTLC 5 phr/POSS 0,62 phr theo ≅84
-40%modified HTLC 10
phr/POSS 0,62 phr theo ≅38-73%
These results must be consideredaside the improval of thermalbehaviour performances:
1. Chemical stability (higher Tonset)
2. Thermal decomposition shift
3. HCl evolution shift in temperature
SUMMING UP Despite a restricted number of papers in literature, a
comprehensive study of nanoadditives in PVC demonstrates their suitability for this matrix
Effects at nanoscale level are evident in features asthermal stability, degradation and HCl evolution
Stabilisation involves also the beginning of the degradation process (chemical effect on PVC matrix)
Amount involved can reach quantities lower than 0,5 phr
Synergistic effects can magnify the effects of nanoadditives
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