1 Commodity Thermoplastics_ LDPE, HDPE, PP, PVC, PS Professor Joe Greene CSU, CHICO
Feb 07, 2016
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Commodity Thermoplastics_ LDPE, HDPE, PP, PVC, PS
Professor Joe GreeneCSU, CHICO
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Polyolefin Definition • Olefins: Unsaturated, aliphatic hydrocarbons made from ethylene gas• Ethylene is produced by cracking higher hydrocarbons of natural gas
or petroleum• Olefin means oil forming• Historically given to ethylene because oil was formed when ethylene
was treated with Cl.• Now applies to all hydrocarbons with linear C::C double bonds (not
aromatic C::C double bonds)• Polyethylene discovered around 1900, though using an expensive
process• LDPE commercialized in 1939 • HDPE commercialized in 1957
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Principal Olefin Monomers
• Ethylene Propylene
• Butene-1 4-Methylpentene
C C
H H
H H
C C
C2H5 H
H H
C C
CH3 H
H H
C C
C5H6 H
H H
CH3
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Several Olefin Polymers
• Poly Ethylene Poly Propylene
• PolyisoButene PolyMethylpentene
C C
C2H5 H
H H
n
C C
C5H6 H
H H
CH3
n
C C
H H
H H
n
C C
CH3 H
H H
n
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Polymers Derived from Ethylene Monomer
X Position Material Name AbbreviationH Polyethylene PECl Polyvinyl chloride PVCMethyl group Polypropylene PPBenzene ring Polystyrene PSCN Polyacrylonitrile PANOOCCH3 Polyvinyl acetate PvaCOH Polyvinyl alcohol PVACOOCH3 Polymethyl acrylate PMAF Polyvinyl fluoride PVF
Note:Methyl Group is:
|H – C – H | H
Benzene ring is:
X Position Y Position Material Name AbbreviationF F Polyvinylidene fluoride PVDFCl Cl Polyvinyl dichloride PVDCCH3 (Methyl group) CH3 Polyisobutylene PBCOOCH3 CH3 Polymethyl methacrylate PMMA
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Addition Polymerization of PE• Polyethylene produced with low (Ziegler) or high pressure (ICI) • Polyethylene produced with linear or branched chains
C C
H H
H H
n
C C
H H
H H
C C
H H
H H
C C
H H
H H
C C
H H
H H
OR
C C
H H
H H
n
C C
H H
H H
C C
H
H H
C C
H H
H H
C C
H H
H HC
CHH
HH
n
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Mechanical Properties of Polyethylene• Type 1: (Branched) Low Density of 0.910 - 0.925 g/cc• Type 2: Medium Density of 0.926 - 0.940 g/cc• Type 3: High Density of 0.941 - 0.959 g/cc• Type 4: (Linear) High Density to ultra high density > 0.959
Mechanical PropertiesBranched LowDensity
MediumDensity
HighDensity
Linear High Density
Density 0.91- 0.925 0.926- 0.94 0.941-0.95 0.959-0.965
Crystallinity 30% to 50% 50% to 70% 70% to 80% 80% to 91%
MolecularWeight
10K to 30K 30K to 50K 50K to 250K 250K to 1.5M
TensileStrength, psi
600 - 2,300 1,200 - 3,000 3,100 - 5,500 5,000 – 6,000
TensileModulus, psi
25K – 41K 38K – 75 K 150K – 158K
150K – 158 K
TensileElongation, %
100% - 650% 100%- 965% 10% - 1300% 10% - 1300%
Impact Strengthft-lb/in
No break 1.0 – nobreak
0.4 – 4.0 0.4 – 4.0
Hardness, Shore D44 – D50 D50 – D60 D60 – D70 D66 – D73
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Physical Properties of Polyethylene
Physical Properties of polyethyleneBranched LowDensity
Medium Density HighDensity
Linear High Density
Optical Transparent toopaque
Transparent toopaque
Transparent toopaque
Transparent to opaque
Tmelt 98 – 115 C 122 – 124 C 130 – 137 C 130 –137 C
Tg -100 C -100 C -100 C -100 CH20 Absorption Low < 0.01 Low < 0.01 Low < 0.01 Low < 0.01
OxidationResistance
Low, oxidesreadily
Low, oxidesreadily
Low, oxides readily Low, oxides readily
UV Resistance Low, Crazesreadily
Low, Crazesreadily
Low, Crazes readily Low, Crazes readily
SolventResistance
Resistantbelow 60C
Resistant below60C
Resistant below 60C Resistant below 60C
AlkalineResistance
Resistant Resistant Resistant Resistant
AcidResistance
OxidizingAcids
Oxidizing Acids Oxidizing Acids Oxidizing Acids
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Processing Properties of Polyethylene
Processing Properties
Branched LowDensity
Medium Density HighDensity
Linear High Density
Tmelt 98 – 115 C 122 – 124 C 130 – 137 C 130 –137 C
Recommended TempRange (I:Injection, E:Extrusion)
I: 300F – 450FE: 250F – 450F
I: 300F – 450FE: 250F – 450F
I: 350F – 500FE: 350F – 525F
I: 350F – 500FE: 350F – 525F
Molding Pressure 5 – 15 psi 5 – 15 psi 12 – 15 psi 12– 15 psi
Mold (linear) shrinkage(in/in)
0.015 – 0.050 0.015 – 0.050 0.015 – 0.040 0.015 – 0.040
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Special Low Versions of PolyethyleneProduced through catalyst selection and regulation of reactor conditions
• Very Low Density Polyethylene (VLDPE)– Densities between 0.890 and 0.915– Applications include disposable gloves, shrink packages,
vacuum cleaner hoses, tuning, bottles, shrink wrap, diaper film liners, and other health care products
• Linear Low Density Polyethylene (LLDPE)– Densities between 0.916 and 0.930– Contains little if any branching– Properties include good flex life, low warpage, and improved stress-
crack resistance– Applications include films for ice, trash, garment, and produce bags
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Special High Versions of PolyethyleneProduced through catalyst selection and regulation of reactor conditions
• High Molecular Weight- High Density Polyethylene (HMW-HDPE)– Densities are 0.941 or greater– MW from 200K to 500 K– Properties include improved toughness, chemical resistance,
impact strength, and high abrasion resistance. – High viscosities– Applications include trash liners, grocery bags, industrial pipe,
gas tanks, and shipping containers
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Special High Versions of PolyethyleneProduced through catalyst selection and regulation of reactor conditions
• Ultra High Molecular Weight Polyethylene (UHMWPE)– Densities are 0.96 or greater– MW from 3M to 6M– Properties include improved high wear resistance, chemical inertness,
and low coefficient of friction. – High viscosities result in material not flowing or melting.– Processed similar to PTFE (Teflon)– Ram extrusion and compression molding are used.– Applications include pump parts, seals, surgical implants, pen tips, and
butcher-block cutting surfaces.
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Copolymers of Polyethylene• Ethylene-ethyl acrylate (EEA)
– Properties range from rubbery to tough ethylene-like properties– Applications include hot melt adhesives, shrink wrap, produce bags, bag-
in-box products, and wire coating.• Ethylene-methyl acrylate (EMA)
– Produced by addition of methyl acrylate monomer (40% by weight)with ethylene gas
– Tough, thermally stable olefin with good elastomeric characteristics.– Applications include food packaging, disposable medical gloves, heat-
sealable layers, and coating for composite packaging
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Copolymers of Polyethylene• Ethylene-Vinyl Acetate (EVA)
– Repeating groups is ethylene with an acetate functional– Part of the pendent group are highly polar.– Vinyl acetate reduces crystallinity and increases chemical reactivity because
of high regions of polarity.– Result:flexible polymer that bonds well to other materials– Excellent adhesive (Elmers Glue)– Other applications include flexible packaging, shrink wrap, auto bumper
pads, flexible toys, and tubing
C C
H H
H H
C C
H OC = OC
H H
n m
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Copolymers of Polyethylene• Ethylene-Propylene (EPM)
– Ethylene and propylene are copolymerized in random manner and causes a delay in the crystallization.
– Thus, the copolymer is rubbery at room temp because the Tg is between HDPE (-110C) and PP (-20C).
– Ethylene and propylene can be copolymerized with small amounts of a monomer containing 2 C=C double bonds (dienes)
– Results in a ter polymer, EPDM, or thermoplastic rubber, TPO
C C
H H
H H
n
C C
CH3 H
H H
m
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Mechanical Properties of PE Blends
Mechanical Properties of PE Blends
Ethylene-vinylacetate
Ethylene-vinylalcohol
Ethylene-ethyl acrylate
Ethylene-methylacrylate
Density 0.922 – 0.943 1.14 – 1.19 0.93 0.942 – 0.945
TensileStrength, psi
2,200 – 4,000 8,520 – 11,600 1,600 – 2,100 1,650
TensileModulus, psi
7K – 29K 300 K – 385 K 4K – 7.5 K 12 K
TensileElongation, %
300% - 750% 180%- 280% 700% - 750% 740%
Impact Strengthft-lb/in
No break 1.0 – 1.7 No break
Hardness, Shore D17 – D45 D27 – D38
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Processing Properties of PE Blends
Processing PropertiesEthylene-vinylacetate
Ethylene-vinylalcohol
Ethylene-ethylacrylate
Ethylene-methylacrylate
Tmelt 103 – 108 C 142 – 181 C 83 C
Recommended TempRange (C: Compression) (I:Injection, E:Extrusion)
C: 200-300FI: 300F – 430FE: 300F – 380F
I: 365F – 480FE: 365F – 480F
C: 200 – 300FI: 250F – 500F
E: 300F – 620F
Molding Pressure 1 – 20 psi 1 – 20 psi
Mold (linear) shrinkage(in/in)
0.007 – 0.035 0.015 – 0.035
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Polypropylene History • Prior to 1954 most attempts to produce plastics
from polyolefins had little commercial success• PP invented in 1955 by Italian Scientist F.J.
Natta by addition reaction of propylene gas with a sterospecific catalyst titanium trichloride.
• Isotactic polypropylene was sterospecific (molecules are arranged in a definite order in space)
• Polypropylene is similar in manufacturing method and in properties to PE
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Chemical Structure• Propylene
• Isotactic- CH3 on one side of polymer chain (isolated). Commercial PP is 90% to 95% Isotactic
C C
CH3 H
H H
C C
CH3 H
H H
C C
CH3 H
H H
C C
CH3 H
H H
C C
CH3 H
H H
C C
CH3 H
H H
n
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Polypropylene Stereostatic Arrangements
•Atactic- CH3 in a random order (A- without; Tactic- order) Rubbery and of limited commercial value.
•Syndiotactic- CH3 in a alternating order (Syndio- ; Tactic- order)
C C
CH3 H
H H
C C
H H
H CH3
C C
CH3 H
H H
C C
H H
H CH3
C C
CH3 H
H H
C C
CH3 H
H H
C C
H H
H CH3
C C
H H
H CH3
C C
CH3 H
H H
C C
H H
H CH3
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Addition Polymerization of PP• Polypropylene produced with low pressure process (Ziegler) • Polypropylene produced with linear chains• Polypropylene is similar in manufacturing method and in properties to PE• Differences between PP and PE are
– Density: PP = 0.90; PE = 0.941 to 0.965– Melt Temperature: PP = 176 C; PE = 110 C– Service Temperature: PP has higher service temperature– Hardness: PP is harder, more rigid, and higher brittle point– Stress Cracking: PP is more resistant to environmental stress cracking
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Advantages of Polypropylene• Advantages
– Low Cost– Excellent flexural strength– Good impact strength– Processable by all thermoplastic equipment– Low coefficient of friction– Excellent electrical insulation– Good fatigue resistance– Excellent moisture resistance– Service Temperature to 126 C– Very good chemical resistance
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Disadvantages of Polypropylene
• Disadvantages– High thermal expansion– UV degradation– Poor weathering resistance– Subject to attack by chlorinated solvents and aromatics– Difficulty to bond or paint– Oxidizes readily– flammable
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Molecular Weight Review• Molecular Weight estimates the average length of the polymer chain and is similar to the DP (degree of
polymerization)– MW = (MW of mer) x DP
• Example: MW= 100,000 for PS then the DP = 1000. (PS = 104 amu)• Example: MW= 50,000 for PE then the DP = 1800. (PE = 28 amu)
• Molecular Weight is measured by osmometry, light scattering and solution viscosity• Molecular Weight is characterized by Weight Average, Mw, and Number Average, Mn.• Polydispersity, PD
– Ratio of Mw / Mn
Weight
Frequency
Mw
Mn
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Mechanical Properties of Polypropylene Mechanical Properties of Polypropylene
Polypropylene LDPE(For Comparison)
HDPE(For Comparison)
Density 0.90 0.91- 0.925 0.959-0.965
Crystallinity 30% to 50% 30% to 50% 80% to 91%
Molecular Weight 200K to 600K 10K to 30K 250K to 1.5M
Molecular WeightDispersity MWD(Mw/Mn)
Range ofMWD forprocessing
Range of MWDfor processing
Range of MWDfor processing
Tensile Strength,psi
4,500 – 5,500 600 - 2,300 5,000 – 6,000
Tensile Modulus,psi
165K – 225K 25K – 41K 150K – 158 K
TensileElongation, %
100% - 600% 100% - 650% 10% - 1300%
Impact Strengthft-lb/in
0.4 – 1.2 No break 0.4 – 4.0
Hardness, Shore R80 - 102 D44 – D50 D66 – D73
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Physical Properties of Polyethylene
Physical Properties of Polypropylene
Polypropylene LDPE HDPEOptical Transparent to
opaqueTransparent toopaque
Transparent to opaque
Tmelt 175 C 98 – 115 C 130 –137 C
Tg -20 C -100 C -100 CH20Absorption
0.01 – 0.03 Low < 0.01 Low < 0.01
OxidationResistance
Low, oxidesreadily
Low, oxidesreadily
Low, oxides readily
UV Resistance Low, Crazesreadily
Low, Crazesreadily
Low, Crazes readily
SolventResistance
Resistantbelow 80C
Resistant below60C
Resistant below 60C
AlkalineResistance
Resistant Resistant Resistant
AcidResistance
OxidizingAcids
Oxidizing Acids Oxidizing Acids
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Processing Properties of Polyethylene
Processing PropertiesPolypropylene LDPE HDPE
Tmelt 175 C 98 – 115 C 130 –137 C
Recommended TempRange (I:Injection, E:Extrusion)
I: 400F – 550FE: 400F – 500F
I: 300F – 450FE: 250F – 450F
I: 350F – 500FE: 350F – 525F
Molding Pressure 10 -20 psi 5 – 15 psi 12– 15 psi
Mold (linear) shrinkage(in/in)
0.010 – 0.025 0.015 – 0.050 0.015 – 0.040
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Copolymers of Polypropylene• Ethylene-propylene copolymers
– Small amount of PP can lower crystallinity of linear HDPE• Polyallomers (block copolymers)
– Blocks of PE and PP polymers allows crystallization to take place– Properties are similar to HDPE and PP
• Ethylene-propylene rubbers – Random co-polymerization of ethylene and propylene prevents crystallization of the chains
by suppressing regularity of molecules– Resulting polymers are amorphous having low Tg (between -110C and -20C depending on
% of PE and PP)– Polymers are rubbery at room temperature– Conventional vulcanization allows for use as commercial rubber, thermoplastic rubbers,
TPR
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Polyolefin_Polybutylene
• History
– PB invented in 1974 by Witco Chemical– Ethyl side groups in a linear backbone
• Description– Linear isotactic material– Upon cooling the crystallinity is 30%– Post-forming techniques can increase crystallinity to 55%– Formed by conventional thermoplastic techniques
• Applications (primarily pipe and film areas)– High performance films– Tank liners and pipes– Hot-melt adhesive – Coextruded as moisture barrier and heat-sealable packages
C C
CH2 H
H H
CH3
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Properties of Polybutylene
Mechanical Properties of PolybutylenePolybutylene Polypropylene LDPE
(For Comparison)HDPE(For Comparison)
Density 0.908 -.917 0.90 0.91- 0.925 0.959-0.965
Crystallinity 30% to 50% 30% to 50% 30% to 50% 80% to 91%
Tensile Strength,psi
4,000 4,500 – 5,500 600 - 2,300 5,000 – 6,000
Tensile Modulus,psi
10K – 40K 165K – 225K 25K – 41K 150K – 158 K
TensileElongation, %
300% - 400% 100% - 600% 100% - 650% 10% - 1300%
Impact Strengthft-lb/in
No break 0.4 – 1.2 No break 0.4 – 4.0
Hardness Shore D55 – D65 R80 - 102 D44 – D50 D66 – D73
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Polyolefin_Polymethylpentene (PMP)
• Description– Crystallizes to 40%-60% – Highly transparent with 90% transmission– Formed by injection molding and blow molding
• Properties– Low density of 0.83 g/cc; High transparency – Mechanical properties comparable to polyolefins with higher
temperature properties and higher creep properties.– Low permeability to gasses and better chemical resistance– Attacked by oxidizing agents and light hydrogen carbon solvents– Attacked by UV and is quite flammable
• Applications – Lighting elements (Diffusers, lenses reflectors), liquid level– Food packaging containers, trays, and bags.
C C
CH2 H
H H
H3C-CH-CH3
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Properties of Polymethylpentene
Mechanical Properties of Polymethylpentene
Polymethyl-pentene
Polypropylene LDPE(For Comparison)
HDPE(For Comparison)
Density 0.83 0.90 0.91- 0.925 0.959-0.965
Crystallinity 40% to60% 30% to 50% 30% to 50% 80% to 91%
Tensile Strength,psi
4,000 – 5,000 4,500 – 5,500 600 - 2,300 5,000 – 6,000
Tensile Modulus,psi
160K – 200K 165K – 225K 25K – 41K 150K – 158 K
TensileElongation, %
100% - 400% 100% - 600% 100% - 650% 10% - 1300%
Impact Strengthft-lb/in
0.4 – 1.0 0.4 – 1.2 No break 0.4 – 4.0
Hardness R80 – R100 R80 - 102 D44 – D50 D66 – D73
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PVC Background • Vinyl is a varied group- PVC, PVAc, PVOH, PVDC, PVB
– Polyvinyls were invented in 1835 by French chemist V. Regnault when he discovered a white residue could be synthesized from ethylene dichloride in an alcohol solution. (Sunlight was catalyst)
– PVC was patented in 1933 by BF Goodrich Company in a process that combined a plasticizer, tritolyl phosphate, with PVC compounds making it easily moldable and processed.
– PVC is the leading plastic in Europe and second to PE in the US.– PVC is made by suspension process (82%), by mass polymerization (10% ), or
by emulsion (8%)– All PVC is produced by addition polymerization from the vinyl chloride
monomer in a head-to-tail alignment.– PVC is amorphous with partially crystalline (syndiotactic) due to structural
irregularity increasing with the reaction temperature.– PVC (rigid) decomposes at 212 F leading to dangerous HCl gas
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PVC and Vinyl Products• Rigid-PVC
– Pipe for water delivery– Pipe for structural yard and garden structures
• Plasticizer-PVC or Vinyl– Latex gloves– Latex clothing– Paints and Sealers– Signs
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PVC and PS Chemical Structure• Vinyl Groups (homopolymers produced by addition polymerization)
– PVC - poly vinylidene - polyvinylalcohol (PVOH) chloride (PVDC)
– polyvinyl acetate (PVAc) - PolyStyrene (PS)
C C
H OCOCH3
H H
C C
H Cl
H H
n
C C
H Cl
H Cl
n
n
C C
H OH
H H
n
C C
H
H H
n
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Mechanical Properties of Polyvinyls Mechanical Properties
PVC (rigid) PVC (Flexible) PVB PVDCDensity, g/cc 1.30-1.58 1.16-1.35 1.05 1.65-1.72
Tensile Strength,psi
6,000 - 7,500 1,500 -3,500 500 - 3,000 3,500 - 5,000
Tensile Modulus,psi
350K – 600K 160K –240K
TensileElongation, %
40% - 80% 200%-450% 150% - 450% 160% -240%
Impact Strengthft-lb/in
0.4 - 22 Range Range 0.4 - 1
Hardness Shore D65-85 Shore A50-100 M60-65
CLTE10-6 mm/mm/C
50 -100 70-250 190
HDT 264 psi 140 F -170F 130F -150F
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Physical Properties of Polyvinyls
PVC (rigid) PVC (Flexible) PVB PVDC
Optical Transparent Transparent Transparent Transparent
Tmelt 75 – 105 C 75 – 105 C 49 172C
Tg 75 -105C 75-105C 49 -15C
H20Absorption
0.04-0.4% (24h) 0.15-0.75% (24h) 0.09-0.16% (24h) 0.1% (24h)
OxidationResistance
good good good good
UV Resistance Poor Poor Poor good
SolventResistance
Soluble inAcetone, and
Cyclohexanol.Partially in
Toluene
Soluble inAcetone, and
Cyclohexanol.Partially in
Toluene
Dissolved in ketonesand esters
good
AlkalineResistance
Excellent Excellent Excellent good
AcidResistance
good good good good
Cost $/lb $0.27 $0.27 $ $1.62
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Processing Properties of Polyvinyls
PVC (rigid) PVC (Flexible) PVB PVDCTmelt 75 – 105 C 75 – 105 C 49 172C
Recommended TempRange (I:Injection, E:Extrusion,C: Compression)
I: 300F – 415FC: 285F-400F
I: 320F – 385FC: 285F - 350F
I: 250F – 340FC: 280F-320F
I: 300F – 400FC: 260F-350FE: 300F-400F
Molding Pressure 10-40 kpsi 8-25 kpsi 0.5-3kpsi 5 - 30 kpsi
Mold (linear) shrinkage(in/in)
0.002 – 0.006 0.010 – 0.050 0.005 - 0.025
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PS Background • PS is one of the oldest known vinyl compounds
– PS was produced in 1851 by French chemist M. Berthelot by passing benzene and ethylene through a red-hot-tube (basis for today)
– Amorphous polymer made from addition polymerization of styrene– Homopolymer (crystal): (2.7 M metric tons in 1994)
• Clear and colorless with excellent optical properties and high stiffness.• It is brittle until biaxially oriented when it becomes flexible and durable.
– Graft copolymer or blend with elastomers- Impact polystyrene (IPS): • Tough, white or clear in color, and easily extruded or molded.• Properties are dependent upon the elastomer %, but are grouped into
– medium impact (Izod<1.5 ft-lb), high impact (Izod between 1.5 to 2.4 ft-lb) and super-high impact (Izod between 2.6 and 5 ft-lb)
– Copolymers include SAN (poly styrene-acrylonitrile), SMA (maleic anhydride), SBS (butadiene), styrene and acrylic copolymers.
– Expandable PS (EPS) is very popular for cups and insulation foam. • EPS is made with blowing agents, such as pentane and isopentane. • The properties are dependent upon cell size and cell size distribution
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Mechanical Properties of PS, ABS, SAN
Mechanical PropertiesPS ABS SAN
Density, g/cc 1.04 1.16-1.21 1.07
Tensile Strength,psi
5,000 - 7,200 3,300 - 8,000 10,000 -12,000
Tensile Modulus,psi
330K-475K 320K-400K 475K-560K
TensileElongation, %
1.2% - 2.5% 1.5%-25% 2%-3%
Impact Strengthft-lb/in
0.35-0.45 1.4-12 0.4-0.6
Hardness M60-75 R100-120 R83, M80
CLTE10-6 mm/mm/C
50 -83 65- 95 65-68
HDT 264 psi 169F - 202F 190F - 225F 214F - 220F
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Physical Properties of PS, ABS, SAN
PS ABS SAN
Optical Transparent Transparent Transparent
Tmelt 100 C 125C 120C
Tg 75 -105C 110 -125C 120C
H20Absorption
0.01-0.03% (24h) 0.2-0.6% (24h) 0.15-0.25% (24h)
OxidationResistance
good good good
UV Resistance fair fair fair
SolventResistance
Soluble inAcetone, Benzene,
Toluene andMethylenedichloride
Soluble inToluene and
Ethylenedichloride,Partially inBenzene
Dissolved in ketonesand esters
AlkalineResistance
Excellent Excellent Poor: attacked byoxidizing agents
AcidResistance
Poor: attacked byoxidizing agents
Poor: attacked byoxidizing agents
good
Cost $/lb $0.41 $0.90 $0.87
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Processing Properties of PS, ABS, SAN
PS ABS SANTmelt 100 C 125C 120C
Recommended TempRange (I:Injection, E:Extrusion)
I: 350F – 500FE: 350F- 500FC: 300F - 400F
I: 380F – 500FC: 350F - 500F
I: 360F – 550FE: 360F -450FC:300F - 400F
Molding Pressure 5 - 20 kpsi 8-25 kpsi 5-20 kpsi
Mold (linear) shrinkage(in/in)
0.004 – 0.007 0.004 – 0.008 0.003 – 0.005
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Section Review • Major Topics
– Vinyl is a varied group- PVC, PVAc, PVOH, PVDC, PVB.– PVC is the leading plastic in Europe and second to PE in the US.– PVC is produced by addition polymerization from the vinyl chloride monomer
in a head-to-tail alignment.– PVC is partially crystalline (syndiotactic) with structural irregularity increasing
with the reaction temperature.– PVC (rigid) decomposes at 212 F leading to dangerous HCl gas X1– Vinyls have (CH2CX2) repeating link– PS is Amorphous and made from addition polymerization– PC is amorphous and made from condensation polymerization – Effects of reinforcements on PP and PS
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Homework Questions
6. Four typical Physical Properties of PVC are Optical = _______, Resistance to moisture= ______ , UV resistance= _____, solvent resistance=_______
7. The Advantages of PP are ________, ________, _______, and __________.
8. The Disadvantages of PP are ________, ________, _______, and __________.
9. Glass fiber affects PP by (strength) ________, (modulus)________, (impact)_______, (density) __________, and (cost) ____________.
10. Two Blends PVC are ___________, and __________.
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Section Review • Major Topics
– Isotactic, atactic, sydiotactic polypropylene definitions– Differences between PP and PE– Molecular Weight definition and forms (Weight Average,
Mw, and Number Average, MA )– Polydispersity definition and meaning– Relation between Molecular weight and Degree of
Polymerization (DP)– Mechanical, physical, and processing properties of PP,
Polybutylene, and polymethylpentene– PP is produced with linear chains
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Section Review
• Key Terms and Concepts– Polyolefin– Molecular weight– Number average molecular weight, weight average MW– Polydispersity– Polymer shrinkage– Polymer blends– Tensile Modulus– Izod Impact Strength
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Homework Questions1. Define Polyvinyls, PS, PP, HDPE, chemical structure.
2. Compare the density PVC, PVB, PS, and PVDC which is higher/lower than PP.
3. Compare the density of HDPE, LDPE, UHMWPE, LLDPE to PP?
4. What is the tensile strength of PP with 0%, 30% glass fibers? What is the tensile modulus?
5. Plot tensile strength and tensile modulus of PVC, PS, PP, LDPE and HPDE to look like:
Tensile Strength,Kpsi
Tensile Modulus, Kpsi200 500
10
50
xLDPE
xHDPE
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Homework Questions1. Define Polypropylene chemical structure2. Does commercial PP have Isotactic, atactic, sydiotactic form.3. If MW of PP is 200,000, what is the approx. DP?4. Polydispersity represents the distribution of _______and _____5. Density of PP is _____ which is higher/lower than HDPE.6. PP mechanical properties are higher/lower than LDPE and HDPE7. Plot tensile strength and tensile modulus of PP, LDPE and HPDE to
look like the following
Tensile Modulus,Kpsi
Tensile Strength, Kpsi2 5
10
50
xLDPE
xHDPE
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Homework Questions8. Four typical Physical Properties of PP are Optical = _______, Resistance
to moisture= ______ , UV resisance= _____, solvent resistance=_______ 9. The Advantages of PP are ________, ________, _______, and
__________.10. The Disadvantages of PP are ________, ________, _______, and
__________.11. Glass fiber affects PP by (strength) ________, (modulus)________,
(impact)_______, (density) __________, and (cost) ____________.12. Five polyolefins are ________, ________, _______, ______, and
__________.