School Science Lessons
Appendix D
Polymers and plastics
2019-07-27
Please send comments to: J.Elfick@uq.edu.au

Table of contents
3.0 Polymers and plastics
Table of contents
See: Plastics, (Commercial)
Polymers, 3.0.1
Polymers, Experiments
Polymers, plastics, and synthetic fibres: 2.0.0
Plastic bag over leaves, Transpiration: 9.194.1
Plastics manufacture: 9.0
Plastics recycling code, Resin Identification Code, ASTM: 3.5.3
Polymer foam: 3.5.1
Polymerization polymer: 3.6.9
Polymerization reaction: 16.2.4.2.1
Polymorphism polymer: 3.6.10
Polypeptides, peptides
Resins and gums: 3.0.0
Thermoplastic polymers: 3.0.2
Thermosetting polymers: 3.0.3

Experiments:
Breakdown polymers with heat: 3.97
Breakdown polymers to small molecules: 3.4.4.0
Ignite a celluloid ping-pong ball: 3.5.7.1 (Dangerous experiment!)
Polymers and plastics: 3.4.0
Sodium alginate polymer: 3.4.12
Tests for plastics, natural fibres and synthetic fibres: 3.102
Tests for polymers: 4.0.0
Tests for thermoplastic or thermoset plastic: 4.1.4

4.0.0 Tests for polymers
Need to specify: 1. repeat units, 2. molecular mass distribution (MMD), 3. chains, 4. fillers.
Identification methods include infra-red, and nuclear magnetic resonance spectroscopy, also swelling tests for thermosets.
Sometimes the polymer can be degraded to soluble products and these can be identified.

2.0.0 List of polymers, plastics, and synthetic fibres
("Poly" is the prefix denoting a polymer)
ABS Mixed polymer: ABS
Acetals, (alcohol + aldehyde), RCH(OR')2: 16.1.3.8
Acetate polymer: 3.5.8
Acetal: 16.1.3.8
Acrilan polymer: 3.7.5
Acryl polymer, Generic name for fibres > 85% acrylonitrile units
Acrylic acid, "acrylics": 3.4.2.8.1
Acrylic resin, Polymethyl methacrylate, PMMA, Perspex, (Lucite): 3.7.24
Acrylonitrile rubber
Addition polymers: 3.4.2
Alcantara polymer, Synthetic suede from polyester fibres in a polyurethane matrix
Alginate polymer: 3.4.12, (Experiment)
Alkyd resin: 16.9.1
Amber, C12H20O, succinite: 35.23.2.1
Amino-plastics, (UF), (MF): 3.8.5
Aniline-formaldehyde: 3.8.6
Araldite polymer, Epoxy resins: 3.8.7
Aramide polymer: 3.7.6
Aramid synthetic fibre: 3.7.6.1.1
Asphalt, bitumen
Azlon synthetic fibre
Bakelite polymer: 3.8.10
Balata polymer, Natural trans-1, 4-polyisoprene: Rubber, latex
Bamboo fibre
Ban-lon synthetic fibre
Bisphenol-A, (BPA), Epoxy resin polymer
British Celanese
Brominated Flame Retardants, (BFRs): 3.0.5
Carbon fibre, synthetic fibre, CarbonCast
Casein: 3.5.6
Casein, Prepare casein plastic from milk: 3.100
Cellophane, celluloid polymer: 3.5.7
Ignite a celluloid ping-pong ball: 3.5.7.1 (Dangerous experiment!)
Cellulose acetate: 3.5.8
Cellulose nitrate, nitrocellulose: 3.5.9
Cellulose triacetate: 3.5.8
Chemical sources of polymer materials: 3.4.02
Collodion, cellulose nitrate 3.5.10
Condensation polymers: 3.4.3.0
Conex synthetic fibre
Codura synthetic fibre
Composite materials, reinforced plastics: 9.1
Courtelle, polyacrylic fibre
Darlexx synthetic fibre
Density of polymers: 3.6.1
Derclon synthetic fibre
Diolen polymer: 27.189
Dralon polymer, Fibres from polyacrylonitrile
Dyneema synthetic fibre, Spectra synthetic fibre
Dynel synthetic fibre
Elasterell synthetic fibre
Elastomer polymers: 3.6.2
Electrostatic series, triboelectric series: 31.1.02
Epoxy resin polymers: 3.4.3.1
Ethylene vinyl acetate, (EVA) used in sports shoes
Fibreglass synthetic fibre, glass fibre
Formaldehyde-resorcinol resin, Prepare: 3.4.6.1
Glass transition temperature, (Tg): 3.4.01
Glycerol-phthalic anhydrides: 3.8.8
Grilen polymer: 27.189
Gutta percha polymer, natural polymer, mainly trans-1.4-polyisoprene, (latex of Palaquium oblongifolium)
Gold Flex
Hair, Fibrous proteins and globular proteins: 16.3.6.0.2
Horn: 3.4.1.1
Hostalen polymer, Polyethylene thermoplastic
Hostalen PP polymer, Polypropylene thermoplastic
Hostalit polymer, Polyvinyl chloride, thermoplastic
Hostaphan polymer, Films from polyethylene terephthalate: 27.189
Igelit polymer, Polyvinyl chloride, thermoplastic
Imides, imido group: (-CONHCO-), (R1CO-NH-COR2): 16.1.5.8
Ingeo synthetic fibre
Initiator polymer: 3.6.3
Innegra S synthetic fibre
Isomerization polymer: 3.6.4
Kevlar, Kevlar KM2, synthetic fibre, polyamide: 3.7.6.1.1
Lastol synthetic fibre
Lupolen polymer, Polyethylene thermoplastic
Luran polymer, Thermoplastic from styrene and acrylonitrile
Lyocell cellulose fibre
M5 synthetic fibre
Marlex polymer, Thermoplastic polyethylene
Melamine-formaldehyde resins, Formica, Bakelite, thermoset plastics: 16.2.4.2.1
Memory foam, (polyurethne): 3.7.34.1
Metallic fibre
Modacrylic synthetic fibre
Modal textile cellulose fibre
Moltopren polymer, Cellular polymer from polyurethane
Monomer polymer: 3.6.5
Mylar polymer, Polyethylene terephthalate, PET, thermoplastic: 27.189
Nomex synthetic fibre, polyamide: 3.7.6
Nylon polymer: 3.7.6.1
Neoprene polymer, polychloroprene: 3.7.12
Nitrocellulose
Nylon polyamide: 3.7.6.1
Olefin synthetic fibre.
Orlon polymer: 3.7.5
Perlon polymer: 3.7.6.1
Phthalates: 3.0.4
Phenols: 16.1.3.2
Phenolics: 3.8.10
PLA synthetic fibre: 16.1.3.2
PLGA synthetic fibre
Plasticizer polymer: 3.6.7
Plastics manufacture: 9.0
Plastics recycling code, ASTM: 3.5.3
Plexiglas polymer, Thermoplastic, polymethyl methacrylate
Polaroid sheet: 3.6.12
Poly-, polymers and plastics
Hostalen polymer, Polyethylene thermoplastic
Lupolen polymer, Polyethylene thermoplastic
Mylar polymer, Polyethylene terephthalate, PET, thermoplastic: 27.189
Polycaprolactam, Perlon plastic, Fibre from polycaprolactam: 3.7.6.1
Polychlorinated biphenyls, PCBs : 3.7.13
Polyethylene: 3.7.16
Polyethylene glycol: 3.5.4
Polyethylene glycol, zinc plating of copper: 15.1.6
Polyethylene oxide, PEO: 3.5.5
Polyethylene terephthalate, PET: 27.189
Poly(p-phenylene sulfide), Reactions of chlorine with benzene: 13.4.6
Polyacetals, Acetals: 3.7.1
Polyacetylenes: 3.7.2
Polyacrilimide: 3.7.4
Polyacrylamides: 3.7.3.0
Polyacrylic acid:
Polyacrylonitrile, PAN: 3.7.5
Polyamide, aromatic compounds: 16.3.4.0
Polyamides: 3.7.6
Polybenzimidazoles, PBI: 3.7.38
Polybrominated biphenyl, PBB: 16.14.1
Polybutadienes: 3.7.7
Polybutenes: 3.7.9
Polybutylene terephthalate, PBT: 3.7.8
Polycaprolactone, PCL: 3.7.11
Polycarbonates, PC: 3.7.10
Polychlorinated biphenyls, PCBs, "biphenyl": 3.7.13
Polychloroprene, neoprene: 3.7.12
Polydioxanone synthetic fibre
Polyelectrolytes: 3.4.2.1
Polyester synthetic fibre: 3.6.8
Polyesters: 3.7.14
Polyethenes, PE, polyethylene, polyisobutylene: 3.7.16
Polyether ether ketones, PEEK: 3.7.39
Polyethers: 3.7.15
Polyethylene: 3.7.16
Polyethylene glycol: 3.5.4
Polyethylene glycol, zinc plating of copper: 15.1.6
Polyethylene oxide, PEO: 3.5.5
Polyethylene terephthalate, PET: 27.189
Polyhydantoin: 3.7.21
Polyhydroquinone-diimidazopyridine, M5 synthetic fibre, PIPD
Polyimides, PI: 3.7.40
Polyisoprenes, isoprene, natural
Polylactic acid
Polymer density range: 3.6.1
Polymer foam: 3.5.1
Polymerization reactions: 12.2.7.0
Polymers: 3.0.1
Polymers and plastics, (Experiments): 3.4.0
Polymers, Hygroscopic polymers: 3.0
Polymers, plastics, and synthetic fibres, List: 2.0.0
Polymers, Thermoplastic polymers: 3.0.2
Polymers, Thermosetting polymers: 3.0.3
Polymethanal: 3.7.23
Polymethyl methacrylate, Perspex, (Lucite): 3.7.24
Polymethylpentene, PMP: 3.7.41
Polyolefins, polyalkanes: 3.7.25
Polyphenols:
Polyphenylenes: 3.7.26
Polypropenes: 3.7.27
Polypropenonitrile: 3.7.28
Polysilicates: 35.14.1
Polysiloxanes, silicones, PVMQ: 7.2.7
Polystyrene, PS: 3.7.29
Polysulfides: 3.7.30
Polysulfones: 3.7.31
Polyterpenes, rubber: Rubber, latex
Polytetrafluoroetheylene, PTFE, "Teflon": 3.7.32
Polytetrafluoroethylene: 5.0
Polytetramethylene ether glycol, PTMEG: 3.7.33
Polytrifluorochloroetheylene, PTFE: 3.7.32
Polyurethanes: 3.7.34
Polyvinyl acetals: 3.7.35
Polyvinyl acetate: 3.7.36
Polyvinyl acetate, Prepare slime, PVA slime: 3.4.11
Polyvinyl alcohol, PVA, PVOH: 3.6.13.1
Polyvinyl chloride, PVC: Polyvinylchloride
Polyvinyl pyrrolidene, povidone: 16.3.5.2.8
Polyvinyl pyrrolidone, food additive, E1202, synthetic protein, stabilizer, wine clarifier
Polyvinyls: 3.6.13
PrimaLoft synthetic fibre
Qiana, silky nylon fibre
Rayon polymer: 3.8.14
Reinforced plastics: 9.1
Retroglo synthetic fibre
Rubber:
SAN Mixed polymer: SAN
Saran wrap, Vinyls, vinyl polymers: 3.6.13
Shellac:
Silicones: Volasil
Silly string, (toy product): 3.5.2
Silly putty, (toy product): 3.4.11
Spandex polymer, Generic name for elastic fibres from polymers >85% segmented polyurethane
Styrenes: 3.7.29
Styrofoam: 3.7.29
Super ball, (toy product): 3.4.04
Synthetic fibres, synthetic resins: 3.6.14
Tactel synthetic fibre
Taklon synthetic fibre
Technora synthetic fibre, polyamide: 3.7.6
Teijinconex synthetic fibre, polyamide: 3.7.6
Terital polymer: 27.189
Terlenka polymer: 27.189
Terylene polymer: 3.7.20
Thermoplastic polymers: 3.0.2
Thermosetting polymers: 3.0.3
Thinsulate synthetic fibre
Trevira polymer: 27.189
Triacetate polymer, fibres from cellulose triacetate
Tricel polymer, fibres from cellulose triacetate
Trogamid, polyamide: 3.7.6
Twaron synthetic fibre: 3.7.6
Ultem (Trade name), Polyether imides are melt-processible imides linked by ether (-O-) groups in the main chain.
Urea-formaldehyde plastics: 3.8.11
Urea-formaldehyde resin, Prepare: 3.101
Vectran synthetic fibre
Vestolit polymer, Polyvinyl chloride
Vinalon synthetic fibre
Vinyl chloride, C2H3Cl: 3.6.13.01
Vinyls, vinyl polymers: 3.6.13
Vinyon synthetic fibre
Viscose polymer, fibres from regenerated cellulose, cellulose xanthate forms
Viscose rayon textile fibres
Vulcanization: 3.6.11
Ziploc bags:
Zylon synthetic fibre, PBO:
Zytel polymer: 3.7.6

Polyvinyl chloride, PVC
Polyvinyl chloride, PVC, polychloroethene: 3.7.37
Models, organic, Polyvinyl chloride (PVC), model, "Scientrific" (commercial website)
Polyvinyl chloride plastic, (PVC) may contain and leach to the environment dangerous chemicals, e.g. the phthalate bisphenol A.
Calendering, Polyvinyl chloride, 9.5.1
Hostalit polymer, Polyvinyl chloride, thermoplastic
Phthalates: 3.0.4
PVC, Plastics recycling code, recycling symbols: 3.5.3
PVC, Polymer Density: 3.6.1
Vestolit polymer, Polyvinyl chloride3.7.6
Vinyls, vinyl polymers: 3.6.13

9.0 Plastics manufacture
Machine processes
9.1.0 Extrusion, Profiles, tubes, pipes, sheets, films, cable sheathing
9.2.0 Injection moulding, Mouldings, e.g. cups, gear wheels, telephones, milk bottle crates
9.3.0 Blow moulding, Bottles and containers
9.4.0 Rotational moulding, Tanks, drums, household goods
9.5.0 Calendering, Plastic sheet
9.6.0 Foaming
9.7.0 Laminating, Plastic laminated with paper, wood, metal
9.8.0 Compression moulding, Mouldings, sheets, blocks
9.9.0 Thermoforming, Deep drawing of beakers, packaging, baths, boat hulls

Manual processes
10.0 Casting, Blocks, sheets, mouldings, coating
Mouldings, encapsulation
11.0 Foam pouring, Space filling, coating, large mouldings
12.0 Reinforcing, Mouldings, lining, coating
13.0 Manual Thermoforming, Welding and bending of pipes and craft shaping

9.1 Composite materials
Composite materials, reinforced plastics, are made by combining a thermosetting resin, e.g. polyester or epoxy resins, with a
reinforced base, e.g. fibre glass, carbon fibre.
The combination increases mechanical resistance to manufactured goods, e.g. car bodies, boats, aircraft and bicycle frames.

3.0.0 Resins and gums
3.4.01 Chewing gum, Glass transition temperature, (Tg), (See 2.)
9.0.0 Glues and pastes, adhesives, gums, (Preparations)
19.4.4.26 Stabilizers, thickeners, food additives, gums
19.4.4.27 Vegetable gums, food additives, gums
Resins are flammable aromatic substances found mainly in the resin ducts of conifers, which contain organic polymers and terpenoids.
They may be extruded naturally or by incision, then become sticky or hard.
Unlike gums, they are insoluble in water.
Any synthetic materials resembling resins may be called "resins" or "synthetic resins", e.g. phenol resins, (Bakelite), epoxy resins.
They may be solid or liquid and thermosetting or thermoplastic.
Synthetic resins are used to make plastics.
Resinoids are synthetic resins that are thermosetting or not permanently solid or fusible.
However, "resinous" usually refers to natural resins.
Natural gums are similar to resins that harden on drying but which dissolve or swell in water.
Both natural and synthetic gums may be used for glues, stiffening and in foods.
Gum trees usually refers to Eucalyptus.

3.0.1 Polymers
1. Polymers are large molecules built up by repetition of small and simple chemical units called monomers.
For example, (+) glucose is the unit of starch, and ethylene, (ethene), is the unit of polythene.
Polymers are long chain molecules formed by polymerization, the combination by step-by-step repetition of groups of atoms called
repeat units, e.g. -CO-O- in polyesters.
The chain length of polythene is about five thousand ethene units.
The mechanical properties of polymers depend on their molecular size.
Polymers melt at a characteristic temperature that may be changed by impurities and additives.
Some polymers, e.g. forms of polystyrene and forms of polypropylene can crystallize at a certain temperature to change their thermal
and mechanical properties, increase their density and contract more after moulding.
Regular polymers normally crystallize and may be cooled from the melt so quickly to allow crystallization, e.g. polyethylene
terephthalate film is amorphous owing to cooling at a high rate.
The two main categories of polymers, thermoplastics and thermosetting resins, are based on their molecular structures and their
behaviour on heating during manufacture.
2. Synthetic polymers are formed by chemical reactions for making plastics where monomers are joined by polymerization and
condensation.
3. Homopolymers form from the same monomer, e.g. ethene, CH2CH2, is polymerized to form polyethene, (polyethylene).
-CH2-CH2-CH2- .
4. Heteropolymers, (copolymers), are made from different monomers, e.g. ABS plastics are made from acrylonitrile, butadiene, and
styrene copolymers. ABS is the generic name for plastics made from Acrylonitrile, Butadiene and Styrene units.
5. Synthetic resins are polymer compounds before curing.
6. Natural products, cellulose in wood and cotton, horn, rosins, raw
7. Converted natural products, vulcanized, vulcanized fibre, celluloid, (cellulose nitrate), casein plastic, (artificial horn)

3.0.2 Thermoplastic polymers
"Thermoplastic Polymer, polycaprolactone", (commercial)
When thermoplastic is dyed no chemical reaction occurs and moulding is not irreversible because thermoplastics can be returned to
their plastic state and back to a solid state without losing their characteristic.
Thermoplastic polymers, thermosoftening plastic, have long chain molecules that soften on heating and harden on cooling to a glassy
state without significant chemical change.
They can be melted and moulded again and again.
This plastic is heated to soften it, then squeezed to fuse it and to shape it by viscous flow.
Most polymers are thermoplastics.
Usually have high molecular weight with weak Van der Waals bonds between molecule chains that can be broken by heating, e.g.
polyethylene, nylon, polystyrene, polypropylene.

3.0.3 Thermosetting polymers
Thermosetting polymers are polycondensed material so that during manufacture when it is heated and subjected to pressure, a
chemical reaction occurs provoking a restructuring that is molecularly irreversible.
Once formed, a thermosetting resin is unchangeable.
Thermosetting polymers are extensively cross-linked to form 3-D networks that does not soften much on heating.
A network of strong covalent bonds forms during the initial curing so the material cannot be remoulded.
Thermosetting plastics have rigid cross-linked molecules, resist high temperatures, cannot be softened after curing.
Insoluble, hard and brittle substances.
They are polymers that once formed does not melt on heating, charring instead.
Its structure has cross-linking from one chain to the next produced by chemical curing.
These thermosets cannot be recycled, e.g. phenol resins, (Bakelite), epoxy resins, melamine-formaldehyde resin, polyimides, polyesters,
silicones, fibreglass, urea-formaldehyde foam, vulcanized, some polyurethanes.
Thermosetting resins include phenolic, melamine, urea and polyester resins.
Cross-linking of polymers chains occurs while resins are being moulded resulting in high temperature stability due to vast network of
covalent bonds between the chains.
They cannot be melted or recycled because they are resistant to further heating up to charring point.

3.0.5 Brominated Flame Retardants, (BFRs)
The BFRs, used to reduce flammability of clothing and furnishings may cause
human health problems.
For example, Hexabromocyclododecane, (HBCD), and Tetrabromobiphenol A, (TEEPA)
are toxic to water organisms and may be present in polystyrenes and polyesters.

3.4.2 Addition polymers
See diagram 16.3.4.2: Vinyl polymers
Addition polymerization occurs when identical monomers link under high temperature and pressure.
The reactive group is the carbon to carbon double bond [C=C].
For example, many units of ethylene, (ethene [CH2=CH2]), combine to form polyethene, (polythene), [-CH2-CH2-CH2-CH2-].
That is the only product of the reaction and it has no definite chemical formula.
For example, phenylethene polymerizes to form poly(phenylethene), polystyrene, styrene.
Addition polymers are called thermoplastic, (thermosoftening), polymers because they melt easily.
They may be recycled because they can be melted and used again but, when they burn, they may form poisonous gases.
Addition polymerization, chain polymerization involves activating monomer molecules with a catalyst, benzoyl peroxide that splits to
give two free radicals that reacts with a monomer to form another free radical, (initiation), that reacts with more monomers to
form a polymer chain.
The two free radicals react together to stop the reaction or react with another chain to form branching chains.
Chain growth polymers include polyethylene, vinyl polymers, polybutadiene

3.4.2.1 Polyelectrolytes
They can absorb up to 1 000 times their weight in water, gel capacity, and
are known as "Super Absorbents" and "Water Crystals".
When dry, the polymer is a white powder and when in gel form it is a transparent gel.
It is used in diapers, bed pads, fire control, spray drift control, seed germination, soil conditioning, menstruation period pads, and
hydroponics.
It is sensitive to the salts in hard water, so dissolved minerals decrease absorption capacity.

3.4.2.8.1 Acrylic acid, "acrylics"
Acrylic acid, propenoic acid, CH2CHCOOH, synthetic fibre, acrylic resins, "acrylics"
"Expanding Snow", sodium polyacrylate, (commercial)
"Super Slurper Polymer", with sodium polyacrylate water disappears, (commercial)

Poly(propenenitrile), acrylic, "Acrilan", "Courtele", (monomer H2C=CHR, where R = -(C triple bond N).
Acrilan, (trade name), polyacrylonitrile, PAN, thermoplastic polymer, synthetic fibre:
Acrylic acid is manufactured from propylene, (from catalytic cracking of petroleum), in two steps via acrolein in a gas phase using
special catalysts.
CH2=CHCH3 (propylene) + O2 --> CH2=CHCHO (acrolein) + H2O
CH2=CHCHO + 1/2O2 --> CH2=CHCO2H (acrylic acid)
acrylic acid + NaOH (+ initiator) --> (cross-linked) polyacrylic acid sodium salt, sodium polyacrylate, (in baby disposable diapers,
water-saving crystals, water jelly crystals, wetting agents, "hydrogel")
Acrylics may refer to any of the following chemicals derived from acrylic acid, e.g. acrylic fibre (acylonitrile), acrylic paint in an acrylic
emulsion), acrylic resin, e.g. polymethyl acrylate, acrylic glass (polymethyl methacrylate, PMMA), acrylate polymers.
Acrylic glass transmits UV light down to 300 nm.
However, an additive can make it absorb light when used for aquariums and architecture.
Commercial
Acrylic cement, clear fluid, 29 mL
Acrylic offcuts, white, clear, colours
Acrylic sheets 800 mm width × 600 mm depth × 3 mm height, clear
Acrylic sheets 800 mm width × 600 mm depth × 3 mm height, translucent red, grey, amber
Acrylic sheets 800 mm width × 600 mm depth × 3 mm height, opaque, red, yellow, white, green
Acrylic sheets 800 mm width × 600 mm depth × 3 mm height, fluorescent, pink, green, orange, blue, black

3.4.3.0 Condensation polymers
Condensation polymers need two, usually different, reactive monomers with two functional groups to link with the loss of a small
molecule, e.g. water or hydrogen chloride, to form a polymer.
The reaction is similar to the formation of esters and starches.
These reactions may be thermoplastic, (softening on heating), or thermosetting, (do not soften on heating).
You cannot recycle thermosetting plastics.

3.4.3.1 Epoxy resin polymers
Epoxy resin polymers are formed by polymerizing epoxide compounds [R1COCR2] with phenols [C6H5O-] epichlorhydrin and
bisphenol-A, BPA.
Epoxy compounds, (O atoms in CCO ring), Epoxy resin polymersbr> Some are thermoset plastics.
They are used as surface coatings, liquids, resins, hardeners, fibre-reinforced sports equipment, aeroplanes, boat parts, casting resins,
and embedding electronic components because of resistance to chemicals.
They are also used as adhesives that have a two pack system of a resin and a hardener, silicon tetrachloride.
Acetone is a curing agent for epoxy resin adhesives.
Epoxy, contains group -C-O-C, as in epoxides, a cyclic ether, thermosetting synthetic resins, in coatings to resist chemical attack and
adhesives, hardened by polyamines to form cross-linkages.
Have an oxygen atom attached to two carbon atoms of a carbon chain or ring system, so are cyclic ethers, e.g. 1, 2-epoxypropane.
Epoxy resins are fibre glass resins.
Bisphenol-A

3.4.3.2 Polyacetals
Polyacetals, polyoxymethylene resin, acetyl resin, polyformaldehyde, POM, "Kematal", "Delrin" resist abrasion and resist organic
solvents and water.
This moulding polymer is widely used in engineering products, e.g. gear wheels, plumbing to replace brass or zinc and in pens.
It may be copolymerized with ethylene oxide to increase stability and not become depolymerized.

3.4.04 Super ball, (toy product)
Super ball is made from polybutadiene with small amounts of sulfur to reinforce the material and serve as a vulcanizing agent.
The ball is moulded under very high pressure and temperature and is said to have a 92% resiliency, about three times the resiliency of
a tennis ball.
It can continue to bounce for about a minute after being dropped from a short height.

3.4.1.1 Horn
Horn contains 80% keratin, is thermoplastic and can be worked after dry heating or immersion in boiling water or alkaline solutions,
then pressed to form objects, e.g. boxes, buttons, pens and combs, and laminas.
Dry horn dust can damage the lungs.

3.5.1 Polymer foam
See diagram 16.3.4.10: Polyurethane
The latex of natural has a low glass transition temperature so foam is always flexible.
Polystyrene has a high glass transition temperature so its foams are rigid.
Polyurethane foams can be flexible or rigid depending on the formulation so they can be used for soles of shoes.
The foaming agent may be air or a "blowing agent" that decomposes to a gas on heating.

3.5.2 "Silly string", (toy product)
Mixture of polyisobutyl methacrylate, sorbitan trioleate and a solvent that evaporates in the air contained in an aerosol can.
Release of pressure causes a thin spurt to shoot out and harden in the air as a string.
The product is a nuisance, but it is supposed to be useful for detecting hidden wires in dark places, e.g. trip wires.

3.5.3 Plastics recycling code
Plastics recycling code, ASTM, Resin Identification Code
See diagram 16.3.5.1: Recycling code
ASTM International, formerly known as the American Society for Testing and Materials (ASTM), is proposing to replace the chasing
arrows in the current code with solid equatorial triangles to help clarify that the code is designed for resin identification purposes and
not recyclability.
The codes from the Society of the Plastics Industry are found on the bottom of plastic packaging.
1. PETE, Polyethylene terephthalate, commonly recycled, relatively safe plastic designed for single use
2. HDPE, High density polyethylene, commonly recycled, relatively safe plastic for use in food and drink containers
3. PVC, Polyvinyl Chloride, Vinyl chloride, V, not commercially recycled, may contain and leach dangerous chemicals
4. LDPE, Low density polyethylene, less commonly recycled, relatively safe plastic for use in food and drink containers
5. PP, Polypropylene, not commercially recycled, relatively safe plastic for use in food and drink containers
6. PS, Polystyrene, not commercially recycled, may contain and leach dangerous chemicals
7. PC or Other, Polycarbonates, layered or mixed plastic, with no recycling potential so must be disposed of by land fill, may contain
and leach dangerous chemicals

Uncoded plastics are not usually recycled, but disposed of in land fills.
8. Avoid putting the following into recycling bins:
8.1 Soft plastics, e.g. cling wrap, bubble wrap, biscuit trays, potato chip packets, drinking straws, plastic coffee cups.
Avoid any plastics which can be scrunched into a ball in the fist.
8.2 Plastic coat hangers damage recycling machinery.
8.3 Paper towels reduce the quality of recycled paper and are a health issues for recycling workers.
8.4 Photographs contain damaging chemicals.
8.5 Plastic bags damage recycling machinery, so do not store recyclable items, e.g. plastic bottles, in plastic bags.

3.5.4 Polyethylene glycol
Polyethylene glycol, poly(ethylene glycol), PEG, H(OCH2CH2)nOH
Polyethylene glycol, PEG, HO-CH2-(CH2-O-CH2)n-CH2OH, polymer of ethylene oxide, different molecular masses
measured in g / mol, melting point depends on formula weight, low toxicity but toxic impurities can damage broken skin, (Trade name,
"Carbowax"), used as initiator of polymerization process, printer ink, "Paintball" bullets, wood in salvaged ships, high osmotic pressure
solutions, monoclonal antibody production, non-ionic surfactants for cosmetics and pharmaceutics, e.g. laxatives, toothpaste, eye drops.

3.5.5 Polyethylene oxide
Polyethylene oxide, poly(ethylene oxide), PEO, (-CH2CH2O)n
Polyethylene oxide, PEO, "Poly-Ox"
It is a self-siphoning gel with repeating unit, -CH2-CH2-O-)
It is water-soluble and is used in cosmetics, toothpaste, water used for fire fighting.

3.5.6 Casein
Casein, milk casein, casein plastic, (artificial horn), thermoset plastic
Milk casein, phosphoprotein thermoplastic polymer, for insulators, buttons, handles, adhesives, artist's priming paint
Casein formaldehyde was made from milk, soy beans, wheat, may look like celluloid or artificial horn, was used to make buttons,
umbrella handles and radio cabinets.

3.5.7 Celluloid
Cellophane polymer, Films from regenerated cellulose
Celluloid, cellulose nitrate, cellulose acetate, thermoset plastics
Celluloid, thermoplastic, is synthesized from cellulose nitrate, cellulose-based fibres, (rayon, cellophane), viscose cellulose film,
celluloid.
A flammable thermoplastic that decomposes, made from nitrocellulose + camphor, (not used nowadays except for ping-pong balls,
guitar picks, spectacle frames, hair adornments).
It was the first of the artificial plastic materials, invented by J. W. Hyatt using cellulose nitrate and camphor.
Celluloid objects are easy to manufacture, starting from plates, sheets, sticks, tubes strips and film.
Celluloid can be sawn, cut, laminated, folded, punched, stretched, twisted, pressure moulded, sewn, nailed and seamed and can be
modelled simply by heating it with hot water or air, it can be glued and superficially decorated.
However, celluloid cannot be injected or compressed or extruded as it is decomposed at the temperature necessary for such processes.

2. Polynosic fibres are rayon fibres with improved qualities of uniformity.
The first thermoplastic was discovered 1862, but the name "celluloid" in 1870.
Also, cellulose propionate, cellulose butyrate, ethyl cellulose.

3.5.7.1 Ignite a celluloid ping-pong ball
Ping-pong balls are made from cellulose nitrate.
Igniting ping-pong balls is potentially a dangerous demonstration and should only be done by a responsible adult wearing safety gear.
Use tongs to hold the ball.

3.5.8 Cellulose acetate
Cellulose acetate, CA, acetate, cellulose fibre, artificial fibre
Acetate polymer is a generic name for fibres from cellulose acetate, CA Cellulose acetate, "acetate", zylonite, (cellulose ethanoate),
cellulose acetate butryate CAB, thermoplastic, used in calculators,
cigarette filters, fibres, knife handles, shoe heels, switches, typewriter keys, umbrella handles, toys.
One of the first injection-moulded plastics.
White powder.
Cellulose acetate, (cellulose ethanoate), easy to ignite, yellow flame, burns after removing flame, acidic fumes, acetic acid smell
Cellulose acetate, CA, acetate plastic, cellulose fibre, artificial fibre
Cellulose-based fibres, (rayon, cellophane), viscose cellulose film, celluloid
Cellulose triacetate, TAC, triacetate, [C6H7O2(OOCCH3)3]n, used in clothing fibres, packaging, photographic film, semipermeable
membrane

3.5.9 Cellulose nitrate
Cellulose nitrate, nitrocellulose, flash paper, guncotton, made from cellulose, (starch, wood, cotton), + nitric acid, highly
flammable, explosive
3HNO3 + C6H10O5 --> C6H7(NO2)3O5 + 3H2O

3.5.10 Collodion, cellulose nitrate
Starting in 1846 collodion was made by soaking cotton or cellulose in nitric acid and sulfuric acid, dried the dissolves in pyroxylin, (ether
and alcohol)
It was a colourless to yellow syrupy liquid that dried as an adhesive, so is still used to close small wounds and give a tough clear coating
to the prints of early photographic processes.
Collodion can be defined as cellulose nitrate dissolved in a mixture of ethanol or diethyl ether, cellulose tetranitrate.
In one early photographic process, cellulose nitrate + soluble iodide coats a glass plate then in darkroom immersed in silver nitrate to
form silver iodide.
Then the wet plate was exposed in a camera, then developed with pyrogallic acid and fixed with sodium thiosulfate or potassium
cyanide solution.

3.6.1 Polymer density range
Density range = g / cm-3
EPS, expanded polystyrene 0.02-0.06
PP, polypropylene 0.89-01.91
LDPE, low density polyethylene 0.91-0.93
HDPE, high density polyethylene 0.94-0.96
PS, polystyrene 1.04-1.1 1
PVC, polyvinyl chloride 1.20-1.55
PET, polyethylene terephthalate 1.38-1.40

3.6.2 Elastomer polymers
A polymer material with elastic properties, namely the ability to snap back to the original dimensions after distortion.
Cross-linked molecules but with fewer linkages than thermosets, can swell in solvents to become y, regain shape after distortion.

3.6.3 Initiator polymer
A substance used to start a chain polymerization reaction, e.g. a free radical.
Polyethylene glycol is used as initiator of polymerization processes.

3.6.4 Isomerization polymer
Isomers are molecules with the same molecular composition and relative molecular mass but different arrangement of atoms, e.g. butane
and isobutane are both C4H10.
Isomerization is the rearrangement of the geometry of a molecule without changing its overall formula.

3.6.5 Monomer polymer
A simple molecule that is joined to others to form a dimer, trimer, or polymer.

3.6.7 Plasticizer polymer
A plasticizer polymer is an additive that makes a polymer material more flexible or less rigid.

3.6.8 Polyester synthetic fibre, embedding resin polymer
A viscous liquid of a polymerized unsaturated polyester dissolved in styrene monomer.
The methyl ethyl ketone peroxide catalyst cross-links the styrene to the double bonds in the polyester.

3.6.9 Polymerization polymer
The process by which single units, monomers, are joined to form a giant molecule, polymer.
A linear polymer has links only in one dimension forming a chain.
A cross-linked polymer has cross-links between chains.
1. Addition polymerization is the coupling of monomers, e.g. form polyethylene from polythene.
Addition polymers include polyethylene, polypropylene, polyvinyl chloride.

2. Condensation polymerization is the coupling of two monomers covalently by the loss of water, so one loses an (-OH) group and
the other loses an (-H) group
Condensation polymers include polyurethane, polyethylene terephthalate, Nylon 6.6.
Natural condensation polymers include disaccharides, polysaccharides, proteins from amino acids, nucleic acids, e.g., DNA, RNA.

3.6.10 Polymorphism polymer
Substance occurs in distinct solid forms.

3.6.11 Vulcanization
Rubber
Polyterpenes, (many isoprene units), e.g. rubber, (C5H8)n
Vulcanization is a thermosetting process to treat and -like polymers with sulfur and heat to improve elasticity, and strength or to harden
substances by forming cross-links between polymer chains.
Sulfur is added to the liquid latex of natural, (polyisoprene), to create cross-linkages.
Latex collected, ("tapped"), from the para rubber trees (Hevea brasiliensis) or other "trees", by cutting into the bark is coagulated
with acid, is collected in a latex bulking and blending tank, coagulated with formic acid or acetic acid, rolled into ribbed smoked sheets
and left to dry in a smoke house.
This soft is called crepe and was formerly used for the soles of sandals.
Very hard is ebonite, e.g. indoor bowling balls.

3.6.12. "Polaroid" sheet
Polaroid" sheet is birefringent material that absorbs most light in one of the directions while transmitting much of the other light.
Polaroid is made from plastic by adding a long chain molecule dye before stretching so that the dye gets orientated as well as the plastic.
Formerly, "Polaroid" was made from iodoquinine sulfate in nitrocellulose polymer film, but nowadays it is made from iodine in polyvinyl
alcohol (PVA) or polyvinylene.
Polaroid is dichroic, i.e. it absorbs light depending on the incident direction.
The chains of PVA polymer chains are stretched to form linear molecules aligned so that the attached iodine conducts light along the
length of the chains.
Light polarized parallel to the chains is absorbed.
Light polarized purpendicular to the chains is transmitted.
Polaroid sunglasses reduce any polarized light from reflected surfaces and so reduce glare.

3.6.13 Vinyls, vinyl polymers
Thermoplastic, polyvinyl, CH2=CH2, odourless, tasteless
See diagram 16.3.4.2: Vinyl polymers, vinylidene chloride, Polyvinylidene
The symbol | V | is the plastic identification recycling code 3 for vinyl chloride / polyvinyl chloride, (PVC), used for food wrap,
vegetable oil bottles, but not commonly recycled except in tests.
1. Polyvinyl acetate, (PVA), vinyl ethanoate, CH2COOCH=CH2, vinyl acetate monomer, used for adhesives and latex paints
2. Polyvinyl alcohol, water-soluble
3. Polyvinyl butyral, PVB, (interlayer in laminated safety glass screens in windshields of cars, windscreen cracks, e.g. "Butacite"
4. Polyvinyl carbazole, (xerography)
5. Polyvinyl formal, (lacquers, coatings)
6. Polyvinyl pyrrolidone, water-soluble, (cosmetics, with methyl methacrylate in soft contact lenses)
7. Polyvinylidene chloride, PVDC, (vinylidine chloride monomer, 1, 1-dichloroethylene, repeat unit, -CH2-CCl2-, cling wrap, (not
Australia), (Saran wrap, freezer bags), (coating for PET beer bottles, chemical-resistant piping), (co-polymer with PVC in Saran
polymer, >80% vinylidene chloride units)
8. Polyvinylidene fluoride, (repeat unit: -CH2-CF2-), (transducers in liquids, hydrophones)
9. Polyxylylene, (dielectric film)
Saran wrap, Vinyls, vinyl polymers

3.6.13.01 Vinyl chloride, C2H3Cl
Vinyl chloride monomer, C2H3Cl, H2C:CHCl, VCM, chloroethylene, chloroethene, chlorethene, is used to make polyvinyl chloride
(PVC) for plastic hoses, cable coatings, furniture, automobile upholstery, flooring, credit cards, containers, wrapping film.
It is an extremely flammable and unstable colourless gas with a mild, sweet odour.
Only people working with it can be harmed by it.
Breathing it causes headaches and unconsciousness leading to death.
On the skin it causes blisters like frostbite.
It is a possible carcinogen.

3.6.13.1 Polyvinyl alcohol, PVA
Polyvinyl alcohol, PVA, PVOH, synthetic polymer, (C2H4O)x, used in adhesives, textile size, synthetic fibres

3.6.14 Synthetic fibres
Synthetic fibres are manufactured by synthesis of a linear polymer then extruded molten through fine holes, spinneret, mainly
polyester, nylon, acrylic and polyolefin.
Synthetic resins are made by condensation reactions, e.g. phenol and formaldehyde, urea and formaldehyde, glycerol and phthalic
anhydride.
Synthetic resins are polymer compounds before curing.

3.7.1 Polyacetals
Polyacetals, thermoplastics, synthesized from aldehyde, (polyoxymethylene resin, POM), acetal resin, polyformaldehyde
Acetals, acetal [RCH(OR')2, CH3CH(OC2H5], smelly liquid, (gears, bearings, telephones, radios, television components)
See 16.1.3.8, Acetals, synthesized by alcohol with aldehyde

3.7.2 Polyacetylenes, -CH=CH-, are not yet developed as a plastic

3.7.3.0 Polyacrylamides
Polyacrylamides, synthesized from 2-propenide, transparent, cross-linked (used in polyacrylamide gel electrophoresis to
separate nucleic acids and proteins)
A polyacrylate is a polymer of acrylic acid ester.
"Instant Wet Snow", wet, shiny & sparkling snow powder + water, polyacrylamide, (commercial)
Electrophoresis, (Commercial)

16.1.5.6.1 Acrylamide, 2-propenamide, ethylene carboxamide, acrylic amide, vinyl amide
In water-soluble polymers for municipal water treatment to remove suspended solids, increase water viscosity to enhance oil recovery,
flocculants, paper-making aids, thickeners, soil conditioning agents, sewage and waste treatment, ore processing, and permanent-press
fabrics, slow dehydration of cement in 12% precast polyacrylamide gel, contact lenses, water-based paints.

3.7.4 Polyacrylimide
Polyacrylimide, synthesized from methacrylic acid and methacrylonitrile copolymer + urea, (rigid foam articles, e.g. propellor blades)

3.7.5 Polyacrylonitrile
Polyacrylonitrile, PAN, thermoplastic
Acrilan polymer, synthetic fibre, polyacrylic, Trade name for fibres from polyacrylonitrile
See diagram 16.3.4.2: Acrylonitrile, polyacrylonitrile, (at bottom of diagram)
Acrylic fibres, synthesized from at least 85% acrylonitrile, polyacrylonitrile from monomers vinyl acetate or methyl acetate, (textile
fibres, acrylic resin, Trade name "Orlon", "Acrilan").
Orlon polymer, orlon synthetic fibre, polyacrylic, Fibre from polyacrylonitrile: Polypropenonitrile is synthesized from the monomer
propenonitrile (acrylonitrile monomer, vinyl cyanide) [CH2=CHCN].
acrylics (acrylic acid, CH2, CHOOH), (acrylonitrile, CH2, CHCN) acronitriles, e.g. propenenitrile (fibres)

3.7.6 Polyamides
Polyamides: Dacron, Terylene, Nylon, Perlon, Natural polyamides
Aramide polymer, Generic name for fibres from aromatic polyamides
H2N-R + R'C=O(OH) --> R'C=ONHR + H2O
amine + carboxylic acid --> amide + water
NH2-XNH2 + C=O(OH)YC=O(OH) --> -NH-X-NH-C=O-Y-C=O-NH- + xH2O
diamine + dicarboxylic acid + --> polyamide + water
The amide linkage, -CONH-, is repeated to form polyamides from two different monomers:
1. a diaminoalkane, which has two amine groups) and
2. a dicarboxylic acid, which has two carboxylic acid groups.
Polyamides are natural and synthetic fibres, polymers with the amide group, -CO-NH-, repeated along the chain.
Natural polyamides include hair, silk and wool.
Polyamide PA 6, (natural), is a very useful plastic because it has good abrasion resistance for sliding elements, impact strength and
high ductility.
Its properties can be modified by additional stabilizers to change its properties.
Thermoplastic, condensation polymerization, synthesized from amino group with carboxylic acid group to form H bonding between
molecules with water or HCl eliminated.
Zytel polymer, Toughened nylon, various aliphatic polyamides

Polyamides are used in typewriter keys, gear wheels, screws, fibres, synthetic fabric "Dacron" "Terylene", radio and television
industries, precision gearing, protective film for foods, surgical instruments, prostheses, clothing. thermoplastic.
NH2-benzene-NH2 + HOC=O-benzene-C=OOH --> -NHbenzene-NH-C=O-benzene-C=O-NH + H2O
benzene-1, 4-diamine + benzene-1, 4-dicarboxylic acid --> Kevlar unit + water
Zytel Plus nylon resin offers higher performance levels and maintains them much longer than traditional nylons despite exposure to hot
oil, hot air, calcium chloride, (road salt), automotive coolant and other aggressive automotive chemicals.
Kevlar, Kevlar KM2, synthetic fibre, polyamide

3.7.6.1 Nylon polyamide
Nylon polymer, synthetic fibre, polyamide, Nylon 6, Nylon 6-6
Models, organic, Nylon 6.6, 76 atoms + links, build polymer chain, "Scientrific", (commercial website)
See diagram 16.3.4.7
: 6, 6 nylon and 6-nylon
See: 3.4.7 Prepare nylon polymer, (1, 6-diaminohexane)
Nylon polymer is a generic name for polyamides thermoplastics, synthesized from amino group with carboxylic acid group to form H
bonding between molecules, -CO-NH-.
The polyamid fibre nylon, (Germany: Perlon).
Perlon polymer, Fibre from polycaprolactam Nylon is generic name for polymers with amide groups in main chain.
The nylons are aliphatic homopolymer polyamides.

(1.) Nylon 6, polycaprolactam, (Perlon), synthesized by ring-opening polymerization of caprolactam, not condensation, (caprolactam
has 6 carbons)

(2.) Nylon-6, 6, synthesized from hexamethylenediamine (1.6-diaminohexane) and adipic acid, (hexane-1, 6-dicarboxylic acid,
hexanedioic acid), i.e. a 6 carbon diamine and 6 carbon adipic acid.
NH2(CH2)6NH2 + 2[COOH(CH2)4COOH] --> NH2(CH2)6NHCOOH(CH2)4COOH + H2O
1.6-diaminohexane + hexane-1, 6-dicarboxylic acid --> nylon-6, 6 unit + water

(3.) Nylon 6, 10, synthesized from 1, 6-diaminohexane, (6 carbon atoms, NH2-(CH2)6-NH2) and sebacoyl chloride, (10 carbon atoms,
C10H16Cl2O2)
Commercial: Nylon utensils, for use on non-stick surfaces, egg turner, 320 mm

3.7.6.1.1 Dacron
Dacron, thermoplastic, polyethylene terephthalate, PET
Aramid synthetic fibre, Nomex, Kevlar, Twaron, in food containers, fibres
Thermoforming aramid fibres are polyamides synthesized from aromatic groups attached to amide links
Natural polyamides, -CO-NH-, include hair, silk, wool.
See 16.3.4.0b: Aramids

3.7.7 Polybutadiene
Polybutadiene, elastomer, synthetic, polymer of 1, 3-butadiene

3.7.8 Polybutylene terephthalate
Polybutylene terephthalate, PBT, synthesized from 1, 2-butanediol and terephthalic acid, (thermoplastics)

3.7.9 Polybutenes
Polybutenes, synthesized from 2-methyl propylene, very high molecular weight, resists moisture, (hot and cold water pipes)

3.7.10 Polycarbonates
Polycarbonates, PC, thermoplastic, synthesized from bisphenol A, functional group -O.CO.O-, e.g. bisphenol A, (BPA), is used for
bullet proof glass and CR-39 is used for optical lenses
See 3.5.3, Plastics recycling code, Polycarbonate or Other, 7 PC or Other
Discovered separately in America and Germany in 1957.
Polycarbonates maintain their characteristics unaltered from 140oC to -100oC, have a very hard surface, good insulators and resist
atmospheric agents.
Polycarbonates retain their dimensions and resistance to impact and wide range of temperatures.
The functional carbonate group is -O-CO-O-.
It is widely injection-moulded to make astronaut helmets, aircraft interiors, baby bottles, battery cases, blank screens, bus windows,
citrus juice bottles, compact disks, cutlery, dental sealants, eye wear, fire masks, five gallon water bottles, helmets, injection moulded
battery cases, lining of tin cans, milk jugs, office equipment, oven baking bags, packaging, parts of cars, riot police shields, reusable
water bottles, safety glasses and goggles, safety windows, sippy cups, snow boards, spectacle lenses, sunglasses, traffic signs.
The trade names include, "Lexan", "Makrolon", ("CR39"), Columbia Resin 39, sunglasses, spectacle lens.

Bisphenol-A
Bisphenol-A, (BPA), epoxy resin polymer, is used to make polycarbonates as a commonly used phthalate plasticiser, that can leach
into the environment when heated.
Bisphenol-A is suspected of being a hormone blocker with multiple health effects including miscarriages, reduced sperm count and
cancers.
In some countries, baby bottles and sippy cups made from polycarbonates are banned.
Bisphenol-A, (BPA), (CH3)2C(C6H4OH)2, is used in thermal imaging paper, polycarbonate containers, reusable water bottles, and
metal-based food and beverage containers.
However, the use of bisphenol-A, (BPA), for containers is banned for use in baby bottles in the European Union, France, Denmark,
Canada, some US states, and Australia, because it may slowly dissolve in the contents and affect foetal brain development and be an
endocrine disrupter affecting the reproductive system.
Canada was the first country to classify bisphenol-A as a toxic substance.
Commercial: Serving jugs, polycarbonate, 2000 mL
Polycarbonate cutlery, heavy duty and re-usable, suitable for industrial and prison use, soup / dessert spoon, pack / 12

3.7.11 Polycaprolactone, PCL
"Thermoplastic Polymer", polycaprolactone (commercial)
Biodegradable polyester, [-O-(CH2)5-Ć=O] used in resins, splints and modelling.

3.7.12 Polychloroprene
Polychloroprene, neoprene, elastomer, synthesized by polymerization of chloroprene, chloropene isomer, synthetic
resists weather, (electrical insulation, car fan belts, wet suits, boats)
Neoprene, (polychloroprene), was the first synthetic used in industry.
The monomer is 2-chlorobuta-1, 2-diene, when vulcanized is very resistant to oils, chemicals, sunlight, ozone, and heat.
Chloroprene, C4H5Cl, 2-chloro-1, 3-butadiene, CH2=CCl-CH=CH2
Neoprene polymer, Elastomeric polymers and copolymers from chloroprene

3.7.13 Polychlorinated biphenyls, PCBs
PCBs, Dioxins, Agent orange: 16.14.0
Polychlorinated, biphenyls, BCBs, carcinogenic, fluorescent battens, Not permitted in schools
PCBs are mixtures of 100 of 209 possible variants, called congeners, based on biphenyl, produced commercially in the 1970s.
Australia banned the importation of PCBs in 1975.
PCBs are toxic, persist in the environment and animals, bioaccumulate through the food chain and pose a risk of causing adverse
effects to human health and the environment.
They are still being detected in human milk.
They were used as coolants and lubricants in electrical equipment, e.g. transformers, hydraulic fluids, paint additives, carbonless copy
paper, plasticizers and dye carriers.
They do not burn easily and are good insulators.
They are synthesized from biphenyl, (C6H5C6H5), and chlorine and have the general formula: C12H10.nCln (n = 1-10).

3.7.14 Polyesters
See diagram 16.3.4.8: PET
RC=O(OH) + HOR' --> RC=O(OR')
carboxylic acid + alcohol --> ester + water
Let X and Y = unspecified organic groups, e.g. -(CH2)n, -CH3.
Polyester polymer is a generic name for fibres from polyesters >85% terephthalic acid and ethylene glycol units.
A polyester has the ester link, -COO-, repeated using diols, HO-X-OH, which have two -OH groups and dicarboxylic acids,
COOH-Y-COOH, which have two carboxylic acid groups, -COOH.
C=O(OH)YC=O(OH), where X and Y, usually, = -CH3.
HO-X-OH + (OH)C=OYC=O(OH) --> -O-X-O-C=OYC=O + H2O
diol + dicarboxylic acid --> polyester unit + water
Polyesters are made from many different starting materials.
Unsaturated polyesters are viscous yellow liquids that set with catalyzer addition.
Their strength, flexibility and rigidity can be modified with additives or reinforcements, which are usually carbon or glass fibre.

1. Polyester synthetic fibre, UP, thermoset plastic, is synthesized from condensation reaction of polyhydric alcohol, e.g. monoethylene
glycol with a polybasic acid, e.g. terephthalic acid, or dimethylterephthalate, to form ester link, [ester bond, -CO.O-]

2. Linear polyester fibre are unsaturated polyester resins, synthesized from dicarboxylic acids.
They are used for glass fibres "fibre glass", reinforced tanks, kiosks, boats, casing resins, film base)

3. Polyester is a thermoplastic elastomer.
It is synthesized from polytetramethylene ether glycol and polybutylene terephthalic.
It is used for moulded items. [Polyester is not the same as acrylic.]

4. Polyesters include polyethylene terephthalate, polybutylene terephthalate (PBT), acrylic s, polyester thermoset resins.

5. Reinforced polyester is used for most pleasure boats and are used for minesweepers, surveillance vessels, buses, trains and caravans.

6. Polyester unsaturated polymers are thermosets from maleic acid / ethylene glycol polymers cross-linked with polystyrene
Examples: Polyethylene terephthalate PET a semi-aromatic copolymer, Terylene, Crimplene, Dacron, Trevira.

3.7.15 Polyethers
Polyethers, long chain glycols made from ethylene oxide, used for antistatic and emulsifying agents, e.g. PTMEG,
polytetramethylene ether-glycol.

3.7.16 Polyethylenes
Polyethylenes, polyethenes, PE, polyisobutylene, (Trade name, Polythene), thermoplastic
Laboratory plastic ware products, "Scientrific", (commercial website)Poly(ethene), polythene, alkathene, (monomer H2C=CHR,
where R = -H).
Polyethylene polymer is made by addition polymerization of the monomer ethylene, (ethene, CH2=CH2).
Polyethylene, PE, polythene, polyethene, polymethylene), (ethylene, ethene monomer), used for plastic bags, has different densities
with different functions
See 3.5.3, Plastics recycling code, Low density polyethylene, 4 LDPE, High density polyethylene, 2 HDPE
If R-O-O. = a free radical initiator
R-O-O. + CH2=CH2 --> R-OOCH2-CH2
R-OOCH2-CH2 + CH2=CH2 --> R-OOCH2-CH2-CH2
R-OOCH2-CH2-CH2 + CH2=CH2 --> R-OOCH2-CH2-CH2-CH2-CH2
Final product, polyethylene, (CH2)n, a linear high density compound.
Polyethylene, low cost, easy manufacture, tenacity and flexibility at low temperatures, it is odourless, transparent and a good insulator.
Polyethylene is used for bottle crates, bottles, bin liners, film and sheeting, toys, garbage bins ["Wheely bins"], electrical insulators,
laboratory wash bottles, moulded and extruded objects, greenhouses, packaging film, pipes, plastic bags, protective film, pressure
pipes, toys, tubing.
Polyethylene has a waxy feel and is acid resistant.
Polyethylene, (LDPE), is opaque, white, soft, flexible, impermeable to water vapour, unreactive towards acids and bases, absorbs oils
and softens, melts at 100 to 125oC, does not become brittle until -100oC, oxidizes on exposure to sunlight, subject to cracking if
stressed in presence of many polar compounds.
The range of unbreakable plastic kitchenware with airtight lids, called "Tupperware" is made of injection-moulded polyethylene.

3.7.17 LDPE
LDPE
is the plastic identification recycling code 4 for low density polyethylene used for aerosol caps, ball pen ink tubes,
disposable pipettes, freezer plastic bags, lemon juice containers, plant pots, polyethylene film, plastic tubing, "plastic lumber",
e.g. fence posts., sauce squeezing containers, shrink wrap and garment bags that may be washed and pelletized to be recycled as
plastic rubbish bags.

3.7.18 HDPE
HDPE is the plastic identification recycling code 2 for high density polyethylene bottles called "natural" because of its natural
colour that can be recycled in different colours or if already a mixture of colours can be dyed black, pelletized and injection moulded to
make aerosol caps, cable coverings, carrier bags, cereal box liners, detergent bottles, flower pots, garbage containers, injection
moulding wire, motor oil containers, non-food containers, piping, plastic bags, plastic pipes, shampoo bottles, yoghurt cups.
HDPE is a relatively safe plastic and can be used for food and drink containers of milk and fruit juices and containers of household
cleaners and chemicals.
Polyethylene, (HDPE), is similar to LDPE, but is more opaque, denser, mechanically tough, more crystalline and rigid.
HDPE shrinks more when cooling in the mould.

3.7.20 Terylene polymer
It is formed by condensation of terephthalic acid + ethan-1, 2-diol to form a straight-chain polymer fibre.

3.7.21 Polyhydantoin
It is a plastic with aliphatic and aromatic rings in the main chain
It is heat resistant and is used in insulating film and wire
enamel in electric motors.
Polyparabanic acids polymer has similar properties.

3.7.23Polymethanal
Polymethanal, is synthesized from methanal by evaporation of methanal solution

3.7.25 Polyolefins
Polyolefins, polyalkanes, hydrocarbon polymer
Polyolefin fibres are long chain polymers of ethylene, (polyethylene) or propylene, (polypropylene, PP)
Polymers formed from olefin monomers, e.g. polyethylenes, polypropylenes, and poly(4-methylpent-1-ene), a transparent brittle plastic
liable to cracking.
Polyolefin fibres are used in textiles.

3.7.26 Polyphenylenes
They are heat-resistant polymers formed from chains of linked benzene rings.
Polyphenylene oxide, PPO, [poly-(2, 6-dimethyl-p-phenylene ether], usually blended with polystyrene to form "Noryl" plastic.
Polyphenylene sulfide, PPS, has linking group -S_ in main chain, extremely heat-resistant and fire-resistant but brittle, so used in plastic
moulded parts of motor vehicle engines.

3.7.27 Polypropenes
Polypropenes, PP, polyprene, polypropylene, thermoplastic, synthesized from propylene, (C3H6)n
Models, organic, Polypropylene, 40 atoms + links, , "Scientrific", (commercial website)
Laboratory plastic ware, "Scientrific", (commercial website)3.5.3
See 3.5.3: Plastics recycling code, Polypropylene, 5 PP
Poly(propene), polypropylene, (monomer H2C=CHR, where R = -CH3).
Polypropene, the "youngest" plastic discovered in 1954, is made from the monomer propene (propylene)
Polyprene is a thermosetting, thermoplastic with repeat unit, -CHCH3=CH2.
Compared to polyethylene it has a slightly lower density, and greater rigidity and is harder.
It is the most rigid of the polyolefine polymers and maintains its rigidity up to 100oC.
It is very resistant to abrasion and heat, has good dielectric and insulating properties, it has a special resistance to being repeatedly
folded, (10 million flexions).
Polypropene is used for bottle caps and tops, bottles, bowls, buckets, car battery housings, carpets, chairs, clouded plastic containers,
crates, drinking straws, electrical appliances, fibres, (ropes), films, food containers, food wraps, heavy duty bottles, medical applications,
medicine bottles, moulding materials, parts of cars, piping, plastic buckets, road signs, sheets, take-out, ("take-away") containers, toys,
tubing connectors, non-stick surfaces of frying pans and non-lubricated bearings, non-stick cooking pan lining, gaskets,
chemical-resistant films.
Polypropylene is opaque, high melting point, (160-170oC), high tensile strength and rigidity, lowest density commercial plastic,
impermeable to liquids and gases, smooth surface with high lustre.
Low density polypropylene that is not commonly recycled except in tests.
Australian banknotes are made from biaxially-orientated, (stretched two ways), polypropylene, so parts of these banknotes are
transparent.

3.7.28 Polypropenonitrile
Polypropenonitrile is used to make acrylic fibres in Orlon knitted fabrics, imitation fur and carpets, acrilan textile fibres.
SAN
Mixed polymer SAN is made from styrene and isacylonitrile and is used for latex paints and plastic plates.
SAN, is generic name for mixed polymer styrene and acronitrile, (latex paint, plastic plates).
ABS

Mixed polymer ABS, is the generic name for plastics made from acrylonitrile, butadiene and styrene units.
Thermoset plastic for tenacity, crash resistance, hard surface, furniture, telephone sets, car parts, shoe soles, television sets.

3.7.29 Polystyrene polymer, PS
polyphenylethene, styrene, styrofoam, thermoplastic
Models, organic, Polystyrene, 48 atoms + links, "Scientrific", (commercial website)3.5.3
3.5.3 Plastics recycling code, Polystyrene, 6 PS
See diagram 16.3.4.2: Styrene, polystyrene
Styrene, ethenylbenzene, vinylbenzene, phenylethene, C6H5CH=CH2, colourless, oily liquids, noxious odour at low concentrations,
poses multiple health risks judging by research with animals.
Phenylethene polymerizes to form poly(phenylethene), polystyrene, styrene.
Styrenes are used for "rigid foams", moulded objects, electrical insulation.
Poly(phenylethene), polystyrene, (monomer H2C=CHR, where R = -benzene).
Phenylethene polymerizes to form poly(phenylethene), polystyrene, styrene.
Polystyrene, PS, does not degrade so causes widespread pollution, but it can be recycled.
Polystyrene polymer, (polyphenylethene), is made from the monomer phenylethene, (styrene), Styron thermoplastic, Styropor cellular
thermoplastic.
It can be injected, extruded and blow moulded.
Polystyrene is used for Aspirin bottles, ball pens, balls for atomic models, coat hangers, compact disk (CD) cases, cutlery, disposable
ups, plates and bowls, and cutlery, disposable Petri dishes, electrical insulation, electronic housing, foam packing materials, foam food
containers, heat insulation, insulation, meat trays, medical products, moulded objects, plastic egg cartons.
Commercial styrene contains a stabilizer that must be removed by shaking the liquid with sodium hydroxide solution before starting
polymerization.
To initiate polymerization use lauroyl peroxide instead of benzyl peroxide, because it is less toxic.
Limit experimental activity to < 2 g per activity per person or group.
Also, (polystyrene-butadiene-styrene), elastomer exists.
Polystyrene can leach styrene to the environment from land fills, smoke, car exhaust fumes and building materials.
Polystyrene foams are good thermal insulators suitable for building insulation, e.g. "Styrofoam", "rigid foams".
It is a cellular plastic from polystyrene.

EPS
EPS, expanded polystyrene, is a rigid closed-cell foam made of pre-expanded polystyrene beads for building insulation, packing
fragile items inside boxes, fast food packaging meat packaging trays and egg boxes.
The rigid panels are known as bead board.

Lustron polymer, Thermoplastic polystyrene.
Thermoplastic polystyrene, solid protective packaging, take-out, ("take-away") containers, throwaway utensils, toys, toys, yoghurt
containers.

3.7.30 Polysulfides
Polymers with linked sulfur atoms in the main chain, -S-S-, as viscous pre-polymer fluid used to seal joints in building construction,
vulcanized to form fuel-resistant plastics for lining aircraft fuel tanks.

3.7.31 Polysulfones
Polymers with aromatic links in the main chain and using sulfonyl functional group, -SO2-, non-crystalline and transparent, heat-resistant
uses, e.g. microwave ovens.

3.7.32 Polytetrafluoroetheylene, PTFE
Polytetrafluoroetheylene, PTFE, thermoset, synthesized from tetrafluoroethene, fluorocarbon resin, Teflon
Fluorine compounds: 4.0
Tetrafluoroethylene, Polytetrafluoroethylene, (PTFE): See diagram 3.4.2
1. Tetrafluoroethylene, (heat-resistant surfaces, gaskets, insulation, coating for bearings because low coefficient of friction, moulding
material, non-stick frying pan coatings, chemical-resistant film).
However, some people report that if a canary or other small caged bird is situated near a Teflon-coated frying pan heated to high
temperature, the canary dies from the gases given off by the non-stick surface, polytetrafluoroethene.

2. Polytetrafluoroethene polymer, (PTFE), the monomer tetrafluoroethene, (TFE), Repeat unit: -[CF2=CF2]n-, C2F4, heat-resistant
and chemically inert.
Trade names, "Teflon", "Fluon".
Polytetrafluoroethylene has self-lubricating and anti-friction characteristics, which make it ideal for industrial gearing, surgical prostheses
and cooking utensil coating. It is also used for pumps, valves, filters and space vehicle components.
Commercial
Poly(tetrafluoroethylene), powder, (free flowing), 1 μm particle size, fluorinated polymer, fluoropolymer, PTFE

3. Polytrifluorochloroethylene, PTFCE, is similar to PTFE but it can be injection moulded.

3.7.33 Polytetramethylene ether glycol
Polytetramethylene ether glycol, PTMEG, low molecular mass, prepolymer used to fabricate polyurethanes and polyester
See diagram 16.3.4.10: Polyurethane

3.7.34 Polyurethanes
Polyurethanes, PUR, (PU), "urethanes", (synthesized by repeating urethane group, (carbamate), -NH-(C=O)-O-,
poly-formaldehyde, (some are thermoset plastics)
See diagram 16.3.4.10: Polyurethane
Polyurethanes, (some thermosets, thermoplastic, elastomers), synthesized from isocyanates, polyols, are made with the polyaddition of
isocyanates and polyhydric alcohol.
They can be rigid or flexible so have many applications, can replace wood or leather and are good thermal and electrical insulators.
Polyurethanes form tough materials and are used for casting polymer for shaped products, car body parts, foam, tough linings,
paints, foam plastics, sports articles, furniture, mattresses, foam insulation in buildings and refrigerators, (polyurethane foams),
fibres, durable paints, varnishes, adhesives.
Molecules containing the isocyanate group, -NCO, can react with molecules containing an -OH group to give a urethane, which is
similar to the amide bond in nylons.
Heated polyurethanes produce unpleasant vapours that may contain nitric acid, HNO3, nitrogen dioxide, (NO2) and hydrogen cyanide,
(HCN).
So a burning pillow made of polyurethane foam may produce dense toxic fumes.
Polyurethanes can be formulated to make plastics with either low or high glass transition temperatures for the packaging industry and
shoe soles.
Polyurethane adhesives, surface coatings, e.g. hexamethyl diisocyanate, HMDI, irritants

3.7.34.1 Memory foam
Memory foam, temperafoam, spring back foam, viscoelastic polyurethane foam, (low resilience polyurethane foam), low
density, polyurethane + chemicals, softened by body heat, moulds to shape of body, then returns to former shape.

3.7.35 Polyvinyl acetal resins
Polyvinyl acetal resins, also similar compounds, polyvinyl formal, polyvinyl butyral, (PVB), a polyvinyl ester with ester
groups, -CO-O-, replaced by hydroxyl groups, -OH, then acetal groups, OR1RHOR1.
Acetal resins, one of the most resistant rigid thermoplastic materials, high elasticity, tenacity, resistance to stress, white translucence,
(like Nylon), used to make technical parts, e.g. in videocassettes, carburettors, zips.

3.7.36 Polyvinyl acetate
Polyvinyl acetate, polyvinylacetate, PVAC, "PVA"
See diagram 3.4.2: Vinyl acetate, polyvinyl acetate (PVA)
Polyvinyl acetate, polyvinylacetate, PVAC, (but also called PVA), poly(ethenyl) acetate, PVA but better would be PVAC so as not to
confuse it with polyvinyl alcohol, [C4H6O2, CH2CHCOOCH3], butan-2-yl acetate, thermoplastic, synthesized by polymerizing vinyl
acetate, used in adhesive glues, wood glue, white glue, school glue, and in carpentry.
Commercial: Adheseal PVA glue, general purpose woodworking glue, 2 litre container, 4 litre container

Polyvinyl alcohol, PVA, PVOH, synthetic polymer, (C2H4O)x, used in adhesives, textile size, synthetic fibres
"Colour Changing Putty", heat sensitive putty, PVA, (polyvinyl alcohol), (commercial)

3.7.37 Polyvinyl chloride
Polyvinyl chloride, PVC, polychloroethene, thermoplastic, synthesized from vinyl chloride, [CH2.CHCl]
Models, organic, Polyvinyl chloride, (PVC), 10 C atoms, 10 H atoms, 5 Cl atoms, "Scientrific", (commercial website)
See 3.5.3
: Plastics recycling code, Polyvinyl chloride, 3 V | See 16.14.0: Dioxins, Agent orange, polyvinyl chloride
Phthalates: 3.0.4
Poly(chloroethene), PVC, polyvinyl chloride, (monomer H2C=CHR, where R = -Cl).
Polyvinyl chloride polymer [(CHCl.CH3)n] is made from the monomer is vinyl chloride, (chloroethene), [CH2=CHCl]. PVC is used for
artificial leather, building materials, e.g. bottles for mineral water, fruit squash, cooking oil, shampoo and baby care products, cladding
or siding, cable covering, cling film, clothing, flooring, food packaging trays, furnishings, garden hose, gramophone records, pipes, plastic
tubing for burners, plastic wrap, rain coats, ring binder covers, shampoo containers, sheeting, swimming pool liners, take-out,
("take-away") containers, toys, upholstery, vinyl water bottles, wrist watch straps.
It is impossible to describe all its applications, which include rigid, elastic and spongy goods.
Polyvinyl chloride, (PVC), is rigid, thermoplastic, impervious to oils and most organic materials, transparent, high impact strength.
PVC may contain and leach to the environment dangerous chemicals, e.g. Bisphenol- associated with carcinogens, hormone blockers
and other health effects.
Phthalates: 3.0.4

3.7.38 Polybenzimidazoles
Polybenzimidazoles, PBI, polybenzimidazole synthetic fibre
They have aromatic heterocyclic structure, Tg > 400oC
Polyester thermoset resins are formed by polymerization of polyhydric alcohols with polycarboxylic acids or anhydrides, e.g. starting
with maleic acid and fumaric acid with ethylene and propylene alcohol, polymerized with styrene and reinforced with glass fibres,
stiffened with phthalic anhydride, to make boat hulls, canoes, car body panels.

3.7.39 Polyether ether ketones
Polyether ether ketones, PEEK, colourless thermoplastic, have benzene rings linked by linked by ether (-O-) and ketone
(-CO-) groups to form tough flame-resistant thermoplastics in aerospace construction.

3.7.40 Polyimides, PI
Functional group: -CO-NR-CO- or CO.(N).CO-), thermosetting, (heat-resistant coatings, flexible cables, electronic circuitry, adhesives)
Polypyromellitimide, heat-resistant film, trade name "Kapton".
See Imides, imido group: (-CONHCO-), (R1CO-NH-COR2): 16.1.5.8

3.7.41 Polymethylpentene, PMP
Polymethylpentene (PMP) beakers with the transparency of glass, excellent chemical resistance and remarkable heat tolerance, so they
can be used continuously at 150oC or intermittently at 175oC.
Easy to read silk-screened graduations, size code, maximum use temperature and no flame symbol, i.e. don't use on hot plates.
Non-wetting plastic ensures easy reading as there is no confusing meniscus.

3.8.1 Silicones
Silicones, thermoplastic, elastomers, synthesized from silicon, methyl chloride, polymeric unbranched siloxanes, formula
(-OSiR2-)n (R not equal to H), (oil, resins, pastes, casting moulds, cable sealant, impregnating materials, silicone grease, high vacuum
grease.
"Volasil" is octamethylcyclotetrasilocane.
The silicone polymer in "Silly Putty" is polyborosiloxane.
The term "silicone polymer" is a generic name for polymers with a siloxane chain.
Silicones: polymeric unbranched siloxanes, Formula: (-OSiR2-)n, (R not equal to H)

3.8.5 Amino-plastics
Amino-plastics, amino resins, urea-formaldehyde, (UF), melamine-formaldehyde, (MF)
Used in baking enamels with alkyds to increase hardness, colour, and resistance to chemicals.

3.8.6 Aniline-formaldehyde resin
Thermoset plastic. Aniline hydrochloride solution added to aqueous formaldehyde to form reed-like polymer.

3.8.7 Epoxy resins
Epoxy resins, e.g. Araldite, Epon, Hexion
Araldite polymer, epoxy resin, C13H18O2, an ether, (Sigma #10951), Araldite M Accelerator 960, Araldite M Hardener 964
Thermosetting epoxide polymer that cures, i.e. polymerizes and cross-links, when mixed with a hardener.
Usually made from reaction of epichlorohydrin and bisphenol-A.

3.8.8 Glycerol-phthalic anhydride
Glycerol-phthalic anhydride is formed by heating phthalic anhydride with equal volume of glycerol to form a clear plastic.
Can also use any oil or fatty acid or some resins.
Thermoset plastics

3.8.9 Melamine-formaldehyde
Melamine-formaldehyde, thermosetting plastic, melamine resin, made from melamine + formaldehyde, e.g. Melmac, Formics.
Used in counter tops, cooking spoons, kitchen bowls and plates, but are not microwavable.

3.8.10 Phenolics
Phenolics, phenolic resins, phenol-formaldehyde resins, cresol-formaldehyde resins, melamine-formaldehyde resins, (Formica, electrical
insulation, laminates, tableware)
Bakelite thermoset from phenol and formaldehyde
Phenol-formaldehyde resins, "Bakelite" the first polymer, developed by L. H. Baekeland, patented 1907, oldest thermosetting resin.
Used to make electric plugs, saucepan handles, industrial electrical components, parts of cars, radio and televisions parts, telephones.

3.8.11 Urea-formaldehyde
Urea-formaldehyde, (urea-methanal), thermoset resin, urea resins
See diagram 16.3.4.6: Urea-formaldehyde methanal condensation polymerization
See diagram 16.3.4.9: Urea-formaldehyde polymer, melamine-formaldehyde
Urea-formaldehyde resin is thermosetting, low cost, has pale colour so it can be dyed, is non-inflammable, and is used in fibre glass and
adhesives.
It is sold as a fine white moulding powder with α-cellulose, (wood pulp), filler to be used in compression moulding in a die with heat.
These resins are less water-resistant and less heat-resistant than the phenol-formaldehyde resins.
If melamine is substituted for urea, the melamine-formaldehyde resin can withstand temperatures above 100oC and is used for
light-coloured dinner ware.
They are used in adhesives and as a moulding material for electrical appliances, furniture, pans, telephones.
Condensation polymerization with the elimination of water polymer,
(NH2).CO.(NH2) + CH2O ---> NH-CO-NH-CH2 + H2O
urea + formaldehyde ---> urea-formaldehyde

3.8.12 Vulcanized fibre
Vulcanized fibre, thermosets, horn-like, synthesized from regenerated cellulose, (suitcases, gaskets, skis, strengthen wood
lamination as sublaminate)

3.8.14 Rayon
Rayon polymer, viscose fibre, artificial silk, artificial fibre, generic name for fibres from regenerated cellulose.

9.1.0 Extrusion
This continuous process is used for the production of semifinished goods such as films, sheet profiles, tubes and pipes, and sheathing of
cables.
The goods are called "semi-finished" because they must be further processed before they become useful articles.
The thermoplastic raw material for the extruder is supplied as, a powder or in granule form.
The screw turns in the heated cylinder and forces the material forward while it compacts, plasticizes, (melts), and homogenizes it.
A die is placed at the end of the cylinder that moulds the emerging plastic mass into the desired shape of pipe, sheet or other form.
The operation is, in principle, the same as that of a meat mincer with the addition of heaters in the wall of the extruder and the length of
the deeply cut screw of the extruder is much greater than that of the mincer screw.

9.2.0 Injection moulding
This process is very widespread because it can produce mouldings of high quality and with great accuracy, generally without requiring
any further work.
It is used predominantly for thermoplastics but smaller amounts of thermosets and elastomers are processed this way.
The injection moulding machine consists of an injection unit and a mould that can be opened.
The injection unit is really an extruder with a screw that can be moved backwards and forwards.
It works by plasticizing the material as the screw rotates and moves backwards and then forces the molten material out into the mould
as the screw is driven forward.
Injection moulding machine
The mould is closed and its cavities are filled with the molten plastic injected by the screw.
Feed --> Plasticisation --> Drive --> Injection and cooling under pressure --> Ejection

9.3.0 Blow moulding
The process is used for moulding hollow articles in thermoplastics.
An extruder forces the plastic tube vertically downwards between the two halves of an open two part mould.
The closing of the mould squeezes an air-tight seal at the top and the bottom, then compressed air is blown into the plastic tube forcing
out against the wall of the mould cavity while it cools to form a hollow article, e.g. a bottle.

9.4.0 Rotational moulding
This process is simple in concept.
Heat is used to melt and fuse a plastic resin in a closed mould.
No pressure is involved.
The three stage process includes loading the resin in the mould, heating and fusion of the resin and cooling and unloading the mould.
After the charged mould is placed in an oven, the mould is rotated on two axes at low speed.
As heat penetrates the mould the resin adheres to the inner surface until it is completely fused.
The mould is then cooled by air or water spray, or a combination of both, while still rotating, lowering the temperature gradually.
The mould is opened, the finished part removed and the mould is recharged for the next cycle.
Rotationally moulded products include shipping drums, storage tanks and receptacles, material handling bins and fuel tanks.
Consumer products include furniture, light shades, toys, surfboards and marine accessories.

9.5.0 Calendering
The calender produces semi-finished goods in sheet form.
Applications include brief cases and school satchels, awnings, coverings, occupational protective and warning clothing stationery files,
wrappings, pouches, upholstery.
They are also used in car interiors, children's and doll's prams, decorative sheeting, light fittings, wallpaper, and flooring sheeting for
garden furniture.
The most important application of this process is in the production of PVC sheeting and in the coating of fabric.
Plastics that melt to a low viscosity, e.g. polyethylene, are not suitable for calendering.

9.5.1 Polyvinyl chloride, Calendering
Polyvinyl chloride is continuously rolled as a semi-molten plastic between two or more rollers to give an endless sheet.
After leaving the calender, the sheet, which can be embossed during the calendering process, can be metallized, printed or surfaced with
flock by means of appropriate treatments.
The working principle involved here is similar to that of the old-fashioned kitchen mangle.

9.6.0 Foaming
See diagram 16.3.4.10: Polyurethane
The inclusion of air or gases in the structure of foamed materials reduces their density.
One method involves mixing compressed air or gas into the plastic mass, and on subsequent processing the gas is liberated and forms
a foam.
In another important method, a 'blowing agent' such as sodium bicarbonate is added to the plastic raw materials.
When the hot melt is formed the sodium bicarbonate decomposes, giving off carbon dioxide gas, which forms bubbles in the foam.
The bubbles are fixed on solidification and they confer a light density on the material.
Recently, foamed materials have become more and more important in trade and industry, not least because so many polymers can be
expanded in the ways mentioned.
They include polyethylene, polystyrene, polyvinyl chloride, (PVC), phenolic, urea, epoxide, polyester, and polyurethanes in rigid and
flexible forms.
Plastics foams can be manufactured not only by special methods but also by injection moulding, extrusion and calendering.

Zylon PBO fibre
Zylon PBO fibre is composed of rigid molecular chains [poly(p-phenylene-2, 6-benzobisoxazole)].
These fibres and filaments are characterized by high tensile strength, higher than steel), excellent impact energy absorption, and
exceptional thermal stability.
Zylon PBO fibre is available in chopped fibre, staple fibre, spun yarn, and continuous filament.
It is used in police body armour.