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These flashcards review the origin of plastics, key traits of thermoplastics, their advantages, and the properties, uses, and limitations of major thermoplastic materials (Nylon, LDPE, HDPE, PET, PVC, Acrylic, PS, PP, ABS).
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From what primary raw material are most plastics produced?
Crude oil.
What two main families are plastics divided into?
Thermoplastics and thermosetting plastics.
What key characteristic makes thermoplastics so widely used?
They can be reheated and reshaped repeatedly (thermo-forming).
Give two common advantages of thermoplastics.
Any two: (1) Soften when heated, (2) Recyclable, (3) Available in many colours, (4) Safe for children, (5) Relatively cheap, (6) Compatible with processes such as vacuum forming, injection moulding and blow moulding.
Name two manufacturing processes that commonly use thermoplastics.
Vacuum forming, injection moulding, blow moulding (any two).
Which thermoplastic is hard, tough, has low friction, and is used for bearings and gears?
Nylon.
What is one disadvantage of Nylon?
Its low-friction surface can stain quickly (also has low water absorption).
Which thermoplastic is tough, flexible, chemically resistant and used for detergent bottles and carrier bags?
LDPE (Low-Density Polyethylene).
State one limitation of LDPE.
High thermal expansion and it is flammable.
what are the uses of LDPE?
Detergent and shampoo bottles, toys, carrier bags and transparent packaging
Which strong, stiff plastic is popular for crates, bowls, buckets and pipes?
HDPE (High-Density Polyethylene).
What is a key weakness of HDPE?
Sensitive to stress cracking and highly flammable.
Which transparent thermoplastic is used for drink bottles and smart cards?
PET (Polyethylene Terephthalate).
Give one drawback of PET.
Low thermal resistance or poor solvent resistance (either is correct).
Which plastic releases chlorine atoms when burning, inhibiting combustion, and is used for pipes and window frames?
PVC (Polyvinyl Chloride).
How does high temperature affect PVC?
Its strength decreases at elevated temperatures.
Which thermoplastic often replaces glass in skylights and aircraft canopies?
Acrylic (PMMA).
State one disadvantage of Acrylic (PMMA).
Prone to scratching and easily stained by grease/oil; flexible grades are not available.
Which rigid, brittle plastic with good electrical properties is used for toys, beakers and household appliances?
PS (Polystyrene).
What limits Polystyrene’s outdoor use?
Poor resistance to UV light; it becomes brittle and has low chemical resistance.
Which lightweight, food-safe plastic is common for string, rope, medical equipment and kitchenware?
PP (Polypropylene).
Why is polypropylene (PP) not ideal for long outdoor exposure?
It suffers UV degradation and is difficult to paint.
Which high-impact, durable plastic is used for mobile phone cases, toys and safety helmets?
ABS (Acrylonitrile Butadiene Styrene).
Why is ABS use limited in the food industry?
When burned it produces toxic gases such as carbon monoxide (CO) and hydrogen cyanide (HCN).
Are the listed thermoplastics biodegradable?
No; they are not biodegradable but are recyclable—except Acrylic, which is difficult to recycle.