ABB105: Plastics and Stairs

PLASTICS

• Synthetic or semi-synthetic material made from polymers.

• Many parts

• Byproduct of fossil fuels

• Lightweight, durable, insulating, biodegradable, reusable.

• Thermoplastic and Thermosetting plastic

Thermoplastics

Types of plastics that can be melted and reshaped multiple times, making them versatile for various applications. Reheated, remolded, recyclable, harder, low melting point.

• Polystyrene

• Polyethylene

• Acrylic: scratch resistant, windows, translucent.

• Nylon

• Polyvinyl chloride (PVC): pipes, fittings, roof membranes, durable, inexpensive.

• Polypropylene: lightweight, heat resistant, nontoxic, common in chairs and cladding.

• Polycarbonate: lightweight

• Teflon

• Acetal copolymer polyoxymethylene.

• Composites: vinyl, fiberglass.

Thermosetting plastic

A type of plastic that, once cured or hardened, cannot be remolded or melted again. They are typically used in applications that require high heat resistance and durability, such as electrical insulators and automotive parts.

• Are not finished products, must be completed by secondary companies where hardeners are added.

• Epoxy and polyurethane.

• Synthetic adhesives such as phenol-formaldehyde and urea-formaldehyde.

• Synthetic rubbers are subgroup, with permanent elasticity.

Polyethylene (PE)

• Difficult to decompose, can be burned for energy without giving off harmful substances aside from carbon dioxide.

• Exposure to ethene may occur in work place.

• Polymerized from ethylene.

• Thermoplastic

Polypropylene (PP)

• Polymerization of propylene.

• Ultra-violet stabilizers, antioxidants and colouring.

• Exposure during manufacture is damaging.

• Difficult to dispose, burning will release carbon dioxide.

• Thermoplastic

Polystyrene (PS)

• Polymerization of styrene

• High resistance to moisture.

• Transparent sheeting and foamed expanded polystyrene (EPS) and extruded polystyrene (XPS).

• Additives: antioxidant, ultraviolet stabilizer, fire retarder.

• Production emissions of benzene, ethyl benzene, styrene, pentane and chlorofluorocarbons.

• Health effects of benzene, ethylene and styrene.

• Finished product may have unstable residues of styrene which may be released into the atmosphere.

• Damaging waste product as it can leak additives and is difficult to decompose.

Pollution

• Extraction and refining crude oil and natural gases have large impact on the environment.

• Emit damaging substances both during production and deposing.

Polycarbonate (PC)

• Thermoplastic

• Can be used for sustainable plastic building supplies

• High impact resistance and transparency.

• Used for its strength and clarity.

• E.g. glazing.

Polyvinyl Chloride (PVC)

• Widely used for plastic construction materials.

• Inexpensive & durable.

• Used for pipes, fittings, floorings, window, door and roof membranes.

• Makes up 20% of plastic.

Acrylic

• Thermoplastic

• Optical clarity, scratch resistant, rigidity.

• Used for light fixtures, LED screens and transparent sheets.

Other Thermoplastic Examples

Nylon, teflon, acetal copolymer polyoxymethylene, acetal homopolymer polyoxymethylene.