Plastics

Two main categories

Thermosetting plastics – Are heated and moulded into shapes and are very hard to mould back into their original shapes.

Thermoplastics – They will soften when they are heated, and can be shaped when hot.

Summary of plastics

. Good electrical and thermal insulators

. Good strength to weight ratio

. Generally good resistance to atmosphere and chemical erosion

. Low melting point = Less heat required therefore saving money

. Lightweight

. Available in a wide range of colours and transparency – Simply by adding a coloured pigment to the material 

Plastic names – Thermo polymers

ABS – Acrylonitrile Butadiene Styrene

CA – Cellulose acetate

Nylon – Polyamide

PMMA – Polymethylmethacrylate – Acrylic     

PP – Polypropylene

HIPS – High Impact polystyrene

PS – Polystyrene

LDPE – Low density polyethylene 

HDPE – High Density polyethylene 

Thermoset polymers

Epoxy resins – Surface coatings, encapsulation of electronic components and adhesives

Melamine – Tableware and decorative laminates

Polyester resins – Castings and used in GRP

Urea formaldehyde – Electrical fittings and adhesives