Polymers

Thermoplastics are held together with small cross-links, which are held together by mutual attraction. When a thermoplastic is heated it becomes pliable and soft and when it cools it goes hard again. It can be heat and shaped an infinite amount of times.

Acrylic

• Stiff, hard, durable
• Easily scratched, good insulator
• Brittle

HDPE

• Good insulator
• Chemical and impact resistant, flexible
• Colour fades, can break under stress

LDPE

• Good insulator, chemical resistant, flexible
• Colour fades, can break under stress

PET (Polyethylene terephthalate)

• Good alcohol and oil barrier
• Chemical and high impact resistant
• High tensile strength

PVC (Polyvinyl chloride)

• Good chemical and weather resistance
• Stiff, tough, hard, lightweight
• Brittle over time, UV causes brittleness

PP (Polypropylene)

• Light, hard, impact resistant, chemical resistant
• UV causes degradation
• Oxidation is a problem during manufacture

PS (Polystyrene)

Compressed

• Light, hard, stiff, brittle
• Low impact strength
• Weak, ignites easily

Expanded

• Buoyant, lightweight, good insulator
• Crumbles and breaks, ignites easily

ABS (Acrylonitrile butadiene styrene)

• Chemical resistant
• Hard, tough
• UV light causes degradation

Unlike thermoplastics, thermosetting plastics once formed cant be reheated and changed. They are covelently bonded, this makes them have a very rigid structure.

Epoxy Resins

• Corrosion and electrical resistant
• Good bond qualities
• Can cause allergic reactions, suspected health problems

Urea Formaldehyde

• Strong, hard, brittle
• Heat resistant
• Can emit toxic vapours during manufacture

Polyester Resin

• Good electrical insulator
• Heat resistant
• Brittle, can crack