Thermoplastics and thermosetting plastics

The simplest way of classifying plastics is by their reaction to heat. This gives a ready subdivision into two basic groups:thermoplastics and thermosetting plastics. Thermoplastic materials soften to become plastic when heated,no chemical change taking place during this process. When cooled they again become hard and will assume any shape into which they were moulded when soft. Thermosetting materials,as the name implies,will soften only once. During heating a chemical change takes place and the material cures; thereafter the only effect of heating is to char or burn the material.
As far as performance is concerned,these plastics can be divided into three groups:

General-purpose thermoplastics
Polyethylene
Polypropylene
Polystyrene
SAN (styrene/acrylonitrile copolymer)
Impact polystyrene
ABS (acrylonitrile butadiene styrene)
Polyvinyl chloride
Poly(vinylidene chloride)
Poly(methyl methacrylate)
Poly(ethylene terephthalate)
Engineering thermoplastics
Polyesters (thermoplastic)
Polyamides
Polyacetals
Polyphenylene sulphide
Polycarbonates
Polysulphone

Modified polyphenylene ether
Polyimides
Cellulosics
RIM/polyurethane
Polyurethane foam
Thermosetting plastics
Phenolic
Epoxy resins
Unsaturated polyesters
Alkyd resins
Diallyl phthalate
Amino resins