In contrast to crosslinking thermosets, whose cure reaction cannot be reversed,
thermoplastics harden when cooled but retain their plasticity; that is, they
will remelt and can be reshaped by reheating them above their processing
temperature. Less-expensive thermoplastic matrices offer lower processing
temperatures but also have limited use temperatures. They draw from the menu of
both engineered and commodity plastics, such as polyethylene (PE), polyethylene
terephthalate (PET), polybutylene terephthalate (PBT), polycarbonate (PC),
acrylonitrile butadiene styrene (ABS), polyamide (PA or nylon) and polypropylene
(PP). High-volume commercial products, such as athletic footwear, orthotics and
medical prostheses, benefit from the toughness and moisture resistance of these
resins, as do automotive air intake manifolds and other underhood parts.