ABSTRACT
The matrix used in a Polymer Matrix Composites (PMC) is either a thermosetting or a thermoplastic polymer. This chapter discusses the general processing characteristics of thermosets and thermoplastics commonly used in PMCs. The chemical reaction transforming a low-viscosity prepolymer liquid to a solid thermosetting polymer is called curing or cross-linking, which is a time- and temperature-dependent phenomenon. For some thermosetting resins, such as polyesters and vinyl esters, reactive solvents are used not only to reduce their viscosity, but also to participate in the curing reaction. Among the various thermosetting polymers used in PMCs, epoxies are known for their high strength, durability, excellent resistance to chemicals and solvents, and, in general, high performance at elevated temperatures. Polyurethanes are used in a composite manufacturing process called SRIM. The two chemicals used in the production of polyurethanes are a diisocyanate and a polyol. Polyurethanes are available as both thermoplastic and thermosetting polymers.
