Chapter 3 - Materials

Abstract

Plastic materials are composed of carbon and hydrogen atoms, associated with a wide range of other elements, such as chlorine, oxygen, and nitrogen. This chapter describes the two main families of plastic materials—thermosetting resins and thermoplastics. Thermosetting resins, such as epoxies, generally require heat to transform them into an irreversible three-dimensional molecular chain, whereas thermoplastic materials, such as polyethylene, become malleable as the temperature is increased, and this transformation is reversible. Both resin types can be used with fiber reinforcement or fillers to improve their mechanical properties or to facilitate a particular molding process. The thermosetting resin family includes the wide range of unsaturated polyesters (UPs) resins, the epoxies, (EPs), and the various forms of polyurethanes (Pu). Many other thermosetting resin families exist, such as phenoplasts, aminoplasts, and polyimides. Thermoplastic materials, such as polyvinyl chloride (PVC), polyethylene, and polypropylene are combined with a thermoset composite, taking advantage of the chemical and abrasion resistance of the thermoplastic material, and the mechanical strength and resilience of the composite.