What are Plastic/Polymers?
There are two basic types of plastics/polymers: thermoplastic and thermoset. In general, FRP composites utilize a thermoset plastic.A plastic in which the polymer molecules are not crosslinked (not chemically bonded to other polymer molecules) is a thermoplastic. Since the molecules are not connected by crosslink’s, it allows the molecules to spread farther apart when the plastic is heated. This is the basic characteristic of a thermoplastic; the plastic will soften, melt, or flow when heat is applied. Melting the plastic and allowing it to cool within a mould will form the finished product. Typical thermoplastics are: polyethylene (PE)– used in making garbage bags; polyvinyl chloride (PVC)– used for house siding; and polypropylene (PP)– used as carpet fibers, packaging, and diapers. A plastic in which the polymer molecules are crosslinked (chemically bonded) with another set of molecules to form a “net like” or “ladder-like” structure is a thermoset. Once crosslinking has occurred, a
