Define plastic material

Plastic is a synthetic or semi-synthetic organic material made of long-chain polymers, which can be moulded into a desired shape by heat and pressure and keeps that shape on cooling or setting. Plastics are made from petroleum, natural gas or coal products with additives (fillers, plasticisers, stabilisers and pigments). They are light, corrosion resistant and cheap, and are used for pipes, sheets, tanks, flooring, insulation and fittings. They are of two types: thermoplastic and thermosetting.