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The raw materials for plastics are coal and 1_______, and many plastic materials today are produced from oil. Plastics can be divided into two main 2_______. The first group, called thermoplastics, includes well-known plastics such as PVC, nylon and polythene. These can be treated (heated, softened and cooled) several times, and can be formed into combs, pipes and bags, in addition to many other similar 3_______.
Thermosetting 4_______ include melamine, polyurethane and phenolic resin, and can be made into tableware, foams and plugs respectively. However, this group differs from thermoplastics because they can be treated only once and harden when they are heated.
oil
categories
products
plastics