Plastics 2 : A wide range for substances which are capable of being moulded under certain conditions, some by heat, others by pressure, etc. The two main types are thermosetting, irreversible rigid, and thermoplastic, reversibly rigid
H. J. Porter (Chairman - Technical Committee), Dictionary of Fire Technology, The Institution of Fire Engineers, The Victory Press (Leicester) Ltd. 1979 UK. (Fr Tech - Brit) {81}