Other amorphous thermoplastics

Abstract

Amorphous thermoplastics were some of the earliest plastics, excepting polycarbonate, to find general acceptance; indeed, cellulose plastics were the first thermoplastics available commercially, and poly(methyl methacrylate), (PMMA), was a commercial product in the 1930s. Their continued application some 50 years later is a comment on their usefulness, and on their properties compared with those of polystyrene, since PMMA is almost twice the price of PS, and the cellulose plastics are significantly more expensive than PMMA. Polycarbonate, a development of the late 1950s, is some three times more expensive than PS, and so finds use in critical applications where performance rather than cost is the criterion of acceptability. There are other amorphous thermoplastics with yet more advantageous properties which have not reached the status of commodity materials; a selection of these with elevated service temperatures is reviewed in a later chapter.