Polyesters
The polymers which contain an ester linkage are known as polyester , e . g ., dacron .
1 . Polymethylmethacrylate ( PMMA )
It is prepared by the polymerisation of methylmethacrylate in the presence of suitable organic peroxide .
The polymer is known by several commercial names such as lucite , acrylite , plexiglass and perspex .
Properties and uses
It is a hard and transparent polymer and is quite resistant to the effect of light , heat and ageing . It is used , in the manufacture of unbreakable lights , protective coatings , dentures , and in making windows for aircrafts .
2 . Glyptal
It is a polyester having crosslinks . It is a thermosetting plastic . It is obtained by condensation of ethylene glycol and phthalic acid or glycerol and phthalic acid .