Question
Tue November 01, 2011 By: Ritu Srivastava

GIVE TWO EXAMPLES OF POLYSTER AND THERE PREPARARION

Expert Reply
Tue November 01, 2011
Polyester is a term often defined as “long-chain polymers chemically composed of at least 85% by weight of an ester and a dihydric alcohol and a terephthalic acid”. Examples are Polyethylene terephthalate, polylactic acid, Vectran, Polyethylene adipate, etc. Generally polyesters are prepared through serise of condensation reactions.
 
(n+1) R(OH)2+ n R´(COOH)2 ----->  HO[ROOCR´COO]nROH + 2n H2O
Polyesters as thermoplastics may change shape after the application of heat.
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