1.3- Benzenedicarboxylic acid, polyesters from

Just as diacids and diamines react to give polyamides, diacids and dialcohols react to give polyesters. The most industrially important polyester, made from reaction of terephthalic acid (1,4-benzenedicarboxylic acid) with ethylene glycol (1,2-ethanediol), is used under the trade name Dacron to make clothing fiber and under the name Mylar to make plastic film and recording tape. 

Among polyesters synthesized from 1,4-benzenedicarboxylic acid and aliphatic diols, poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT) are the most frequently applied ones. Hydrolysis is evidently the easiest chemical recycling technique of polyesters, however they may be mixed with other waste plastics, thus it is useful to know the properties of their pyrolysis product. 

Dacron, a popular polyester fiber, is woven from polymer strands formed when equimolar amounts of 1,4-benzenedicarboxylic acid and 1,2-ethanediol react. Blending these polyester fibers with various amounts of cotton gives fabrics that are durable, easily dyed, and crease resistant. Extremely thin Mylar films, used for recording tape and food packaging, are also made from this polymer. 

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