Polyester

Some synthetic polymers have ester group in them. These are condensation polymers.

Terelene

It is a polymer obtained by the condensation reaction between ethylene glycol and terephthalic acid.

Terelene is resistant to the action of most of the common chemicals and biological substances and also to abrasion. It has a low moisture absorbing power. It is widely used in making wash and wear fabrics. The polyester textile fibres made from the polymer are marketed under the trade name terelene or dacron. It is also blended with cotton and wool in clothing. It is also used in seat belts and sails. The polymer is also used in the preparation of films, magnetic recording tapes and for packing food. Dacron (and Teflon) tubes are good substitutes for human blood vessels in heart by pass operation.

Glyptal or Alkyl Resin

Glyptal is a general name of all polymers obtained by condensation of di-basic acids, and polyhydroxy alcohols. The simplest glyptal is (poly ethelene glycol phthalate) which is obtained by a condensation reaction between ethylene glycol and ortho-phthalic acid.

Glyptal resins are three dimensional cross-linked polymers. Poly ethylene glycol phthalate dissolves in suitable solvents and the solution on evaporation leaves a tough and non-flexible film. Thus, it is used in adherent paints and lacquers.