Influence of an aqueous acetone medium on the thermal behaviour of the solvent treated poly (ethylene terephtalate).

When amorphous PET filaments are treated in acetone-water mixtures under controlled conditions, they retain amorphous properties. The Tg'S and Tc'S are lowered well below the usual values and at the same time the structure becomes swollen. Ageing the treated polymer freed from acetone results in a reversible process that gives transition values close to the values for the untreated sample; but the polymeric phase remains swollen. A combined action of primary and secondary plasticizers is proposed in this paper.