Influence of the polyethyleneglycol content on the properties of ethyleneglycolterephthalate/polyethyleneglycol terephthalate copolymers

Abstract

The effect of the polyethyleneglycol (PEG) content on the properties of the ethyleneglycol terephthalate (EGT)=polyethyleneglycol terephthalate (PEGT) copolymers has been studied. The PEG content varied over a wide range (5À70% PEG). To obtain information on the solubility and on the thermal properties, the following methods: turbidimetry, differential scanning calorimetry (DSC), thermogravimetry and differential thermogravimetry (TG, DTG) have been used. The turbidimetric characteristics are dependent on composition copolymers. The incorporation of increasing amount of PEG 4000 in EGT=PEGT copolymers has a pronounced effect on the properties: increases viscosity and solubility of copolymers, decreased glass transition, cold crystallization and melting temperatures and also decreased crystallization and melting heat. These changes are desirable for better processing of these copolymers comparatively with PET in products with higher elasticity and hydrophilicity. It must be take into account, however, that above 20 wt% PEG the copolymers the thermal stability is significantly affected.