A study of softening in polyester thermoelastoplastics

Abstract The thermodynamics of forced softening of polyester thermoelastoplastics based on polybutylene terephthalate and polytetramethylene oxide have been studied by deformation calorimetry. It was shown that the deformation of these systems is related to large energetic changes. The primary stretching is similar to orientational extension of solid polymers and is accompanied by significant energy absorption, the magnitude of which is determined by the rigid phase content.