STUDIES ON POLYESTER ELASTOMERS - STRUCTURE AND PROPERTIES OF POLYESTER ELASTOMERS

The effects of the composition of polyester-polyester block polymers and polyester-polyether block polymers, which were prepared by the reaction of poly(1,4-butylene terephthalate) (PBT) with epsilon-caprolactone (epsilon-CL), on the structure and properties were studied by means of dynamic viscoelasticity, wide angle X-ray diffractiometry, and transmission electron micrography. Each polyester-polyester block copolymers hade one melting point and glass transition temperature. The relation between glass transition temperature and composition of polyester-polyether block polymers was explained by Gordon-Taylor's equation, but that of only the polyester-polyester block polymers containing 50-70 wt% of hard segment was explained. Polyester-polyester block polymers containing more than 40 wt% of soft segment had lower crystallinity than those of polyester-polyether block polymers. The polyester-polyester block polymer containing 75 wt% of soft segment had crystalline soft segment and amorphous hard segment. It was comfirmed that polyester-polyester block polymers had micro domain structure by means of transmission electron micrography.