Relaxation phenomena and morphology of polyurethane block copolymers

Abstract

Five types of linear segmented polyurethanes based on a low molecular weight polyester, reacted with 4,4′-diphenylmethane diisocyanate (MDI), and extended with 1,4-butanediol (BDO), have been studied by dynamic mechanical analysis (DMA), thermally stimulated depolarization current method (TSDC), and differential scanning calorimetry (DSC). Different types of transitions and relaxations have been detected and related to the structure and morphology of the block copolymers studied.