Study of the thermal and viscoelastic properties of phosphorus-containing urethane block copolymers☆

A series of phosphorus-containing block copolyurethanes distinguished by the structure of the rigid blocks has been studied by DTA, thermomechanical analysis, stress relaxation on constant deformation and X-ray diffraction at low scatter angles. It is shown that the inhomogeneity of structure and flexibility of the chain of the block copolymer predetermines the development of processes of microphase ply separation which, in turn, influence the formation of the macroproperties of the block copolyurethanes. Phosphorus-containing chain elongators of rigid blocks reduce their capacity for self-association into rigid domains although by changing the structure and polarity of the other fragments of rigid blocks one may change in a directed way the character of the microphase ply separation in the system. A model of the rigid domain is proposed for the phosphorus-containing block copolyurethanes studied.