The spherulite growth behaviour of hard segment has been studied by SALS and other techniques for polyester-polyether block copolymers with low hard segment content. It has been found that the growth of spherulite is determined by the competition of two factors: the rate of phase separation of the components and the rate of crystal growth. The difference in crystalline morphology has slight influence on tensile property at low draw ratio but appreciably affects tensile behaviour

including tensile strength at high draw ratio.