Abstract: The isothermal radial growth rates of spherulites and the morphology of maleic anhydride-g-polypropylene have been determined by means of polarizing microscope. Chain segments of maleic anhydride and polypropylene in the graft copolymer are partly compatible. A change in the growth region is observed at 132℃ and interpreted as a Region Ⅲ→Region Ⅱ transition, according to the kinetic theory of compatible polymer blend crystallization. The equilibrium melting temperature (T_m⁰) of the graft copolymer was measured as 200℃, lower than that of ipp.

Key words: maleic anhydride-g-polypropylene, graft copolymer, isothermal crystallization, spherulitic growth, equilibruim melting temperature, surface energy