Spherulitic microstructure and the effect of factors on the crystallization kinetics of pure isotactic polypropylene

Isotactic polypropylene (IPP) is a useful thermoplastic with wide range of applications, due to properties such as of high tensile strength, hardness, and chemical resistance. The crystallization kinetics and morphology development of pure isotactic polypropylene at different crystallization temperature Tc it was analyzed by optical microscope with polarized light in transmission mode (POM) equipped with hot stage. It was determined nucleation and growth rates of spherulites. The number of nuclei increased and the radial growth rates of spherulites decreased with increasing the rate of super cooling ΔT. The nucleation rate was constant at a predetermined temperature in isothermal crystallization conditions and the results were comparable with the literature. The radial growth rates of spherulites depended from the crystallization temperature. It was analyzed and compared the different morphological structures of pure IPP cooled in different ways: in the water at T = 100°C, in the water T = 0°C and at T = - 10°C.