Abstract: By utilizing the rapid degradation reaction characteristics of polyoxymethylene (POM) under an acidic atmosphere and the corrosion resistance of polypropylene (PP), POM/PP blends were employed as a major component of catalytic skim binder for metal powder injection molding. Crystallization behavior of POM/PP blends was investigated by DSC under the non-isothermal process, and their crystallization kinetics was studied by Jeziorny, Ozawa and Mo methods. The results indicated that the width of crystallization peak became broad and the crystallization peak temperature (Tc) decreased gradually with an increase of cooling rate. Tc of the blends was lower than that of pure POM at the same cooling rate. Jeziorny and Mo methods could well describe the non-isothermal crystallization of POM/PP blending system. However, Ozawa method is not applicable due to the occurrence of secondary crystallization. Moreover, the introduction of PP led to a decrease in crystallization rate but an increase in half crystallization time. This also resulted in a change in the nucleating and growing mechanism of POM domain, thus retarding its crystallization.

Key words: polyoxymethylene, polypropylene, non-isothermal crystallization, cooling rate