The effect of physical parameters of isotactic polypropylene on its oxidisability measured by chemiluminescence method. Contribution to the spreading phenomenon

摘要

The physical parameters of the polypropylene powdered samples like average molar mass, the degree of isotacticity and the resulting crystallinity and melting temperature have quite an important effect on the oxidisability of polypropylene expressed in induction time of oxidation or in maximum chemiluminescence intensity. It was shown that it is the increase of both the average molar mass and the degree of isotacticity which predominantly lead to the longer induction times of oxidation while the opposite is true for maximum chemiluminescence intensity for molar mass 40,000-180,000 and temperature interval 80-130℃. The combined model of the homogeneous increase of concentration of hydroperoxides in the oxidation micro-zones and the spreading of the oxidation from these micro-zones has been proposed which fits well the experimental runs of chemiluminescence intensity time.