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

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 chemil uminescence intensity. It was shown that it is the increase of both the ave rage molar mass and the degree of isotacticity which predominantly lead to the longer induction times of oxidation while the opposite is true for maxi mum chemiluminescence intensity for molar mass 40,000-180,000 and temperatu re interval 80-130 degreesC. The combined model of the homogeneous increase of concentration of hydroperoxides in the oxidation micro-zones and the sp reading of the oxidation from these micro-zones has been proposed which Bts well the experimental runs of chemiluminescence intensity-time. (C) 2001 E lsevier Science Ltd. All rights reserved.