Chemical Modification of Polypropylene by Decomposition of Unsaturated Peroxides

Abstract

Chemical modifications of polypropylene were studied via the decomposition of β,γ-unsaturated peroxides. Six peroxy derivatives were used to test the influence of the more important structural parameters (type of peroxide, nature of the unsaturation, and substituents in the allylic position) of such compounds on the efficiency of the grafting of a function and on the degradation of the polymer. Grafting of ester and epoxide functions on the chains of the polyolefin occurred with a slight degradation of these last ones with the use of acrylic peroxides. The decomposition of a styrenic peroxide allowed the grafting of phenyl entities on the backbone and induced structural modifications of the chains (branching). However, no epoxidic groups were detected in this case. Allylic peroxide did not permit any functionalization of the polyolefin but provoked some changes in the structure of the polymer. Mechanisms for the grafting and the degradation of the polypropylene were proposed.