FREE-RADICAL HYDROSILYLATION OF POLYPROPYLENE

Hydrosilylation of terminal double bonds in polypropylene was investig ated via a free radical process in the melt-phase. This process involv ed the following two reactions occurring in parallel: chain scission, which leads to formation of double bonds, and the addition of silyl ra dicals to such bonds. Fourier Transform Infrared Spectrometry (FT-IR) was used to follow silane incorporation and terminal double bond forma tion. The experimental trends were verified using elemental analysis o btained from energy dispersive x-ray analysis (EDX). Using a single sc rew extruder and a model silane compound, a 2(3) full factorial experi ment design was implemented with the following investigated factors: r esidence time, silane concentration, and peroxide concentration. Stati stical analysis of the FT-IR results, showed that, for the silane inco rporation, residence time, peroxide concentration, and the interaction between the silane and peroxide concentrations had significant effect s. The significant effects for the formation of terminal double bonds were residence time, silane concentration, and peroxide concentration. The experimental results have shown that melt-phase hydrosilylation o f polypropylene can be accomplished through this noncatalytic free rad ical method. (C) 1997 John Wiley & Sons, Inc.