Free radical hydrosilylation of polypropylene

Abstract

Hydrosilylation of terminal double bonds in polypropylene was investigated via a free radical process in the melt-phase. This process involved the following two reactions occurring in parallel: chain scission, which leads to formation of double bonds, and the addition of silyl radicals to such bonds. Fourier Transform Infrared Spectrometry (FT–IR) was used to follow silane incorporation and terminal double bond formation. The experimental trends were verified using elemental analysis obtained from energy dispersive x-ray analysis (EDX). Using a single screw extruder and a model silane compound, a 23 full factorial experiment design was implemented with the following investigated factors: residence time, silane concentration, and peroxide concentration. Statistical analysis of the FT–IR results, showed that, for the silane incorporation, residence time, peroxide concentration, and the interaction between the silane and peroxide concentrations had significant effects. The significant effects for the forma-tion of terminal double bonds were residence time, silane concentration, and peroxide concentration. The experimental results have shown that melt-phase hydrosilyla-tion of polypropylene can be accomplished through this noncatalytic free radical method. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:439–447, 1997