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 2 3 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 formation of terminal double bonds were residence time, silane concentration, and peroxide concentration. The experimental results have shown that melt-phase hydrosilylation of polypropylene can be accomplished through this noncatalytic free radical method.

Funcionalização do Polipropileno com Viniltrietoxisilano em Solução e no Estado Fundido

“…Uma reação de hidro-sililação foi proposta por Sheares [37] para a funcionalização do PP com um hidrosilano. Segundo os autores, na reação entre PP, hidrosilano e peróxido no estado fundido, inicialmente o iniciador promove a quebra da cadeia polimérica, produzindo terminações olefínicas às quais, posteriormente, se adicionam radicais silila, através de um mecanismo de adição radicalar.…”

Radical grafting of polar monomers onto polypropylene by reactive extrusion

“…In the case of acrylic acid, grafting is accompanied by homopolymerization 29. Other polar monomers such as unsaturated carboxylic acid derivatives and vinyl or acrylic substances containing more than one functional group have also been investigated 25, 39, 43–59. Coagents like styrene were used to assist the PP radical functionalization and also to reduce molar mass decrease during grafting 57, 60–63.…”