Radical-mediated graft modification of polyethylene models with vinyltrimethoxysilane: a theoretical analysis

The grafting of vinyltrimethoxysilane (VTMS) onto low-density polyethylene is an important commercial process for the production of crosslinked polymer for use in the wire and cable industry. Experimentally, it has been reported that the reaction of VTMS with low-molecular-weight model hydrocarbons (polyethylene mimics) produce a variety of grafted products. While reasonable mechanisms have been proposed to rationalize the formation of this array of grafted products, the regio- and stereochemistries of the products as well as the energetics associated with each of the proposed steps in the reaction sequence are not known. In order to address these issues, a density function theory (B3LYP/6.31G*) analysis for each of the proposed steps in the grafting process is now reported.