Polymerization Of Vinyl Monomers On Mineral Surfaces; A Novel Method Of Preparing Reinforcing Fillers

Abstract

A novel method for producing modified mineral fillers is reported: The mineral surface is first made “acidic” and this acidic surface is used to initiate the cationic polymer-ization of vinyl or preferably divinyl monomers, the residual acidic sites being subsequently neutralized with ammonia or an organic base. During compounding, grafting occurs between the encapsulating polymer layer and the matrix polymer via previously formed peroxidic groups in this layer or via radical attachment at unsaturated centers in the polymer coating. The incorporation of these modified fillers in various grades of polyethylene results in significant improvements in processability and in tensile and impact str..