Reinforcement of Fluoroelastomers with Halopolymers

Abstract

Abstract This study demonstrated the utility of Teflon as a reinforcing agent. Elastomeric compositions prepared with Teflon powder by milling or extrusion have very large increases in tensile strength when measured parallel to the direction of shear, and high tear strength when measured perpendicular to the direction of shear. Teflon powder sheared in a fluoroelastomer matrix coalesces to form fibrils. The hypothesis that free radicals, and therefore branching, are produced when Viton and Teflon mixtures are sheared at ambient temperature is supported by the increase in slope of curves of ηsp/c as a function of c. However, the principal cause of the large improvement in tensile and tear strength is believed to be formation of oriented Teflon fibers and films in the elastomer matrix. The formation of these fibers and films would explain the rough surface of milled material as well as the poor consolidation of these materials when they are compression molded. Reinforcement by fibrillation does not occur with Kcl-F resin or fluorinated ethylene propylene.