Methyltrimethoxysilane plasma polymerization coating of carbon fiber surfaces

Abstract

The adjustment of carbon fiber surface properties represents an important aspect to improve the adhesion behavior and the stress transfer between carbon fibers and polymeric matrices in carbon fiber reinforced polymers. In the presented work the surface of continuous carbon fiber tows composed out of 50,000 single fibers, so called 50k tows, is modified by an atmospheric plasma jet treatment of combined plasma activation and plasma polymerization, to improve adhesion to an epoxy matrix. Methyltrimethoxysilane is used as precursor gas to deposit a silicon organic layer. The developed experimental setup allows stable plasma treatment of more than 1200m of 50k carbon fibers, which were shown to be textile processable, and thus represents a promising route for surface treatment of carbon fibers for composite production. Largely homogeneous plasma deposition along and across the 50k carbon fiber tow is demonstrated by chemical surface analysis and high resolution microscopy. Single fiber mechanical properties are preserved under the plasma treatment.