Textile-Integrated Elastomer Surface for Fiber Reinforced Composites

Elastomer layers offer a wide range of surface functionalization options for fiber-reinforced polymer composites (FRPC), e.g. erosion protection or increased impact resistance. Goal of this study was to investigate if it is possible to prepare a textile-based semi-finished product with elastomeric surface, which can easily be used as outermost layer in different liquid composite molding (LCM) processes. For this purpose, different types of elastomer were pressed and vulcanized onto a biaxial glass fiber fabric. Target of this procedure was to reach partial immersion of the elastomer into the textile with remaining dry textile areas. The dry areas of the textile can later be impregnated with a thermoset resin system. The strategy is to have the transition region between elastomer and thermoset within one textile layer and to give a robust and easy to handle semi-finished-product in order to achieve a maximum bonding strength of the elastomer surface to the final composite part. It could be shown by micrographs and computer tomography that the elastomer only penetrates the textile at its boundary. A remarkable microimpregnation of individual filaments within the rovings does not take place. Concerning the manufacturing, since water evaporates during vulcanization, a sufficient process pressure must be maintained throughout the entire vulcanization process to ensure a pore-free elastomer. Peel-off tests similar to DIN EN 28510-1 on the finished composite showed a failure in the laminate and not in the boundary layer between laminate and elastomer, so that the desired high joint strength could be demonstrated.