Effect of Processing Condition on Bending Properties of Thermoplastic Composites with Commingled Supn Yarn. Longitudinal Bending Strength and Impregnation Behavior.

Thermoplastic composites have several advantages over thermoset composites in productivity and properties. However, thermoplastic composites have not been used so widely. Several impregnation techniques have been specially developed for thermoplastic composites to solve the difficulty in impregnation of their matrix resins.In this paper, we propose a new impregnating system using a commingled yarn of spun yarn, in order to facilitate the impregnation process. This yarn consists of carbon fibers and Nylon 6 fibers. We fabricated unidirectional composites using spun yarn. We performed a longitudinal bending tests and examined the influence of processing conditions on the bending properties. It was observed that the resin-rich regions between fiber bundles in composites were formed due to the original twist structure of fiber bundle. Impregnating behavior of resin was affected by processing conditions and progressed with two steps, that is, the resin firstly impregnated inside of fiber bundles and next impregnated between fiber bundles. Longitudinal bending strength was saturated at a rather lower pressure and in a shorter period of compression.