Effect of injections on the orientation of short fibre composites. An optical microscopic analysis

Short fibre reinforced thermoplastic composites were studied using polyurethane as the matrix and aromatic polyamide, and carbon fibre or regenerated cellulose as the structural component. For each type of fibre, the amount was varied and mechanical properties (tensile and abrasion resistance) and optical microscopy were investigated from injected sheets. The tensile resistance results were in accordance with those observed with the surface light reflected photomicrographs. Arithmetic average values of tensile resistance for samples taken at different directions of stress were close to the values observed for injected pieces in those regions where the fibrillar arrangement in the matrix was random. In general, the abrasion resistance was also improved. Copyright (C) 1996 Elsevier Science Ltd