The mechanical properties of unidirectional thermoplastic composites manufactured by a micro-braiding technique

'Micro-braided yarn' has been proposed as a means of overcoming the difficulty of manufacturing long-fiber-reinforce thermoplastic composites. Micro-braided yam is a processing material system that may be used for complex-shaped composites such as textile structural composites. In this study, unidirectional glass-fiber/PA6-Nylon composites manufactured from micro-braided yarns were molded in order to investigate the effect of the micro-braiding structure and processing conditions on impregnation and mechanical properties. The void content was determined in order to examine the quality of impregnation and this was found to decrease with increasing holding time when the pressure was applied to the preform. Axial and transverse bending tests were carried out. The axial-bending strength was well correlated with the void content. However, the transverse bending strength was affected by both the void content and the dispersion of the glass-fiber bundles. (C) 2000 Elsevier Science Ltd. All rights reserved.