VARTM & RTM Processing of PBT & PA Thermoplastic Composites

Abstract : Vacuum assisted resin transfer molding (VARTM) and resin transfer molding (RTM) processes have been successfully developed to enable infusion of thermoplastic pre-polymers into glass and carbon fiber performs at temperatures up to 210 deg C. The pre-polymers used in this study were CBT (Cyclic Butylene Teraphthalate oligomer) leading to a PBT composite, APLC-12 (Anionically-Polymerised Lactam -12) leading to a PA-12 composite, and APLC-6 (Anionically-Polymerised Lactam -6) leading to a PA-6 composite. Mixtures of PA-12 and PA-6 were also examined. Traditionally it has not been easy to mold thermoplastic-reinforced composites due to their high viscosities. High temperatures and pressures were always required to fully impregnate fiber beds. Liquid composite molding processes, such as those demonstrated in this report, were virtually impossible. The employment of an activated pre-polymer melts eliminates the problems associated with high viscosity. All of the materials processed here were using vacuum pressure only.