The influence of stamping temperature on the properties of a glass mat thermoplastic composite

The effect of varying the mold temperature on the mechanical properties of a stampable thermoplastic composite has been examined. A series of tensile, flexure and impact tests have shown that a distinct mold temperature dependency exists. This is most evident under impact loading conditions where it has been shown that the energy absorbing capacity of a material stamped at a low temperature is almost twenty-five percent lower than that of a similar composite molded at a much higher temperature. It is concluded that residual stresses resulting from the higher cooling rate may be in part responsible for this significant difference in impact resistance. It is also possible that greater damage occurred during the flow process in the lower temperature mold. A subsequent heat treatment cycle designed to simulate the passage of a component through a paint oven has been shown to improve quite significantly the energy absorbing capability of the material.