1994 Volume 43 Issue 495 Pages 1532-1538
Pitch-based carbon short fibers (PCF) treated with five kinds of coupling agents(CA), were added by 22.2wt% to fill three kinds of multi-functional epoxy resins cured with three kinds of acid anhydrides as hardener. Several mechanical properties of the composite materials were studied by using a Rheovibron in the temperature range from -150 to 300°C, and by using an Instron tester. The glass transition temperature(Tg) of the composites filled with CA-treated PCF (CA) was higher than that of the composites filled with untreated PCF (UT). The storage modulus (E')of the composites filled with CA-treated PCF increased also in a wide temperature range, including the glassy region at low temperature (-140°C) and room temperature (25°C), up to high temperature (200°C). However, the increase in both Tg and E' depended on the combination of epoxy resin and hardener. The values of E' of the composites at 25°C were larger than those estimated from the rule of mixture or Halpin-Tsai equation modified by Nielsen et al.. It was also found that the effect of CA-treatment on the flexural strength of composite materials was small. In the case that the matrix of composites became brittle, the effect of CA-treatment on the flexural strength appeared remarkably large. Consequently, the multi-functional epoxy resins can be made a composite material having higher heat resistant and higher modulus by filling it with CA-treated PCF.