Phenylethynyl terminated polyimide resin/carbon fiber composite catalytic cured at 300 °C and its performance

Phenylethynyl-terminated polyimide resin/carbon fiber composites become ideal structure materials for aerospace vehicle because of excellent mechanical properties and high-temperature thermal stability. However, the curing temperature of the polyimide resin/carbon fiber composite was higher than 370 °C, which caused much thermal stress that would inevitably deteriorate the performance of the composite and restrict its application. In this paper, a compound catalyst of isopropyl peroxide and cobalt naphthenate was used to catalyze the cross-linking reaction of phenylethynyl-terminated polyimide resin and decrease the curing temperature of the polyimide/carbon fiber composite. The result showed that the phenylethynyl characteristic absorption peak at cm⁻¹ was still existed in the polyimide resin without catalyst and disappeared for the catalystic polyimide resin when curing temperature was 300 °C, in which the spectrum was the same as that of the polyimide resin cured at 370 °C without catalyst. The inter-laminar shear strength and flexure strength of the catalytic polyimide/carbon fiber composite were 96.8 MPa and 2080.0 MPa, there were increases of 28.8% and 23.8% compared to that of the composite without catalyst cured 370 °C. All these results demonstrate that the compound catalyst of radical initiator and coordination catalyst could efficiently decrease the curing temperature of phenylethynyl terminated polyimide resin and increase the mechanical properties of the polyimide resin/carbon fiber composite.