Processing and Properties of Carbon Fiber-reinforced PMR Type Polyimide Composites

Abstract

Carbon fiber-reinforced PMR-type polyimide composites were prepared from T-300 carbon fibers and polyimide matrix resin derived from 4,4′-methylenediamine (MDA), p-phenylenediamine ( p-PDA), diethyl ester of 3,3′,4,4′-oxydiphthalic acid (ODPE) and monoethyl ester of cis-5-norbornene-endo- 2,3-dicarboxylic acid (NE). The rheological properties of the PMR polyimide matrix resin were investigated. Based on this information, an optimized molding cycle was designed for fabricating T-300/PI composites. The composites exhibited high thermal stability and good mechanical properties. The glass transition temperature ( Tg) determined by dynamic mechanical analysis and the decomposition temperature at 5% of weight loss ( T5) were higher than 360 and 540°C, respectively. The flexural strength and shear strength of the composites were 1560 and 95 MPa, respectively. The composite also exhibited good thermal-oxidative stability and hygrothermal resistance as evaluated under the conditions of isothermal aginginairat320°C and hygrothermal aging at 120°C under 2 atm. The unaged thermal and mechanical properties of the composites were hardly changed after isothermal aging for 500 h and hygrothermal aging for 100 h. The scanning electron microscopic analyses for both the isothermally and hygrothermally aged composites revealed that the matrix was bonded to the fibers very well, implying that no interface degradation occurred during the aging experiments