Thermal-oxidative aging effects on the properties of a carbon fiber-reinforced phenylethynyl-terminated poly(etherimide)

This paper reports the results of an investigation of thermal-oxidative aging effects on the properties of a carbon fiber-reinforced high-performance phenylethynyl-terminated poly(etherimide). Composite panels and neat resin samples were aged at 204 °C in environments of four different oxygen partial pressures: 0, 2.84, 20.2, and 40.4 kPa. Aging times were 1750, 3500, and 5000 h. Despite the lack of visual evidence of degradation and minimal mass loss from both composite and neat-resin specimens following thermal-oxidative aging, transverse flexural strength decreased with increasing oxygen partial pressure and aging time. The retention of transverse flexural strength was described as a function of oxygen partial pressure and aging time; retention was proportional to (aging time)0.29. Profiles of Vickers Hardness across the cross sections of aged neat resin samples demonstrated deeper and more severe degradation with increased oxygen partial pressure. In addition to mechanical properties, the effects of thermal oxidative aging on static and dynamic thermomechanical properties were measured; 5000 h of aging resulted in a glass transition temperature increase. The size of this increase decreased with increasing oxygen partial pressure. These results, along with additional mechanical and thermomechanical property measurements are reported and discussed.