A high-temperature resistant phthalonitrile resin R802 for RTM process was introduced in this paper. Its
viscosity dependence on temperatures and time, DSC data under different heating rates, flexural strength, shearing
strength and interface between the fiber and resin are investigated. According to the viscosity-to-times results,sufficient
processing time is possible become there is a low viscosity platform longer than 180 minutes at 140℃. DSC results indicated
the resin began to gel at 180℃,to cure at 203℃ and to handle for better properties at 256℃. From the mechanical
properties results, there was an obvious advancement of about 3.8% higher of R802/ MT300 flexural strength tested at
200℃ and 18% higher of shearing properties tested at 300℃ compared to the results at room temperature. The flexural
properties could maintain 41.1% and strength retention of shearing properties is up to 44% at 500℃. There is an excellent
interface between fiber and resin of R802/ MT300 composites.