Study on the properties of high temperature resistant phthalonitrile oligomer containing biphenyl ethernitrile

In this paper, some phthalonitrile prepolymers containing biphenyl ethernitrile with different prepolymerization extent were synthesized. During this procedure, 2, 6-bis(4-diaminobenzoxy) benzonitrile(BDB) was used as curing agent and the effect of different reaction extent on the properties of 2PEN-BPh oligomer. The curing reaction behaviors of the oligomer and prepolymers were studied by DSC and rheological analysis. TGA was used to conduct the thermal stability of the cured 2PEN-BPh polymers. The results showed that prepolymerization for 2h was the optimal prepolymerization time when the concentration of curing agent was 3% by weight;and the 2PEN-BPh polymers processed good thermal and thermo-oxidative stabilities, fully cured 2PEN-BPh exhibited the initial decomposing temperature above 515℃, and the temperatures at weight loss 5% was exceeded 556℃, the char yields at 800℃ were above 78% in nitrogen and above 44% in air.