Preparation and thermal properties of novel phthalonitrile oligomer containing biphenyl ethernitrile/bisphthalonitrile blends

A kind of novel n = 2 phthalonitrile oligomer containing biphenyl ethernitrile (2PEN-BPh) had been firstly synthesized from 2,6-dichlorobenzonitrile, 4,4′-biphenol and 4-nitrophthalonitrile via solution reaction, and the 2PEN-BPh was characterized by FTIR, ¹H-NMR spectra which exhibited that cyano groups and ethernitrile linkages existed in the backbone of 2PEN-BPh. The 2PEN-BPh oligomer was blended with bisphthalonitrile monomer, the curing reaction behaviors of the blends were studied by FTIR, DSC, and rheological analysis. The thermal and thermo-oxidative stabilities of the 2PEN-BPh/BPh polymers were investigated by TGA, and the results showed that the completely cured polymers could achieve char yields up to 78% at 800°C in nitrogen, above 11% at 800°C in air. The whole research indicated that the 2PEN-BPh/BPh blends could efficiently improve the processability of BPh monomer without scarifying other desirable high temperature properties.