Novel high-temperature-resistant single-polymer composites based on self-reinforced phthalonitrile end-capped polyarylene ether nitrile

A series of phthalonitrile end-capped polyarylene ether nitrile (PEN-Ph) with different structures has been synthesized by adjusting the molar ratio of biphenyl (BP) to hydroquinone (HQ). Furthermore, based on the PEN-Ph, self-toughened and self-reinforced single-polymer composites were successfully prepared. The relationship between structure, morphology, and properties of the PEN-Ph system was also investigated in detail. From the polarizing micrographs, it is concluded that the sample-1# (molar ratio of BP to HQ is 10:93) possesses larger size spherocrystal. Moreover, the Tg decreases from 206.1 to 178.2 with the increasing HQ content. The mechanical measurement demonstrates that the sample-2# (molar ratio of BP to HQ is 20:83) shows the best tensile strength. Most importantly, the polarizing micrographs which illustrated the morphologies of PEN-Ph as a function of temperature, provide the direct evidence for the PEN-Ph crystals solidification by crosslinking reaction. Hence, taking the thermal and mechanical properties in consideration, the sample-2# will be a good candidate for the high-temperature-resistant single-polymer composites.