Novel phthalonitrile-terminated polyarylene ether nitrile with high glass transition temperature and enhanced thermal stability

A series of polyarylene ether nitrile terminated with phthalonitrile (PEN-t-Ph) with different molecular weights have been prepared by adjusting the stoichiometric ratio of reaction. This novel PEN-t-Ph integrated the advantages of thermoplastic PEN resin and thermosetting phthalonitrile-based resin due to the crosslinking reaction of phthalonitrile (Ph) on the end of PEN-t-Ph chain. Therefore, PEN-t-Ph polymer can be fabricated using thermoplastic processing while being used in thermosetting fields. Thermal studies exhibited that the glass-transition temperatures of the various PEN-t-Ph crosslinked films were all above 209 °C, and were independent of the molecular weights of PEN-t-Ph. Besides, all the PEN-t-Ph crosslinked films possessed excellent thermostability with the 5 wt% weight loss temperatures all exceeding 518 °C. Dielectric measurement showed that the PEN-t-Ph with number-average molecular weight of 34,128 g mol−1 presented the highest dielectric constant and lowest dielectric loss, paving the way for its application in electronic materials.