“…In the past 40 years, phthalonitrile resins have been widely studied due to their high glass transition temperature (T g ), excellent thermal and thermo-oxidative stability, excellent mechanical properties, good moisture resistance, and excellent fire resistance. [1][2][3][4][5][6][7][8] Concurrently, to expand the application prospects of phthalonitrile resin in the marine, aerospace, and microelectronics industries, new types containing imide, 9 bismaleimide, 10 benzoxazine, 11 novoazole, 12 alkyl, 13 amino, 14 and other functional phthalonitrile monomers have been designed and successfully prepared. However, phthalonitrile resin usually contains biphenyl, 15,16 naphthyl, 17,18 pyridyl, 19,20 and other rigid groups.…”