In order to elucidate the relationship between the structure of the dinitriles and the polymerization rate and the oxidative thermal stability

the dinitriles with benzoxa-zole

benzoxazinone and phthalimide rings were synthesized by the following routes:polymerization rate of the dinitrile II with benzoxazole ring and IV with phthalimide ring was similar to that of the dinitrile I with benzothiazole ring at 300℃ and using 1.0％ of zinc chloride as the catalyst．The infra-red spectrum of the polymers from II and IV showed a S-triazine structure with the characteristic absorptions at 1506

1354，811cm-1 and 1510，1350，cm-1．respectively，and the disappearance of the nitrile absorption at ca．2230 cm-1．But the dinitrile III with benzoxazinone ring polymerized much slowly at the same conditions．The isothermal weight loss at 371℃ in air during 200 hours of the polymers from these dinitriles was measured and compared with that of the dinitrile I．The results indicated that the oxidative thermal stability of the polymers from the dinitriles II．IV was inferior to that Df the dinitrile I．