In order to determine the influence of the different position of the cyano group in the dinitrile with benzothiazole ring upon the polymerization rate and the oxidative thermal stability of the polymers and to ascertain the excellent oxidative thermal stability of the polymers from the dinitrles with the benzothiazole ring

the dinitriles Ⅰ-Ⅲ with 5-cyano-benthiazole ring were synthesized by the following routes: The polymerization of these dinitriles was investigated．The polymerization rate of the dinitriles I and II was similar to that of their 6-eyano analogues IX and X．The infra-red spectrum of the polymers from I—III showed a s-triazine structure with the characteristic absorption at the region of 1510．1360 and 820 cm-1 and the disappearance of the nitrile absorption at ca．2230 cm-1．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 polymers from dinitriles IX and X．The results indicated that the weight losses were all low and similar of that of the polymers from IX and X．From the above results，we can conclude that the different position of the eyano group，whether at 5-or 6-position，has no influence upon the polymerization rate and the polymers from all these dinitriles with 5-or 6-cyano[Ienzothiazole ring possess excellent oxi-dative thermal stability．