AZO-Containning polytetrahydrofuran (AZO-PTHF) was synthesized by the cationic ring-opening polymerization of THF

using 4

4'-azobisisocyanovaleryl chloride as initiator and antimony pentachloride as catalyst. The polymer could form macromolecular free radical and initiate some vinyl compounds polymerization by thermal decomposition of AZO group. The radical of PTHF was identified by means of ESR determination and the decomposition temperature was also obtained.