PHOTOINITIATED CATIONIC POLYMERIZATION OF OXETANE FORMULATED WITH OXIRANE

Photoinitiated cationic polymerization of oxetane, oxirane (epoxide), and a formulation of both was carried out and their reactivity compare d. To investigate a formulated system of oxetane and oxirane in photoi nitiated cationic polymerization, computational and experimental metho ds were used. In the computational study, we employed a semiempirical molecular orbital method (AM1). On the other hand, the reactivities of each system were evaluated and compared experimentally by a real-time FT-IR method. The computational study reveals that oxetane seems to p olymerize in S(N)2 mechanism, but two possibilities, of S(N)1 mechanis m through the a-cleavage and of S(N)2 mechanism through beta-cleavage, are implied for oxirane. Using the real-time FT-IR method, the formul ation of oxetane and oxirane was proved to possess rather high reactiv ities of oxetane toward photoinitiated cationic polymerization. The fo rmulated system exhibited slightly lower number-average molecular weig ht than oxetane but higher than oxirane. These experimental observatio ns are well explained in terms of the calculated reaction paths. (C) 1 995 John Wiley and Sons, Inc.