<i>N</i>‐alkoxy‐pyridinium and <i>N</i>‐alkoxy‐quinolinium salts as initiators for cationic photopolymerizations

Abstract

Abstract The polymerization of n ‐butyl vinyl ether (BVE), cyclohexene oxide (CHO) and 3,4‐epoxycyclohexyl(methyl)‐3′,4′‐epoxycyclohexane carboxylate (EEC) was initiated upon UV irradiation (λ inc &gt; 300 nm) of dichloromethane solutions containing N ‐ethoxy‐2‐methylpyridinium ( V ), N ‐ethoxy‐4‐phenyl‐pyridinium ( VI ) or N ‐ethoxy‐isoquinolinium hexafluorophosphate ( VII ). Whereas the bifunctional EEC was converted into an insoluble gel, BVE and CHO formed polymers of molar mass: M w = 2 X 10 4 −2 X 10 5 (PCHO) and M w ≈ 2 X 10 4 (PBVE). Protons are formed with a rather high quantum yield [ø(H+) = 0.48 on irradiating VII in dichloromethane; titration with sodium p ‐nitrophenolate] and it is, therefore, assumed that the polymerization is initiated by photochemically generated protons. © 1992 John Wiley &amp; Sons, Inc.