Photosensitized cationic polymerization using allyl sulfonium salt

Abstract

The cationic polymerization of cyclic ethers such as cyclohexane oxide (CHO) and vinyl monomers such as butyl vinyl ether (BVE) and N-vinylcarbazole (NVC) is initiated upon irradiation at A 380 nm in CH,CI, solution containing an allylic sulfonium salt, namely, 2-ethoxycarbonyl-2-propenylthiophenium hexafluoroantimonate (1) (EMT'SbF;), and one of the following compounds: benzophenone, anthracene, thioxanthone, perylene or phenothiazine. Electron transfer and hydrogen abstraction mechanisms were proposed for the initiation step. Stable cation radicals of phenothiazine were also prepared, and the cationic polymerization of butyl vinyl ether was initiated by these cation radicals.

PolymericN-allyl vinylpyridinium salts as addition-fragmentation type initiators for cationic polymerization

“…Specially designed allylic salts such as thiophenium,8, 9 pyridinium,10 alkoxy pyridinium11–15 and phosphonium16 salts of the following structure, have been shown to participate in addition–fragmentation initiation. Such initiation occurs under free radical conditions whenever photochemically‐ or thermally‐generated radicals add onto the allylic salts bearing both activated unsaturation and a weak bond.…”

New Photochemical Processes for Macromolecular Syntheses

“…Such compounds include anthracene, pyrene, perylene, and thiophene derivatives [37,[50][51][52][53][54][55]. All mechanisms of cationic polymerizations are demonstrated below.…”

Photoinitiated Metal Free Living Radical and Cationic Polymerizations

“…Following the pioneering work of Crivello describing the use of onium salts as photoinitiators for cationic polymerization of oxiranes and vinyl ethers [39,40], there has been tremendous interest in the development of various photoinitiators [41][42][43][44][45]. Among them, iodonium and sulfonium salts are the most widely used photoinitiators due to their thermal stability, solubility in most of the cationically polymerizable monomers, and efficiency in generating reactive species upon photolysis [46][47][48].…”