Allyl sulfonium salt as a novel initiator for active cationic polymerization of epoxide by shooting with radicals species

Abstract

A rapid cationic polymerization of cyclohexene oxide that completed within a few minutes was achieved by a new initiation system that involves (1) a copper-catalyzed reduction of benzoyl peroxide by an ascorbic acid derivative that generates free radicals and (2) capture of the radicals by allyl sulfonium salt having hexafluoroantimonate (SbF À 6 ) as a counter anion, followed by fragmentation of sulfonium radical cation, from which a super acid HSbF 6 was produced to initiate the rapid polymerization. The key factor in designing an efficient allyl sulfonium salt was attachment of an electron withdrawing ester group at the allyl group, of which ability to stabilize the formed radical can enhance the efficiency in trapping radicals by the allylic salt. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4178][4179][4180][4181][4182][4183] 2010

Redox two-component initiated free radical and cationic polymerizations: Concepts, reactions and applications

“…Therefore, the performances remained limited. Another study by Yilmaz et al pro posed a Cu/VitC/BPO radical initiating system that can lead to cations using a newly synthesized sulfonium salt [186]; it is a promising introduction to new categories of RCP initiating systems.…”

Expanding the Chemistry of the Class C Radical SAM Methyltransferase NosN by Using an Allyl Analogue of SAM

“…In the absence of methyl acceptor, the dAdo radical adds to the allyl moiety of the second allyl-SAM to produce sulfonium radical 14,w hich, upon one-electron oxidation, possibly by the oxidized Fe 4 S 4 cluster ( Figure 3C,p ath a), is converted into 15.S ince the major product in this reaction is 16,t he majority of 14 likely subjected to aC ÀSb ond fragmentation ( Figure 3C,p ath b);s imilar chemistry for sulfonium radicals has been reported in radical-promoted cationic polymerization reactions. [15] Theconformational change resulting from binding of the methyl acceptor substrate (e.g.M IA-Pan) to the enzyme facilitates the conversion of allyl-SAM into ATA, and the dAdo radical is then captured by the latter to produce 11,l eading to the production of 12 and 13 ( Figure 3B). Consistent with this proposal, adetailed time-course analysis showed that the yield of ATAishigher in the assay with MIA-Pan than that without MIA-Pan ( Figure S9).…”

Redox cationic frontal polymerization: a new strategy towards fast and efficient curing of defect-free fiber reinforced polymer composites

“…39,40 Yilmaz et al reported RCP formulation involving BPO, sulfonium salt and ascorbic acid reducing agent for ambient temperature curing of cyclic ether monomer. 41 However, this copper catalysed route to curing does not fall in the category of frontal polymerization. For the rst time, we introduce the idea of a redox cationic frontal polymerization (RCFP) for rapid and effective curing of epoxy monomers and demonstrate its applicability in curing technically relevant epoxy-based resins.…”