Application ofS-alkylsulfonium salts of aromatic sulfides as new thermal latent cationic initiators

Abstract

The cationic initiation activity of derivatives of S‐methylsulfonium salts of dibenzothiophene (3a), diphenyl sulfide (4a), thioanisole (4d), and tetrahydrothiophene (5) was evaluated in the polymerization of glycidyl phenyl ether (1). These initiators were soluble in 1 and capable of initiating the cationic polymerization of 1 on heating, with the exception of methyltetrahydrothiophenium tetrafluoroborate (5; in the range of room temperature to 160 °C). Among them, methyldiphenylsulfonium tetrafluoroborate (4a) showed a moderate thermal latency that brought about the polymerization of 1 efficiently at 160 °C but not below 80 °C. S‐Alkylsulfonium salts of aromatic sulfides such as phenoxathiin (6a) and thianthrene (6b) also were evaluated for their activity in the cationic polymerization of 1, from which the thermal latent behavior of these salts also was confirmed (i.e., there was no reaction at 60 °C for 3 h, but there was a high enough conversion at 140 °C). Furthermore, the catalytic activity of S‐alkylsulfonium derivatives was controllable by both the property of the substituents on the aromatic rings and the character of the alkyl groups on the sulfur atom. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 18–27, 2000

Polymers and Sulfur: what are Organic Polysulfides Good For? Preparative Strategies and Biological Applications

“…More‐than‐four‐membered sulfide‐containing rings do not show any significant ring‐opening polymerisation activity either via anionic70 or cationic mechanisms, while the corresponding cyclic ethers (e.g., tetrahydrofuran) can be polymerised through a cationic mechanism. It is noteworthy that the stability of sulfonium ions in large rings has been usefully employed in the cationic ring‐opening of the ethers, for which either cyclic sulfonium ions can be used as cationic initiators,71 acting as an alkylating agent (Scheme ), or cyclic thioethers can be been used as chain terminators72 (Scheme ).…”

Imidazoles-Intercalated α-Zirconium Phosphate as Latent Thermal Initiators in the Reaction of Glycidyl Phenyl Ether (GPE) and Hexahydro-4-Methylphthalic Anhydride (MHHPA)

“…These catalysts can initiate polymerization under external impetus such as thermal or photo irradiation. Various kinds of latent catalysts are used in the polymerization reaction such as sulfonium salt [1][2][3][4], phosphonium salt [5], pyrazinium salt [6], N-heterocyclic carbene [7], aminimide [8], and sulfonate [9]. We have previously reported that primary alkylamines intercalated with α-zirconium phosphate (α-ZrP) can serve as latent thermal initiators in the reaction of glycidyl phenyl ether (GPE) [10] and that intercalation compounds of 1,4-diazabicyclo(2,2,2)octane (DABCO) and 1,8-diazabicyclo(5,4,0)undec-7-ene (DBU) with α-ZrP: α-ZrP·DABCO and α-ZrP·DBU show good performance as latent thermal catalysts in the reaction of GPE with hexahydro-4-methylphthalic anhydride (MHHPA) [11].…”

Control of reactions and network structures of epoxy thermosets

“…They demonstrated that several sulfonium [328][329][330][331][332][333][334][335][336], phosphonium [67,68,[337][338][339][340], pyridinium [296,298,[341][342][343][344] and other N-containing onium salts [345][346][347] could serve as latent thermal cationic initiators for epoxy polymerization. They observed that their initiating activity could be efficiently controlled through the variation of the electronic and steric properties of their substituents.…”