A Novel Initiation System for the Cationic Polymerization of Glycidyl Phenyl Ether:  Triphenylcyclopropenium Tetrakis(pentafluorophenyl)gallate/Cyclohexanone

Triphenylcyclopropenium hydroxytris(pentafluorophenyl)borate salt for solvent free epoxy curing

“…Irradiation of compound 3 at 300 nm resulted in formation of hexaphenylbenzene [17,20]. The 19 F NMR analysis before irradiation show characteristic 19 F NMR spectrum for HOB(C6F5)3 -.…”

“…Results showed that compounds 2 and 3 exhibit excellent activity as room temperature thermal initiators for epoxide polymerization. Initiator compound 3 exhibits excellent solubility in epoxy matrices and showed remarkable activity compared with compound 2 in the absence of GBL; compound 3 does not require cyclohexanone to produce the initiating species as in the case of [TPCP][Ga(C6F5)4] [17]. To overcome solubility restrictions, in general, solvents such as -butyrolactone are used.…”

“…[TPCP] [Ga(C6F5)4] requires cyclohexanone to form the actual initiating species [16]. In the presence of trace amounts of water, [TPCP] [Ga(C6F5)4] also acts as a photoinitiator in polymerization of glycidyl phenyl ether [17].…”

Substituted Cyclopropenium Salts as Photoinitiators for Cationic Polymerization of Glycidyl Phenyl Ether

“…We thought TPCP a potentially interesting cation with which a cascade of nonnucleophilic anions might be paired for investigation as photochemical superacid sources. We have recently reported that triphenylcylopropenium (TPCP) tetrakis(pentafluorophenyl)gallate is a good thermal initiator for the cationic polymerization of glycidyl phenyl ether (GPE) when used with cyclohexanone . Since it is poorly soluble in epoxy resins, this new initiator afforded limited photopolymerization of standard epoxy resins such as epoxy-functionalized silicones.…”

“…We have recently reported that triphenylcylopropenium (TPCP) tetrakis(pentafluorophenyl)gallate is a good thermal initiator for the cationic polymerization of glycidyl phenyl ether (GPE) when used with cyclohexanone. 9 Since it is poorly soluble in epoxy resins, this new initiator afforded limited photopolymerization of standard epoxy resins such as epoxy-functionalized silicones. However, TPCP tetrakis(pentafluorophenyl)gallate dissolves completely in glycidyl phenyl ether (GPE) and initiates its photopolymerization when irradiated at 300 nm.…”