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(η6‐ N ‐alkylcarbazole) (η5‐cyclopentadienyl) iron hexafluorophosphate salts in photoinitiated and thermal epoxy polymerization
Author(s) -
Wang Tao,
Li Zhiquan,
Zhang Ying,
Hassan Kafssi,
Wang Xiaoning
Publication year - 2009
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21329
Subject(s) - cationic polymerization , hexafluorophosphate , polymerization , ring opening polymerization , photopolymer , epoxy , materials science , polymer chemistry , monomer , photochemistry , chemistry , polymer , organic chemistry , composite material , ionic liquid , catalysis
(η6‐Carbazole)(η5‐cyclopentadienyl) iron hexafluorophosphate salts (CFS PF 6 ) are capable of photoinitiating cationic polymerization of epoxy monomers directly upon irradiation with long‐wavelength UV light. To improve the solubility of CFS ferrocenium salts in epoxides, two CFS photoinitiators have been prepared: [cyclopentadiene‐Fe‐ N ‐buylcarbazole] hexafluorophosphate (C4‐CFS PF 6 ) and [cyclopentadiene‐Fe‐ N ‐octylcarbazole] hexafluorophosphate (C8‐CFS PF 6 ), bearing C4 and C8 alkyl chains, respectively, on the nitrogen atom. Studies with real‐time infrared spectroscopy have shown that C4‐CFS and C8‐CFS photoinitiators exhibit high efficiency in polymerization of 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexane carboxylate (ERL‐4221) epoxy monomer, but lower efficiency in polymerization of di(2,3‐epoxypropyl)‐3,4‐epoxy‐1,2‐cyclohexanedioate (TDE‐85) epoxy monomer. Benzoyl peroxide (BPO) sensitizer was very effective in improving the photoinitiating activities of CFS in polymerization of both ERL‐4221 and TDE‐85. DSC studies have shown that C4‐CFS and C8‐CFS photoinitiators can also be employed as thermal initiators for the cationic ring‐opening polymerization of epoxides at moderate temperatures. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers