Yilmaz Gorkem, Iskin Birol, Yilmaz Faruk, Yagci Yusuf
Department of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey.
Department of Chemistry, Gebze Institute of Technology, 41400 Gebze, Kocaeli, Turkey.
ACS Macro Lett. 2012 Oct 16;1(10):1212-1215. doi: 10.1021/mz3004743. Epub 2012 Oct 2.
A novel visible light sensitive photoinitiator system for the cationic polymerization of typical monomers, for example, of oxiranes, such as cyclohexene oxide, vinyl ethers, such as iso-butyl vinyl ether, and other vinyl monomers, such as -vinylcarbazole, using fullerene derivatives is described. The cationic polymerization of these monomers was initiated at room temperature upon irradiation in the visible region (λ > 400 nm) in bulk or chlorobenzene solutions with polystyrene-C (PS-C) adduct or bare C, respectively, in the presence of oxidizing salts such as silver hexafluorophosphate (AgPF) and diphenyliodonium hexafluorophosphate (PhIPF). A feasible mechanism, as correlated with optical absorption measurements, free energy changes (Δ), and proton scavenging studies, involves formation of exciplex by the absorption of light in the first step. Subsequent electron transfer from excited C or PS-C to oxidizing salt yields radical cations of the fullerene derivatives. Both radical cations and a strong Brønsted acid derived by hydrogen abstraction initiate the cationic polymerization of a variety of monomers.
描述了一种新型的可见光敏感光引发剂体系，该体系用于典型单体（如环氧乙烷类，如氧化环己烯；乙烯基醚类，如异丁基乙烯基醚；以及其他乙烯基单体，如咔唑乙烯）的阳离子聚合反应，使用的是富勒烯衍生物。这些单体的阳离子聚合反应在室温下，于本体或氯苯溶液中，分别在聚苯乙烯-C（PS-C）加合物或裸碳存在下，在可见光区域（λ>400nm）照射时引发，同时存在诸如六氟磷酸银（AgPF）和六氟磷酸二苯基碘鎓（PhIPF）等氧化盐。与光吸收测量、自由能变化（Δ）和质子清除研究相关的一种可行机理，第一步涉及通过吸收光形成激基复合物。随后，从激发态的C或PS-C向氧化盐的电子转移产生富勒烯衍生物的自由基阳离子。自由基阳离子和通过氢提取产生的强布朗斯特酸都引发各种单体的阳离子聚合反应。
