Highly efficient and well‐controlled ambient temperature RAFT polymerization of glycidyl methacrylate under visible light radiation

Abstract

A range of well-defined poly(glycidyl methacrylate) (PGMA) polymers and their corresponding block copolymers were synthesized via 2-cyanoprop-2-yl(4-fluoro) dithiobenzoate or CPFDB-mediated ambient temperature reversible addition fragmentation chain transfer radical polymerization or RAFT polymerization under environmentally friendly visible light radiation (k ¼ 405-577 nm), using a (2,4,6-trimethylbenzoyl) diphenylphosphine oxide photoinitiator. As comparison, CPFDB-mediated ambient temperature RAFT polymerizations of glycidyl methacrylate (GMA) under both full-wave radiation (k ¼ 254-577 nm) and long-wave radiation (k ¼ 365-577 nm) were also studied in this article. The results indicated that CPFDB moieties were significantly photolyzed under either full-wave radiation or long-wave radiation, thus undermining the controlled behavior of these RAFT processes. Whereas this photolysis was significantly suppressed under visible light radiation, thus CPFDB functionalities exerted well control over RAFT process, leading to a remarkably living behavior up to 90% GMA monomer conversions. This strategy facilitates the facile synthesis of well-defined PGMA polymers. More importantly, under visible light radiation, a relatively high initial molar ratio of GMA to CPFDB and TPO led to shortening initialization period of RAFT process and accelerating overall polymerization rate. These effects are remarkably in favor of the facile synthesis of well-defined PGMA polymers and PGMA-based copolymers with high molecular weights. V V C 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5091-5102, 2007

Selective Controlled/Living Photoradical Polymerization of Glycidyl Methacrylate, Using a Nitroxide Mediator in the Presence of a Photosensitive Triarylsulfonium Salt

“…The signals at 2.3-1.4 ppm and 1.4-0.7 ppm were based on the methylene (a) and methyl protons (b) of the main chain. These assignments agreed with those for PGMA obtained by the RAFT and free radical polymerizations of the vinyl group [36,37]. The presence of the oxirane rings in the polymer structure and good agreement in the ratio of the respective signal intensity with the PGMA structure obtained by the polymerization of the vinyl group indicate that no occurrence of the cationic ring-opening polymerization of the oxirane rings.…”

Studies on Photoinduced ATRP in the Presence of Photoinitiator

“…[11][12][13][14][15] A thiocarbonylthio compound, known as a classical RAFT agent, is a photosensitive molecule that readily undergoes reversible b-cleavage at the carbon sulfur bond and thus yields some control over the radical polymerization process under UV irradiation. [16][17][18][19][20][21] Some studies have also focused on UV-induced ATRP and the effect of UV-Vis radiation on the controlled nature of the polymerization process. [22][23][24][25][26][27] Although some success was achieved by the above techniques, the conditions for true photoinduced controlled radical polymerization were not attained.…”

Photo-controlled/living radical polymerization mediated by 2,2,6,6-tetramethylpiperidine-1-oxyl in inert atmospheres

“…There have already been reported several photo-controlled/living radical polymerization systems. Examples include the photo-controlled radical polymerization using bisacrylphosphine oxide and bisacrylgermanium photoinitiators [21], photoiniferter polymerization [22][23][24][25][26], photoiniferter-combined RAFT [27,28], photo-induced ATRP [29], UV-induced ITP [30], and photo-NMP [31]. In particular, the photo-NMP using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as the mediator has been reported in recent years to produce polymers with the comparatively narrow molecular weight distributions of ca.…”