No abstract

Under 23 W CFL irradiation, block copolymers are obtained starting from a Pn-I macroinitiator in the presence of a benzaldehydic molecule-based catalytic system.

With fac‐Ir(ppy)3 as photoredox catalyst and ethyl 2‐bromoisobutyrate (EBiB) as initiator, the homopolymerization of methyl methacrylate (MMA) in different solvents, such as N,N‐dimethylformamide (DMF), acetonitrile, and anisole are run under irradiation of an LED lamp. The results show that anisole is a better solvent for the polymerization with regard to the polydispersity index (PDI). A well‐controlled polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) is demonstrated and the clean block copolymer of PMMA‐b‐PPEGMA is prepared with PDI less than 1.3; however, the 2‐(dimethylamino) ethyl methacrylate (DMAEMA) polymerization is poorly controlled. With the PMMA as macromolecular initiator, the block copolymer PMMA‐b‐PDMAEMA can be prepared with PDI around 2.0.

The benzaldehyde derivatives, such as 2,4‐dimethoxy benzaldehyde (PC1) and p‐anisaldehyde (PC2), were successfully used as photoredox catalysts (PCs) in combination with typical RAFT agent 4‐cyano‐4‐(phenylcarbonothioylthio)pentanoic acid (CTP) for the controlled photoinduced electron transfer RAFT polymerization (PET‐RAFT) of methyl methacrylate (MMA) and benzyl methacrylate (BnMA) at room temperature. The kinetics of the polymerizations showed first order with respect to monomer conversions. Besides, the average number molecular weights (Mn) of the produced polymers increased linearly with the monomer conversions and kept relatively narrow polydispersity (PDI = Mw/Mn). For example, the Mn of PMMA increased from about 3400 to 17,300 g mol−1 with the increasing in monomer conversion from 11% to 85%, and the PDI maintained around 1.36. The living features of polymerizations with the PC1 and PC2 as catalysts have also been further supported by chain extension and synthesis of PMMA‐b‐PBnMA diblock copolymer. As a result, the simplicity and efficiency of benzaldehyde derivatives catalyzed PET‐RAFT polymerization have been demonstrated under mild conditions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 229–236

A new strategy is developed to prepare both a,xdithiol and a,x-divinyl linear telechelic polythiolether oligomers by visible light induced thiol-ene chemistry in the presence of a fac-Ir(ppy) 3 photoredox catalyst. Polythiolether oligomers of well-defined end groups and controlled molecular weights have been successfully synthesized at varying monomer molar ratios of 1,4-benzenedimethanethiol (BDMT) to diethylene glycol divinyl ether (DEGVE).