A new strategy is developed to prepare both α,ω-dithiol and α,ω-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). ¹H NMR and MALDI-TOF MS analyses demonstrate that as-prepared polythiolethers possess high end-group fidelity, which is further supported by the successful polyaddition of polythiolethers bearing α,ω-dithiol and α,ω-divinyl groups. For example, with the α,ω-dithiol- (M_n = 1900 g mol⁻¹, PDI = 1.25) and α,ω-divinyl-terminated (M_n = 2000 g mol⁻¹, PDI = 1.29) polythiolethers as macromonomers, the molecular weight of resulting polythiolether is up to 7700 g mol⁻¹ with PDI as 1.67. The reactivity of the terminal thiol group is further confirmed by the addition reaction with N-(1-pyrenyl)maleimide. UV-vis spectra and fluorescene measurements suggest that fac-Ir(ppy)₃ undergo a redox quenching process reacted with BDMT to generate thiyl free radicals. With these results, the mechanism of the thiol-ene reaction catalyzed by photoredox catalyst is proposed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 740–749

A new polymer chain growth mode, having multiple potential chain propagation sites, initiated by oligomer of α-methylstyrene (AMS) and styrene (St) (PAS) is presented in this article. The effects of PAS content, AMS fraction in PAS and reaction temperature on bulk polymerization of St have been investigated. It is demonstrated that the PAS performed as macroinitiator in the polymerization of St. The average molecular weights of products increase significantly with the evolution of the polymerization, which is different from conventional free radical polymerization. With 20 wt % macroinitiator, the molecular weights increase from 1.21 × 10⁵ to 3.00 × 10⁵ with the monomer conversion increasing from 15.3 to 83.0%. This unique feature is tentatively attributed to both the reversible polymerization–depolymerization of AMS segments at high temperature which could generate more than one propagation sites in a polymer chain and the combination termination of St free radical polymerization. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41460.

Flexible layer–layer poly(ethylene phthalate) (PET)/BaTiO₃ composite films with enhanced dielectric permittivity were fabricated by spin coating method, consisting of PET substrate film layer and modified BaTiO₃/acrylic resin hybrid coating layer. The thickness of coating layer was less than 3 μm (about 2% of PET film thickness), and therefore, the PET/barium titanate (BT) composite films remained flexible even at high volume fraction of BaTiO₃ fillers. The volume contents of BaTiO₃ were varied from 0 to 80%, and the solid contents of BaTiO₃/acrylic resin were in the range of 51.8–72.9%. Scanning electron microscopy showed strong interaction of finely dispersed BaTiO₃ particles with acrylic resin. Morphological profile also displayed uniform coating layer of modified BaTiO₃/acrylic resin and its strong adhesion with PET film. The dielectric constant of the PET/BaTiO₃ composite films increased by about 26% at 60 vol % BaTiO₃ loading when compared with the pristine PET film, whereas the dielectric loss decreased slightly. In addition, PET-grafted poly(hydroxylethyl methacrylate) brushes were used as substrate to introduce covalent bonding with the coating layer. Further enhancement of dielectric constant and reduction of dielectric loss were realized when compared with the composite films with bare PET substrate. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42508.

A new visible light-induced controlled radical polymerization of methacrylate with perfluoro-1-iodohexane (CF₃(CF₂)₅I) as the initiator in the presence of a photoredox catalyst (fac-[Ir(ppy)₃]) was developed. Mechanistically, a photoexcited fac-[Ir(ppy)₃]* complex reacted with dormant C-I species to generate the chain propagating radical and Ir^IVI complex, which could be reversibly reduced by the propagating radical. The molecular weight (M_n) and the corresponding distribution index (M_w/M_n = 1.4) were controlled in the polymerization of methyl methacrylate (MMA). For the polymerization of functional monomers, such as glycidyl methacrylate (GMA) and trifluoroethyl methacrylate, their monomer conversions could be up to 96 and 94%, respectively. No polymerization reaction took place without external light stimulation, indicating that the system was an ideal photo “on−off” switchable system. Furthermore, a clean diblock copolymer PMMA-b-PGMA was successfully synthesized with PMMA-I as the macroinitiator. With CF₃(CF₂)₅I as the initiator, short CF₃(CF₂)₅− group tags were introduced on the produced polymer chains. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3283–3291

The styrene (St) and isobornyl methacrylate (IBMA) random copolymer beads with controlled glass transition temperature (T_g), in the range of 105–158°C, were successfully prepared by suspension polymerization. The influence of the ratios of IBMA in monomer feeds on the copolymerization yields, the molecular weights and molecular weight distributions of the produced copolymers, the copolymer compositions and the T_gs of these copolymers was investigated systematically. The monomer reactivity ratios were r₁ (St) = 0.57 and r₂ (IBMA) = 0.20 with benzyl peroxide as initiator at 90°C, respectively. As the mass fraction of IBMA in monomer feeds was about 40 wt %, it was observed that the monomer conversion could be up to 90 wt %. The fractions of IBMA unit in copolymers were in the range of 35–40 wt % and T_gs of the corresponding copolymers were in the range of 119.6–128°C while the monomer conversion increased from 0 to greater than 90 wt %. In addition, the effects of other factors, such as the dispersants, polymerization time and the initiator concentration on the copolymerization were also discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

A new kind of conductive copolymers of aniline with phenol was designed and synthesized by using oxidation polymerization and the results showed that the apparent inherent conductivities of the copolymers are in the range of 10⁻² to 10⁻¹⁰ S/cm which covers from conductors to insulators. The results showed that the conductivity of the copolymers strongly depends on synthesis conditions, such as reaction time, molar ratios of oxidizer to monomers and aniline to phenol, concentrations of reactants, and reaction temperature. Compared to the conventional (co)polymers of aniline and its derivatives, the magnitudes of the reversible conductivity changes are very significant, about two orders, and get to the maximum readings in about 5 min when they are exposed to ammonia gas, hydrochloric acid gas, and a various vapors of organic compounds, such as methanol, alcohol, acetone, benzene, toluene, chloroform, carbon tetrachloride, etc. It should be noted that with the introduction of the weak acidic structural units into the polyaniline chains, the copolymers are reversibly responded to both acidic and basic gases promptly. Copyright © 2009 John Wiley & Sons, Ltd.

A universal photoassisted pathway to functionalize polymeric surfaces is presented by transferring the inert surface sp³ CH bonds into reactive groups, such as SO₃H, NH₂, SH, and COOH. The proposed method uses acetone as photoinitiator and different phenols with a para substituent XR as the reactants. Acetone excited by UV irradiation acts as a pair of scissors cutting both the surface CH bonds of the polymer substrate and the OH bonds of phenol, leading to the formation of carbon-centered surface chain free radicals and oxygen-centered phenoxy free radicals. By coupling of these two radicals, a variety of functional X groups with an R spacer from XR species of different phenol reactants were readily bonded to the polymeric surfaces, where phenol reactants included 4-hydroxylbenzene sulfonic acid for SO₃H, p-aminophenol and tyramine for NH₂, 4-hydroxythiophenol for SH, and tyrosine for COOH. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011