Atom transfer radical polymerization and copolymerization of vinyl acetate catalyzed by copper halide/terpyridine

Abstract

in Wiley InterScience (www.interscience.wiley.com).Copper-mediated atom transfer radical polymerization (ATRP) is versatile for living polymerizations of a wide range of monomers, but ATRP of vinyl acetate (VAc) remains challenging due to the low homolytic cleavage activity of the carbon-halide bond of the dormant poly(vinyl acetate) (PVAc) chains and the high reactivity of growing PVAc radicals. Therefore, all the reported highly active copper-based catalysts are inactive in ATRP of VAc. Herein, we report the first copper-catalyst mediated ATRP of VAc using CuBr/2,2 0 :6 0 ,2 00 -terpyridine (tPy) or CuCl/tPy as catalysts. The polymerization was a first order reaction with respect to the monomer concentration. The molecular weights of the resulting PVAc linearly increased with the VAc conversion. The living character was further proven by self-chain extension of PVAc. Using polystyrene (PS) as a macroinitiator, a well-defined diblock copolymer PS-b-PVAc was prepared. Hydrolysis of the PS-b-PVAc produced a PS-b-poly(vinyl alcohol) amphiphilic diblock copolymer.

Synthesis of poly(vinyl pivalate) by atom transfer radical polymerization in supercritical carbon dioxide

“…The PVA spectrum (Fig. 11) shows a broad peak of hydroxyl (-OH) groups at about 3300 cm À1 [46]. The absence of the carbonyl peak, C-O peak in the ester group and the tert-butyl peak in the PVA spectrum after saponification indicates that the PVPi was almost completely converted to PVA.…”

“…The signal (b) at 2.1 ppm corresponded to the methylene protons of the monomer unit [25]. The resonance (a) at approximately 5.85 ppm attributed to the methine proton adjacent to terminal bromine at the x-end, which indicates the preservation of end group [46].…”

“…The peaks at 4.75 (c) and at 1.7 ppm (e) were assigned to the methine (>CH-) and the methylene (-CH 2 -) protons of the VPi repeating units in the backbone of the polymer, respectively [6]. The peak (f) at 4.05 ppm was assigned to the methylene protons of the ethyl ester derived from the initiator EBiB [45,46]. The small peak (g) at 0.8 ppm was attributed to the methyl protons of the initiator.…”

“…The peak (c) at 1.0-1.2 ppm was attributed to the methyl (-CH 3 ) protons of the polymer. The peak (c) at about 1.20 ppm and peak (d) at 2.0 ppm were assigned to the methyl (-CH 3 ) protons of the PVPi and PVAc, respectively [46].…”

Uniform polymer–protein conjugate by aqueous AGET ATRP using protein as a macroinitiator

“…The effectiveness of ATRP in preparing uniform polymers has been demonstrated in the synthesis of polystyrene [15], polymethacrylates [16], polyacrylonitrile [17] and polyvinylacetate [18]. Heredia and Maynard [9] carried out aqueous ATRP under an N 2 atmosphere using bovine serum albumin and mutated lysozyme as the macroinitiator.…”