Investigation on chain transfer reaction of benzene sulfonyl chloride in styrene radical polymerization

Abstract

The free radical polymerization of styrene was initiated with azobis(isobutyronitrile) in the presence of benzene sulfonyl chloride. Analysis of the terminal structures of the obtained polystyrene with 1 H NMR spectroscopy revealed the presence of a phenylsulfonyl group at the α-end and a chlorine atom at the ω-end of each polystyrene chain. The terminal chlorine atom in the polystyrene chains was further confirmed through atom transfer radical polymerization (ATRP) of styrene and methyl acrylate using the obtained polystyrenes as macroinitiators and CuCl/2,2'-bipyridine as the catalyst system. GPC traces of the products obtained in ATRP at different reaction times were clearly shifted to higher molecular weight direction, indicating that nearly all the macroinitiator chains initiated ATRP of the second monomers. In addition, the number-average molecular weights of the polystyrenes increased directly proportional to the monomer conversions, and agreed well with the theoretical ones.

Controlled synthesis of branched polystyrene via free radical polymerization of novel chain transfer monomer

“…The chain transfer constants (C tr ) of benzene sulfonyl chloride reported by our group 33 and Matsuda 34 using Mayo equation are 0.451 and 0.443, respectively, which are rather close to unity.…”

“…It was remarkable that with the increase of VBSC in the feed, the peak intensity of (a) increased, indicating that more VBSC units were incorporated into poystyrene chains. The signals of the end-standing methine proton next to the chloride atom due to the polystyrene radical abstracted a chloride from the sulfonyl chloride group were detected at 4.28-4.56 ppm (c), 33 which correspond to the structure of 2 and 3 in Scheme I. The signals at 6.30-7.20 ppm (d) were ascribed to the five aromatic protons of styrene unit and the signals at 1.29-2.40 ppm (e) were attributed to the backbone protons (-CH 2 -CH-) of both polystyrene and poly (VBSC) segment.…”

“…The signals due to the methylene protons (b) of the styrene unit bound to the sulfonyl group were detected at 3.09-3.30 ppm. 33 The signals at 7.28-7.70 ppm were ascribed to the four aromatic protons (a) of VBSC unit. It was remarkable that with the increase of VBSC in the feed, the peak intensity of (a) increased, indicating that more VBSC units were incorporated into poystyrene chains.…”

“…In our earlier work, 33 we have showed that a small amount of benzene sulfonyl chloride could effectively reduced M n of the obtained polystyrene and have proved the incorporation of phenylsulfonyl group (C 6 H 5 SO 2 -) and chloride atom at each end of polystyrene chain by 1 H NMR spectroscopy and ATRP technique. The chain transfer constants (C tr ) of benzene sulfonyl chloride reported by our group 33 and Matsuda 34 using Mayo equation are 0.451 and 0.443, respectively, which are rather close to unity.…”

Polystyrene-Based Hydroxide-Ion-Conducting Ionomer: Binder Characteristics and Performance in Anion-Exchange Membrane Fuel Cells

“…Styrene was subjected to free radical polymerization using benzenesulfonyl chloride as a chain transfer reagent and AIBN as an initiator [ 31 ]. Prior to polymerization, styrene was passed through a basic alumina column to remove the polymerization inhibitor.…”