Reversible addition-fragmentation chain transfer polymerization of vinyl chloride

Abstract

Controlled/"living" radical polymerization (CLRP) of vinyl chloride (VC) via the reversible addition-fragmentation chain transfer (RAFT) process is reported for the first time. The cyanomethyl methyl(phenyl) carbamodithioate (CMPCD) was found to be an efficient RAFT agent enabling the CLRP polymerization of VC monomer under certain experimental conditions. Two different radical initiators, having very distinct half-life times at room temperature, were employed in this study. The kinetic studies of RAFT polymerization of VC show a linear increase of the molecular weight with the monomer conversion and the lowest polydispersity (PDI) ever reported for poly(vinyl chloride) (PVC) synthesized with CLRP method (PDI ∼ 1.4). The resulting PVC was fully characterized using the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS),1H nuclear magnetic resonance spectroscopy (1H NMR), and gel permeation chromatography (GPC) techniques. The1H NMR and MALDI-TOF-MS analysis of PVC prepared via RAFT polymerization method have shown the absence of structural defects and the presence of chain-end functional groups. The "livingness" of the PVC was also confirmed by a successful reinitiation experiment. The suitability of the RAFT agent was also confirmed via high-level ab initio molecular orbital calculations.