Synthesis of sulfur-containing alternating copolymers by RAFT copolymerization of phenyl vinyl sulfides

An electron-donating S-vinyl monomer, phenyl vinyl sulfide (PVS), was copolymerized with electron-accepting monomers, such as maleic anhydride (MA), N-methyl maleimide (MMI), and N-phenyl maleimide (PMI), via a reversible addition-fragmentation chain transfer (RAFT) process. Among various chain transfer agents (CTAs), the trithiocarbonate-type CTA was found to be effective in achieving controlled copolymerizations of PVS with the electron-accepting monomers with a strong alternating tendency. The controlled nature of the RAFT copolymerization of PVS with PMI was confirmed by the formation of narrow polydispersity products, with the molecular weight being controlled by the monomer/CTA molar ratio, resulting in an observed linear increase in the molecular weight with the polymer yield. RAFT copolymerization of PVS with an asymmetrical divinyl monomer, N-vinyl maleimide, in the presence of the trithiocarbonate-type CTA allowed the synthesis of alternating copolymer with pendant double bonds, which were available for subsequent thiol-ene click reaction to produce novel sulfur-containing copolymers.