Synthetic Brush Type Multicomponent Copolymer By ATRP/RAFT Combined Technology

Brush-type polymer refers to the macromolecular with high-density grafting of polymeric segments on the polymer backbone.Brush-type polymers have broad application prospects in the fields such as drug delivery,catalysis,and biological materials,because of their special properties,such as low crystallinity,small hydrodynamic volume,and good solubility.Brush-type polymer has received extensive attention from researchers in recent years.In this study,a series of multi-component copolymers with brush structure were synthesized by controlled radical polymerization.?1?Using dodecyl trisulfide carbonate?DDMAT?as a chain transfer agent,p-chloromethylstyrene?VBC?and styrene?St?as monomers,diblock copolymer PVBC-b-PS with a narrow molecular weight distribution?PDI of1.54?was prepared through reversible addition fragmentation polymerization?RAFT?technique.Then benzyl chloride groups in the PVBC structure were used as initiators,two brush-type terpolymers PVBC-b-PS-g-PMMA?PDI=3.38,Mn=43,000,VBC repeat unit graft ratio was 12.2%?and PVBC-b-PS-g-PBMA?PDI=2.87,Mn=41000,VBC repeat unit graft ratio was 15.8%?synthesized by atom transfer radical polymerization?ATRP?from methacrylate?PMMA?and polybutyl methacrylate?PBMA?respectively.The polymerization products were characterized by ¹H NMR,GPC,DSC and IR techniques.?2?Using AIBN as initiator,DDMAT as chain transfer agent,VBC and St as monomers,binary random copolymers?PVBC-co-PS?with different monomer molar ratio n_VBC/n_St,1:3 and 3:1)was synthesized by RAFT.The block polymer was characterized by GPC,FT-IR,¹H NMR and other techniques.The molar ratios of repeat units measured by NMR datum were1:1.32 and 5:1.Subsequently,the benzyl chloride groups in the PVBC structural unit were used as the initiators,and the methyl methacrylate or butyl methacrylate as the monomer,and the two brush copolymers PVBC-co-PS-g-PMMA(VBC repeat unit graft ratio was 22.7%and 39.4%for n_VBC/n_St of 3:1and of 1:3,respectively)and PVBC-co-PS-g-PBMA(VBC repeat unit graft ratio was 38.3%and 48.2%for n_VBC/n _St of 3:1and of 1:3,respectively)were obtained by the ATRP technique.When the content of VBC unit in the main chain is reduced,the influence of steric hindrance to the grafting polymerization decreases,and the grafting rate of VBC unit in the main chain increases..?3?The two-block copolymers PBMA-b-PGMA and PBMA-b-PGMA were successfully prepared by RAFT method,using DDMAT as a chain transfer agent.