Synthesis And Characterization Of Helical "Rod-Coil" Block Copolymers And Preparation Cyclic Polymers

In this work,a bifunctional initiator(PBB-Pd(II))containing propargyl bromoisobutyrate and alkyne-Pd(II)was designed and synthesized.The propargyl bromoisobutyrate unit of PBB-Pd(II)can initiate the atom transfer radical polymerization(ATRP)of vinyl monomers,while the Pd(II)complex could initiate the polymerization of phenyl isocyanides.Both the ATRP and Pd(II)-mediated isocyanide polymerization proceeded in living/controlled manner.Thus,combining the two living polymerizations,a series of well-defined block copolymers bearing rod poly(phenyl isocyanide)s and coil poly(acrylate)s segments could be facilely prepared in high yield with tunable composition,controlled molecular weights(Mns)and narrow molecular weight distributions(M_w/M_ns).What's more,benefiting from this synthetic strategy,well-defined core cross-linked star polymers were readily synthesized.Optically active block copolymers and star polymers could be facilely obtained by using chiral isocyanide monomers due to the formation of predominated one-handed helix.The chiral star polymers showed excellent enantioselective recognition ability in enantioselective crystallization of racemic compounds.Besides,by using a cyclic Ru catalyst,norbornenes were polymerized to create macro cyclic polymers.The rings could be easily synthesized with low molecule weight dispersity.What's more,the polymer possessed high molecule weight and the main chain presented a“endless-ring”structure.The catalyst was synthesis through modification of Grubbs catalyst G1.The NHC was linked to Ru via ligand exchange reaction,then inter-molecule reaction proceeded to afford cyclic reaction.Also,the norbornene monomer was modified with pentafluorophenol,the afforded ring polymers were allowed to be functionalized at side chains.