| New synthetic techniques have being developed to meet the needs in polymer and material science.Among them,the development of polymers with novel architectures and distinguishable properties are of considerable interest.In particular, nonlinear bock copolymers demonstrate unique structures and extensive properties, showing potential applications in physical and biological fields.With regards of their synthesis,the combination of living/controlled radical polymerization and ordinary organic reaction is of great benefit for the synthesis of nonlinear block copolymers and their preparation of advanced materials.Based on these types of polymerization techniques,in this dissertation we outlined our work in several parts.Using living radical polymerization and hyperbranched polymerization,we synthesized a number of nonlinear block copolymers,including H-shaped block copolymers, linear-hyperbranched block copolymers,hyperbranched-contained 3-miktoarm star polymers.The self-assembly behavior of H-shaped block copolymers and their composites with carbon nanotubes were also investigated.Based on the researches of the precursors,the dissertation described several outspread works in the synthesis of topologically structured polymers and preparation of polymer nanomaterials in this dissertation.The main outline is listed as follows:1) A series of hydrophilic H-shaped block copolymers with well-defined structures and low polydispersity were prepared via ATRP of TMSPMA with PEG as macroinitiator.Multiple vesicular morphologies are obtained via self-assembling these H-shaped block copolymers in water,which can be modified by tone of the chain length ratio.After polycondensation reaction among hydrophobic chains,PTMSPMA,these hollow structures are fixed and transformed into organic-inorganic hybrid materials. 2) A simple and unique strategy has been developed for dispersion of multiwalled carbon nanotubes(MWCNTs) in various solvents including water and organic solvents,and this can be achieved by encapsulating MWCNTs into large-compound vesicles(LCVs) formed from self-assembly of H-shaped block copolymers.This unique non-covalent approach is nondestructive,and the original structure of MWCNTs remains in the resultant MWCNTs/LCVs nanocomposites.And polymers around the CNTs self-assembled into aggregates with different morphologies.The resultant nanocomposites have combined the properties of CNTs and polymer vesicles, which have potential application in drug control release and material reinforcement.3) Linear-hyperbranched block copolymers were prepared by combination of ROP and SCVP with a dual-initiator.During polymerization,inimer can self-initiate to form hyperbranced byproduct,which can be easily eliminated by precipitation in methanol.The obtained block copolymers showed a lower polydispersity,and the two block lengths can be tuned by monomers/initiator feed ratio.4) 3-Miktoarm star terpolymers with hyperbranched fraction were prepared by the combination of the SCVP and ROP.First,we synthesized the marco chain transfer agent,PEG terminated with hydroxyl and trithiocarbonate groups. After polymerization of monomer CL and inimer BBEA,miktoarm star terpolymers were obtained and mixed with hyperbranched homopolymer, PBBEA as byproduct.After fractional precipitation in petroleum ether,the resultant 3-miktoarm star terpolymers with well-defined structure and low polydispersity were obtained.5).Star polymers terminated with maleimide groups were prepared via an arm-first approach.The synthetic procedure is as follows:First,we synthesized the ATRP initiator terminated with maleimide groups pre-protected by furan.The PS marcoinitiators were obtained after polymerization of styrene.And then,the star polymers were prepared by the polymerization of DVB on PS via an arm-first approach.After de-protection reaction via heating,the maleimide groups were exposed on the surface of star polymers.The resultant star polymers can be further functionalized by the reaction of the maleimide groups.
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