Preparation Of Functionalized Copolymers By RAFT Polymerization And Investigation Of Their Properties

“Living”/controlled radical polymerization （LRP） techniques have manyadvantages, which have attracted many attentions from polymer chemists. At present,nitroxide-mediated polymerization （NMP）, reversible addition-fragmentation chaintransfer （RAFT） polymerization, atom transfer radical polymerization （ATRP） andsingle electron-transfer living radical polymerization （SET-LRP） have been developedas the important techniques in LRP field. For different LRP techniques, the way toachieve the “living”/controlled polymerization is the same, that is establishing anequilibrium between the active species and the dormant species. Through LRPtechnique, block copolymers, graft polymers, star polymers and other polymers withcomplicated structures were prepared. LRP techniques have became one of the mostimportant polymer synthesis method now a days. In this thesis, the content of the workconsisted of the two parts：（1） Grafting copolymers with PNIPAM backbone and PVAc or PNVP side chainswere synthesized. We were inspired to convert the secondary amide moieties ofPNIPAM backbone into dithiocarbamate, followed with the directly introduceintroduction of PVAc and PNVP polymer side chains onto PNIPAM backbone under thecontrolled manner. The molecular weight, composition, side length and distribution ofthe graft copolymers can be controlled with the characteristic properties of LRPtechnique. By the way, the grafting density also can be adjusted by the feed radio of[t-BuOK]₀/[NIPAM]₀. Gel permeation chromatography,¹HNMR, and ultraviolet visible（UV-vis） were used to confirm the structure and investigate the properties of the graftcopolymers. All the graft copolymers showed narrow molecular weight distributions.Interestingly, the lower critical solution temperature （LCST） of the graft copolymers inaqueous solutions changed with the increase of nVAcand nNVPin the graft copolymers. （2）Three well-defined azobenze homopolymers, e.g. poly{6-[4-（phenylazo）phe-noxy]-hexylmethacrylate}（PPPHM）, poly{6-[4-（4-methoxyphenylazo）phenoxy]-hexyl-methacrylate}（PBPHM） and poly{6-[4-（4-cyanophenylazo）phenoxy]-hexylmethacrylate}（PCPHM） were synthesized via RAFT polymerization using CPDB as the RA-FT agent and AIBN as the initiator. The polymerization showed characteristics ofliving/controlled behavior. The polymer structure and molecular weight were characterized via¹HNMR and GPC technique, respectively. The light responsive behaviors of the homopolymers in their solution were also investigated.