两亲性ABA三嵌段共聚物的合成及其自组装行为研究  

SYNTHESIS AND SELF-ASSEMBLY OF AMPHIPHILIC ABA TRIBLOCK COPOLYMER via COMBINATION OF ROMP AND ATRP

作　　者：谢美然[1] 韩会景[1] 孔毅[1] 李金欣[1] 张以群[1] 

机构地区：[1]华东师范大学化学系,上海200062

出　　处：《高分子学报》2009年第4期345-351,共7页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20474017)资助项目

摘　　要：用Grubbs第二代催化剂引发降冰片烯类单体(NBEDE)和链转移剂在离子液体[bmim][BF4]中的开环易位聚合(ROMP)反应,反应体系保持均相,无聚合物析出,得到两端为叔溴的遥爪型官能化聚合物(Br-PNBEDE-Br).以Br-PNBEDE-Br作为大分子引发剂,在离子液体介质中引发甲基丙烯酸2-(二甲氨基)乙酯(DMAEMA)的原子转移自由基聚合(ATRP),制得分子量分布较窄的两亲性三嵌段共聚物(PDMAEMA-PNBEDE-PDMAEMA).利用动态激光光散射(DLS),原子力显微镜(AFM),透射电镜(TEM)等技术,考察嵌段共聚物在选择性溶剂/共溶剂(H2O/THF)中的胶束行为,以及溶液pH值对胶束的影响.结果表明,TEM观察到胶束为球形,由于TEM和AFM是在干态下测得胶束的粒径,而DLS是在溶液中测定胶束的流体力学直径,所以TEM和AFM得到的胶束粒径小于DLS的结果.不同pH值对胶束尺寸大小有明显的影响,胶束微粒随着pH值的增大而增大.Ring-opening metathesis polymerization （ROMP） with functionalized chain transfer agent （CTA） for the preparation of telechelic polymers has the ability to control the polymer molecular weights through varying the ratio of monomer to CTA. The bromo-terminated teleehelic polymer （Br-PNBEDE-Br） was prepared via ROMP of norbomene derivative, in conjunction with a CTA in[ bmim] [ BF4 ]. The obtained polymer was characterized by ^1H- NMR spectroscopy. The alkene proton signals of the norbornene ring appeared approximately at δ = 6.24. Upon ring- opening and subsequent polymerization, these proton signals shifted upfield to approximatelyδ= 5.64 - 5.16, this indicated the polymerization had occurred. The resonances of methylene protons adjacent to the ester bond （CH CHC_H2OCO） shift from δ= 4.82 in the CTA to δ = 4.56 in the polymer. These characteristic X H-NMR resonances indicated that the CTA have been incorporated into the polymer chain. Furthermore, other types of end-groups were not observed in their expected regions of the ^1H-NMR spectroscopy. Thus, the polymer should be a difunetionalized telechelic polymer with a high degree of bromine end functionalization. Based on using of the bromo-terminated teleehelic polymer as macroinitiator, amphiphilic ABA triblock copolymer was synthesized by atom transfer radical polymerization （ATRP） of 2-（dimethylamino）ethyl methaerylate （DMAEMA） in [bmim] [BF4]. The formation of the copolymer was verified through the characteristic resonances of OCH2 CH2 N and N（ CH3 ）2 protons from the block of PDMAEMA at δ = 2.63 - 2.52 （Hp） and δ = 2.35 - 2.24 （ Hq ）, respectively, and resonances of methyl protons of C （ CH3 ） from the same block at δ = 1.12 ～ 0.80 （ Hk ） . The integration area ratios of these characteristic resonances of 2.00 ： 5.96 ： 2.92 were well agreed with the ratios of corresponding protons of 2 ： 6 ： 3. The molecular weights of the copolymers were calculated by comparing the integral intensity of the meth

关 键 词：开环易位聚合(ROMP) 原子转移自由基聚合(ATRP) 链转移剂 嵌段聚合物 自组装 

分 类 号：O631.3[理学—高分子化学]