聚丙烯酸接枝辛基酚聚氧乙烯醚的合成、表征和胶束化

通过自由基聚合, 丙烯酸(AA)与辛基酚聚氧乙烯醚丙烯酸酯活性大单体(C8PhEO10Ac)共聚，合成了以聚丙烯酸为主链、C8PhEO10Ac 为支链的水溶性两亲接枝共聚物(PAA-g-C8PhEO10Ac), 用凝胶渗透色谱(GPC)测定其相对数均分子质量为4.37×10⁴, 用FTIR和1H-NMR表征了共聚物的结构和组成, 共聚物分子中丙烯酸单体与活性大单体的摩尔比为9:1, 每个共聚物分子中平均约有32个C8PhEO10侧链. 用表面张力法、荧光探针法和透射电子显微镜对共聚物在水溶液中的自组装行为进行了初步研究, 结果表明, 共聚物分子在第一临界胶束浓度cmc1)和第二临界胶束浓度(cmc2)时都形成了球型胶束. 与cmc1时相比, cmc2时溶液表面张力进一步降低, 胶束内部极性进一步减小, 而且胶束粒径增大、结构紧密. 氯化钠的加入可使共聚物溶液的表面张力和胶束内部极性降低.

Synthesis, Characterization and Micellization of Poly(acrylic acid)-g-Octylphenyl Polyoxylethylene Ether

An amphiphilic graft copolymer PAA-g-C8PhEO10Ac with poly(acrylic acid) as a main chain and octylphenyl polyoxylethylene ether(C8PhEO10) as graft chains was synthesized via free radical copolymerization of acrylic acid (AA) and amphiphilic C8PhEO10Ac maromonomers. The number average molecular weight of the copolymer was determined to be 4.37×10⁴ by gel permeation chromatography(GPC). The structure and composition of the copolymer obtained were characterized by FTIR and 1H-NMR. The molar ratio of acrylic acid monomer to macromonomer is 9:1 in the copolymer and 32 C8PhEO10 branch chains attach to a poly(acrylic acid) backbone. Self-assembly behavior of PAA-g-C8PhEO10Ac in aqueous solution was preliminary studied by means of surface tension measurements, fluorescent probe and TEM. It was found that spherical micelles are formed in water phase at cmc1 and cmc2. As compared with those at cmc1, the surface tension of the copolymer solution and the polarity in the micellar core further decrease at cmc2. Furthermore the diameter of the micelles increases and the micelles become compact. The presence of 1.0%(w) sodium chloride results in the lower surface tension of the copolymer solution and the weaker polarity in micellar core.