作　　者： ; ; ; ; ; ; (夏必来）;

机构地区： 武汉大学化学与分子科学学院

出　　处： 《化学学报》 2007年第23期2656-2662,共7页

摘　　要： 采用大分子单体法制备接枝型两亲共聚物,通过表面张力仪、偏光显微镜、旋转流变仪和小角X射线衍射研究了两亲共聚物在水溶液中的聚集行为及其相结构.首先末端带有可聚合双键的聚甲基丙烯酸叔丁酯大分子单体(PtBMA Macromonomer)通过催化链转移聚合法制备,所用到的催化链转移剂为二水合双(二氟化硼苯二酮肟)合钴(II)(COPhBF).然后将所得到的大分子单体与丙烯酸正丁酯(BA)进行自由基共聚得到接枝共聚物PBA-g-PtBMA,PBA-g-PtBMA中PtBMA的侧链部分在酸性条件下定量水解成聚甲基丙烯酸(PMAA)并用NaOH中和得到主链疏水侧链亲水的接枝型两亲共聚物PBA-g-P(MAA-Na+).用Wilhelmy吊片法研究了不同浓度的两亲共聚物水溶液的表面张力,发现其行为与小分子表面活性剂不同.同时用动态光散射法测量了两亲共聚物水溶液中聚集体的粒度,发现在研究的浓度范围内(0.02～10g/L)聚集体都存在两个粒度分布峰(约30和300nm).浓溶液(w=37.5%)的偏光显微照片呈现层状液晶的特征图案,而流变研究表明此时体系具有明显的粘弹性,说明体系形成了层状液晶.并且用小角度X射线衍射测定了层状液晶的层间距,约为12.6nm. An amphiphilic graft copolymer was obtained using a macromonomer method and its aggregate behavior and phase structure in aqueous solutions were studied by tensionmetry, polarized micrography, rotation rheometry and small-angle X-ray diffraction. Firstly, the graft copolymer PBA-g-PtBMA was synthe- sized by a free radical copolymerization of butyl acrylate （BA） with poly（t-butyl methacrylate） （PtBMA） macromonomer, which has the vinyl end group and was prepared by a catalytic chain transfer polymerization using bis[（difluoroboryl）diphenylglyoximato] cobalt（II） （COPhBF） as the chain transfer catalyst. Then PtBMA segment in the graft copolymer PBA-g-PtBMA was quantitatively hydrolyzed under an acidic condition and neutralized by NaOH solution to prepare the amphiphilic graft copolymer PBA-g-P（MAA-Na^＋） with hydrophobic backbone and hydrophilic side chains. The surface tension of aqueous solutions with different concentration of amphiphilic copolymer was measured by Wilhelmy plate method. The plot of surface tension vs. concentration was different from that of typical surfactants. The aggregate diameters measured by a dynamic light scattering method had double peaks （with peak values of 30 and 300 nm） and kept nearly constant during the concentration from 0.02 to 10 g/L. Polarized micrograph of the arnphiphilic copolymer solution （w=37.5%） showed the typical lamellar liquid crystalline pattern. And the concentrated solution exhibited distinct viscoelastic property. The interlayer space （about 12,6 nm）, was measured by small-angle X-ray diffraction.

关 键 词： 催化链转移聚合 接枝型两亲共聚物 聚集体 粘弹性 层状液晶 小角度 射线衍射

领　　域： [理学] [理学]