疏水修饰聚丙烯酸共聚物在水溶液中的缔合作用

丙烯酸类共聚物具有良好的增稠，分散，成膜和絮凝等性能，因而在涂料，皮革，油漆，颜料及油田开发等领域具有广泛的用途^1]，但当体系中可溶性盐类含量高时，该类水溶性大分子的使用效果不降，而疏水修饰共聚物可克服原聚合物对高价金属离子敏感的缺陷^2]，疏水修饰共聚物在水溶液中可缔合成胶束状团簇（MLCs)，造成大分子的流体动力学尺寸增大，从而使溶液粘度增大，MLCs的疏水微区可增溶油类物质，因此疏水修饰大分子可作为含高价离子浓度体系的流度控制剂^3]，本文利用荧光探针技术^4,6]探讨了丙烯酸丁酯－丙烯酸－甲基丙烯酸共聚物在纯水和盐水溶液中的缔合作用。

Association of Copolymer Acrylic Acid/Methyl-acrylic acid/Butyl Acrylate in Aqueous Solution

The associations of triblock copolymer made of acrylic acid, methyl-acrylic acid and butyl acrylate in aqueous solution as well as in NaCl and CaCl₂ solutions were studied by using fluorescence. The micelle-like clusters(MLCs) of copolymer formed is able to solubilize non polar material. Alittle electrolytes added in the copolymer solution can increase the value of critical aggregation concentration( ρ_ac ) and micropolarity. But with the increase of the concentration of electrolytes, the value of ρ_ac and micropolarity will decrease. When there is NaCl with fixed concentration in the systems, the process of the MLCs loosening is relaxed because of the charge-screening. In the systems with fixed CaCl₂ concentration, Ca ²⁺ induced the cross-link of -COO^-groups, so the interface between the MLCs and the water is not obvious and the big MLCs is formed between the clusters.