部分水解聚丙烯酰胺/柠檬酸铝交联体系粘度在反应过程中的变化规律

VISCOSITY CHANGE OF PARTIALLY HYDROLYZED POLYACRYLAMIDE-ALUMINUM CITRATE SYSTEMIN CROSSLINKING REACTION

利用奥氏粘度计研究了部分水解聚丙烯酰胺 /柠檬酸铝交联体系在反应过程中的粘度变化规律 ,结果表明 ,不同浓度的部分水解聚丙烯酰胺与柠檬酸铝在交联反应过程中的粘度主要呈现 3种形式的变化规律 ,对应形成3种形式的交联体系。低聚合物浓度 (低于 10 0mg/L)的交联体系 ,发生形成交联聚合物线团的反应 ,形成交联聚合物溶液 ,是交联聚合物线团在水中的分散体系 ;高聚合物浓度 (高于或等于 10 0 0mg/L)交联体系发生网状交联反应 ,生成网络结构整体凝胶 ;弱凝胶体系 (10 0～ 70 0mg/L)是上述两种体系的过渡状态 ,可同时发生交联聚合物线团反应和局部网状交联反应。对于一定聚合物浓度范围的交联体系 ,当反应过程中生成浓度较大、但仍有一定独立性的交联聚合物线团时 ,该体系出现明显的剪切稠化现象。考察了该交联体系出现剪切稠化现象的程度和浓度范围 ,并利用粒子簇理论对剪切稠化现象进行了初步探讨。交联体系在反应过程中的剪切稠化现象初步验证了不同聚合物浓度交联体系的反应机理。

The viscosity change of partially hydrolyzed polyacrylamide (HPAM) and aluminum citrate (AlCit) cross-linked system in the process of cross-linking reaction was measured by the use of viscometer. The results show that partially hydrolyzed polyacrylamide and aluminum citrate with different concentrations have three kinds of changes in viscosity in the cross-linking reaction and correspondingly formed three kinds of cross-linked systems. The cross-linked system with low-concentration (below 100 mg/L) polymer could form linked polymer solution (LPS). The cross-linked system with high concentration (over 1000 mg/L) can generate network gel and bulk gel with different rheological properties. The experiments showed that there existed shear-thickening phenomena in the cross-linked polymer system. The shear thickening degree and the range of corresponding concentration were investigated, and some mechanism was discussed. The results showed that the shear thickening phenomena could appear when the cross-linked polymer coils with sufficient concentrations formed in the cross-linked system.