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采用流变学法系统地考察了部分水解聚丙烯酰胺 (HPAM) /Cr(Ⅲ )交联体系的反应动力学 .HPAM溶液的粘性模量G″大于弹性模量G′ ,且其数值随时间不发生变化 ,体系为粘性溶液 .而HPAM/Cr(Ⅲ )体系的G′和G″的数值都随时间变化 ,G″在反应开始阶段大于G′ ,当反应进行一段时间后 ,G′超过G″占据主要地位 ,体系成为弹性体系 .交联过程可分为三个阶段 :第一上升阶段 ,平缓上升阶段和第二上升阶段 .利用G′～t曲线可以推测反应机理 .实验发现成胶速率随反应物HPAM和Cr(Ⅲ )的浓度的增加而增加 ,而成胶时间缩短 .在羧基浓度过量的情况下 ,交联反应对Cr(Ⅲ )浓度的反应级数是 1.凝胶的有效弹性交联密度随聚合物浓度的增加而增加 ,且随凝胶反应的进行而增加 .凝胶的交联点间的链平均分子量随Cr(Ⅲ )浓度的增加和交联反应的进行而下降 .
The reaction kinetics of partially hydrolyzed polyacrylamide (HPAM) / Cr (Ⅲ) crosslinked system was systematically investigated by rheological method. The viscous modulus G “of HPAM solution was larger than the elastic modulus G ’ And the system is a viscous solution, while the values of G ’and G ”of the HPAM / Cr (Ⅲ) system all change with time, and G’ ’is greater than G’ at the beginning of the reaction. When the reaction is carried out for a period of time, G ’ G "occupy the main position, the system becomes a flexible system.Crosslinking process can be divided into three stages: the first rising stage, the gentle rising stage and the second rising stage.Using G ’~ t curve can be speculated that the reaction mechanism.Experiments found that the plastic The rate increases with the increase of reactants HPAM and Cr (Ⅲ) concentration, and the gelling time is shortened.When the concentration of carboxyl groups is too high, the reaction order of the cross-linking reaction to Cr (Ⅲ) The effective elastic cross-linking density increases with the increase of the polymer concentration and increases with the progress of the gel reaction.The chain average molecular weight of the cross-linking point of the gel increases with the Cr (Ⅲ) concentration and the cross-linking reaction proceeds Fall.