水解聚丙烯酰胺溶液粘弹特性的研究

通过锥板测量系统对水解聚丙烯酰胺(HPAM)溶液的粘弹性进行了研究.结果表明, 这种锥板测量系统能较灵敏地检测出溶液粘弹性结构的存在,并得到了聚合物溶液的弹性成份和粘性成份的关系.发现随着HPAM溶液浓度的增大,聚合物溶液的弹性成份起初迅速增大,随后增大的趋势变慢而趋于平缓,在经历一最大值后又略有下降.在剪切速率ṝ =0.36 s－1下,超高分子量的HPAM(M=1.65×107)溶液(c = 1.5 g·L－1)具有明显的粘弹特性;随着盐的加入,溶液的粘弹性下降,当盐浓度达到一定值的时候,溶液内部的网络结构遭到破坏,其弹性行为完全消失.对于聚丙烯酰胺(PAAM, M=2.0×105)溶液(c = 2.0 g·L－1)在剪切速率(ṝ=0.36～1.36 s－1)范围内没有观察到粘弹行为,只在ṝ≥1.65 s－1时,才能观察到微弱的粘弹现象.

Study on Viscoelastic Properties of Partially Hydrolyzed Polyacrylamide Solution

In this paper, the viscoelastic properties of partially hydrolyzed polyacrylamide(HPAM) solution were investigated with a cone-and-plate measuring system. Results show that the existence of viscoelastic structure in HPAM solution can be detected quite sensitively by the apparatus. Meanwhile, we also obtained the relationship between the elastic component and the viscous component. It is shown that there exists a maximum value corresponding to the elastic component of solution at the HPAM concentration range of 0.1～0.4 g·L－1. At shear rate ṝ=0.36 s－1, high molecular weight hydrolyzed polyacrylamide solution has apparent viscoelastic properties. With the addition of salts, viscoelastic properties of HPAM solution decrease. Moreover, the network structures in HPAM solution are destroyed at higher salt concentration, and the elastic behaviors vanish. For PAAM(polyacrylamide) solution, viscoelastic properties weren′t observed at the range of 0.36～1.36 s－1. A weak viscoelasticity was observed only when ṝ ≥1.65 s－1.