表面张力对PEO稀溶液粘度行为的影响

测定了不同分子量聚氧化乙烯 (PEO)在水和苯溶剂中的粘度 ,发现在低浓度区PEO水溶液的比浓粘度出现负偏离 ,PEO苯溶液比浓粘度与浓度之间依旧满足线性关系 .表面张力测定结果表明 ,PEO分子显著降低了水的表面张力 ,而苯的表面张力则不受影响 .PEO水溶液和纯溶剂水表面张力的不同干扰了高分子溶液和溶剂在粘度计中流过时间的测量 ,导致低浓度区PEO水溶液比浓粘度出现负偏离 .利用PEO水溶液和水表面张力测定结果 ,结合乌式粘度计的几何尺寸 ,定量分析了PEO水溶液和纯溶剂水表面张力的差异对粘度测量结果的影响 ,计算结果与实验结果基本相符 .如果用PEO水溶液流过时间对浓度作图的外推值t0 计算相对粘度 ,可以完全消除PEO水溶液和水表面张力差异对粘度测量的影响

Effects of the Surface Tension upon the Viscosity Behavior of Dilute PEO Solutions

The viscosity behavior of poly(ethylene oxide)(PEO) with different molecular weights in the water and benzene was determined respectively. It was noted that the reduced viscosity of PEO in the water deviated negatively from the linear relationship at lower concentrations in the reduced viscosity versus concentration plot. On the other hand, the reduced viscosity of PEO in benzene increased linearly with concentration even at lower concentrations. The surface tension measurements indicated that PEO could reduce the surface tension of water considerably but had no effect on the surface tension of benzene. The influence of the surface tension upon the viscosity behavior of polymer solution was notable, especially when the surface tension between the polymer solution and the pure solvent was significant. By measuring the surface tension of water and aqueous PEO solution, together with the geometric parameter of the viscometer, the influence of the surface tension upon the measurement of the flowing time could be studied quantitatively. The calculations were consistent with experimental results approximately. If t 0 * was employed to determine the viscosity of polymer solution, the influence of the surface tension upon the viscosity behavior of polymer solution could be counteracted completely and the reduced viscosity of PEO in water increased linearly with concentration just the same as PEO in benzene.