黏度法测分子质量中空白溶液流出时间的确定  

Determination of time for blank solution in molecular weight measurement by viscometry

作　　者：赵宏宇[1] 刘够生[1] 王丽娟[1] 孟君[1] 于建国[1] 

机构地区：[1]华东理工大学资源过程工程研究所,上海200237

出　　处：《无机盐工业》2009年第3期52-55,共4页Inorganic Chemicals Industry

基　　金：国家十一五科技计划重点项目(2008BAE58B03)

摘　　要：当聚合物溶液流过乌氏黏度计的毛细管时，由于聚合物分子在毛细管表面吸附，该表面的物理和化学性质将发生很大的改变，尤其是当溶液中含有大量的电解质时这种情况更为突出。毛细管的有效直径降低了，在测量不同质量浓度的溶液前后测量空白溶液的流出时间会不一样，这样就导致最后得出的结果黏均分子质量不同。虽然这个空白溶液的流出时间有它的重要性，但是没有广泛适用的方法来确定它。如果继续使用现有的方法，随着质量浓度的降低，ηsp/ρ与ρ不再是线性的关系。为了重新找到使它们成为线性关系的方法，使用了质量浓度较小的稀溶液，质量浓度范围为（0．5～5．0）×10^-3／mL，又在溶液中加入了电解质，并使用一个推论得到的测定方法。从对含有电解质的溶液的理论分析和实验数据来看，推论出的方法具有更宽的实用性和准确性，从而使ηsp/ρ与ρ在更宽的稀溶液质量浓度范围内又成为直线关系。While polymer solution flows through the capillary of Ubbelohde viscometer, the adsorption of polymer molecules on the surface, sometimes, seriously changes the physical and chemical properties of the surface, especially when electrolyte is added into the solution. The effective diameter is narrowed. Thus, time for blank solution to flow through the capillary is different before and after measuring time of the solution with varied mass concentration, making the average molecular weight strikingly different. Despite importance of the time for blank solution, no uniformly adopted method has been established to determine it. However, for the currently used methods,ηsp/p is no longer the linear function p as the concentration decreases. To make the linear correlation again, a solution of a wide range of low mass concentration was prepared （0.5～5.0）×10^-3/mL, and addition of electrolyte was considered. A method to determine the time for blank solution was proposed. Theoretical analysis and experimental data of polymer molecules in solution containing electrolyte showed that this method is more applicable and accurate, making ηsp/ρ the linear function of ρ at wider range of low concentration.

关 键 词：聚磷酸铵 乌氏黏度计 黏度法 二次外推 

分 类 号：TQ126.35[化学工程—无机化工]