Mark-Houwink方程中系数的意义及应用探索——K值的意义及对高分子特性的评估

A STUDY AND APPLICATION OF THE COEFFICIENTS OF MARK-HOUWINK EQUATION ——THE MEANING OF K AND A RELATED APPROACH FOR ESTIMATING THE POLARITY OF POLYMER

K值是Mark Houwink经验公式 ([η]=KMα)中的两个常数之一 .理解它的意义不仅有利于公式的应用 ,而且有可能有利于从不同的角度认识高分子材料的性质 .考虑到K是由高分子材料和使用的溶剂性质所决定的 ,因此引入溶剂的一些参数对Mark Houwink经验公式中的K的意义进行了初步探讨 .结果显示 ,高聚物的K和溶剂的极性参数 ,如Reichardt的Et(30 )及Kamlet Taft的π 之间有一定的线性关系 ,而根据这些关系外推发现所有这些被引用的高分子材料似乎可以由此被划分成两大类 ,并进一步推导出高分子材料的极性 .此简易方法得出的数据得到文献和近来的有关研究结论的认可 .

K value is one of the parameters of the Mark-Houwink equation. In principle, the understanding of the meaning of this parameter is not only of benefit to the application of the equation, but may also provide possibility for learning the polymer-solvent interactions. By importing several polarity parameters of solvents, e. g. the Kamlet-Taft's pi* and Reichardt' s E-t ( 30), it was reported that these polar parameters were related with the K values. Especially, it was found that one can directly estimate the polarity of polymers based on the plots of K versu pi* and E-t (30), respectively. These plots scowed good linear relationships with positive or negative slopes. The estimated polarity values of polymers were compared with those reported in literature, and the primary results seemed reasonable.