采用非水滴定法测定羧基丁腈橡胶中的羧基含量

Determination of carboxyl content in carboxyl nitrile rubber by nonaqueous titration method

建立了一种采用非水滴定法测定羧基丁腈橡胶中羧基含量的方法,并考察了该方法的准确度和精密度。该方法以非水溶剂丁酮溶解试样,然后以KOH-乙醇标准溶液中和,滴加酚酞作指示剂,并用盐酸标准溶液返滴定过量的KOH。测试结果表明,该方法的回收率为97.3%～103.4%,标准偏差不大于0.040%。

A nonaqueous titration method for determinating carboxyl content in carboxyl nitrile rubber was established. The precision and the accuracy of the method were verified. In the method, the sample was dissolved in a sort of nonaqeous solvent 2 - butanone,and the obtained solution was neutralized with KOH -ethanol standard solution,then the indicator phenolphthalein was added dropwise, finally the excess KOH was back -titrated with HCl standard solution. The results showed that the measuring recovery ratio was in the range of 97.3% -103.4% and the standard deviation was no more than 0. 040 %.