PMIA树脂溶液中盐酸含量的测定

Determination of hydrochloric acid content in PMIA resin solution

分别以乙酸钠-甲醇溶液、氢氧化钾-甲醇溶液为滴定剂,采用电位滴定法测定不同中和程度的聚间苯二甲酰间苯二胺(PMIA)树脂溶液中盐酸含量,并对2种测试方法的准确度和精密度进行比较。结果表明:采用2种测试方法测定中和程度分别为0、60%、95%、100%的PMIA树脂溶液中盐酸含量,2种测试方法的测定结果相近;采用F检验和t检验两种统计法验证了显著性水平为0.05、置信度为95%时2种测试方法的准确度和精密度均无显著差异,以氢氧化钾-甲醇溶液为滴定剂的测试方法的精密度更高;采用标准盐酸加入法,并以氢氧化钾-甲醇溶液为滴定剂测定不同中和程度的PMIA树脂溶液中盐酸回收率,平均回收率为96.5%~98.5%,验证了该方法的准确性;对于正常滴定过程中等当点不易识别的PMIA树脂溶液,可通过预加已知量的盐酸后再采用氢氧化钾-甲醇溶液滴定,从而确定溶液的酸碱性。

Using sodium acetate-methanol solution and potassium hydroxide-methanol solution as titrants,the hydrochloric acid content in poly(m-phenylene isophthalamide)(PMIA)resin solution with different degrees of neutralization was determined by potentiometric titration.The accuracy and precision of the two test methods were compared.The results showed that the two test methods provided the similar test results when used to determine the hydrochloric acid content in PMIA resin solutions with neutralization degrees of 0,60%,95%,and 100%,respectively;two statistical methods,F-test and t-test,were used to verify that there was no profound significant difference in accuracy and precision between the two test methods and the test method using potassium hydroxide-methanol solution as a titrant had higher precision when the significance level was 0.05 and the confidence level was 95%;the average recovery rate was 96.5%-98.5%,verifying the accuracy of this method,when the hydrochloric acid recovery rate of PMIA resin solutions with different degrees of neutralization was determined by standard hydrochloric acid addition method using potassium hydroxide-methanol solution as a titrant;and the acidity and alkalinity of PMIA resin solution,whose equivalent point was difficult to be identified during the normal titration process,can be determined by pre-adding a known amount of hydrochloric acid and then titrating with potassium hydroxide-methanol solution.