环氧丁羟环氧值测定方法的研究

Study on determination method for epoxy value of epoxidized hydroxyl-terminated polybutadiene

研究了在盐酸–四氢呋喃介质中,以酚酞–乙醇作指示剂,氢氧化钠溶液返滴法测定环氧丁羟(EHTPB)的环氧值的方法,考察了反应时间、反应温度、反应介质、指示剂对结果的影响。最终确定了在常温下,EHTPB样品在盐酸–四氢呋喃[V(盐酸):V(四氢呋喃)=1:40]介质中搅拌溶解后静置30min,以10g/L酚酞–乙醇作指示剂,0.15mol/L氢氧化钠溶液返滴测定其环氧值的方法。对该方法的精密度和重现性进行分析,测定结果的相对标准偏差均小于1.50%。该方法具有良好的准确度。

Using the phenolphthalein-ethanol as indicator,the method for determining epoxy value of epoxidized hydroxyl-terminated polybutadiene(EHTPB)in hydrochloric acid-tetrahydrofuran medium by using the back titration method with sodium hydroxide solution was studied.The influence of reaction time,reaction temperature,reaction medium and indicator on the results was investigated.Finally,the method was confirmed as follows:the EHTPB sample was dissolved with stirring in hydrochloric acid-tetrahydrofuran[V(hydrochloric acid):V(tetrahydrofuran)=1:40]medium at room temperature,and then placed for 30min,using 10g/L phenolphthalein-ethanol as indicator,the epoxy value was determined by the back titration with 0.15mol/L sodium hydroxide solution.The precision and reproducibility of said method were analyzed,the relative standard deviations of the determination results are all less than 1.50%.The method possesses good accuracy.