分光光度法测定有机硅改性聚氨酯涂料印花粘合剂中异氰酸酯基含量

摘要

In N, N-dimethylformamide (DMF) solution with glacial acetic acid (HAc), the collored compound was formed by reaction of isocyanate and N, N-dimethylamino-benzaldehyde (DMAB).The best absorption wavelength of the colored compound was determined at 440 nm through experiments.The acidity of the system,dosages of developer and developing time factors were investigated.The spectrphotometry method was established to detect the content of isocyanate content in silicone-modified polyurethane pigment printing binder.The equation of linear regression was y = 0.017 7 x + 0.171 9, and the correlation (R2) was = 0.999 6.The recovery rate of this method were 94.29％～104.14％, and the standard deviation was less than 1 ％.This method was convenient and accurate.%在N,N-二甲基甲酰胺(DMF)的冰乙酸(HAc)介质中,异氰酸酯基与N,N-对二甲氨基苯甲醛(DMAB)形成有色化合物,试验确定该有色化合物的最佳吸收波长为445 nm.考察了体系酸度、显色剂用量、显色时间等影响因素,建立了分光光度法测定有机硅改性聚氨酯涂料印花粘合剂中异氰酸酯基含量的定量分析方法.确定的标准曲线线性回归方程为y=0.0177x+0.171 9,相关系数为R<'2>=0.999 6.该方法的回收率为94.29%～104.14%,相对标准偏差小于1%,具有方便、准确的特点.