摘要
研究了分光光度法测定聚氨酯中微量异氰酸酯基的方法。以N,N-二甲基甲酰胺(DMF)为溶剂,在冰醋酸(HAc)存在下,异氰酸酯基与二甲氨基苯甲醛(DMAB)形成有色化合物,该有色化合物的最大吸收波长为430 nm,表观摩尔吸光系数ε=2.80×104 L·mol-1·cm-1。在430 nm波长下,NCO基团浓度在0-20μg/10 mL范围内符合比尔定律。该方法用于聚氨酯中微量游离异氰酸酯基的测定,相对标准偏差小于5％,具有简便、快速、准确、可靠的特点。
The spectrophotometric determination of isocyanate-group in polyurethane were studied. In presence of acetic acid, NCO reacts with dimethylaminobenzaldehyde(DMAB) in DMF to form a stable yellow compound. Maximum absorption wavelength of the compound is 430 nm and the apparent molar absorptivity is 2. 80×104L· mol-1·cm-1. Beer's Law is obeyed for NCO in the range of 0-20 μg/10 mL.The relative standard deviation(RSD) of this method is less than 5 % and this method has been used to determine trace amounts of NCO in polyurethane with satisfactory results.
出处
《聚氨酯工业》
2003年第4期49-51,共3页
Polyurethane Industry
