摘要
研究了分光光度法测定聚氨酯胶粘剂中异氰酸酯基(NCO)含量的方法。以N,N二甲基甲酰胺(DMF)为溶剂,在冰乙酸(HAc)存在下,异氰酸酯基与N,N对二甲氨基苯甲醛(DMAB)形成有色化合物,该有色化合物的最大吸收波长为450nm,表观摩尔吸光系数ε=1.31×105L·mol-1·cm-1,NCO基团浓度在0～10μg/5mL范围内符合朗伯比尔定律。该方法用于聚氨酯胶粘剂中微量游离NCO基团的测定,相对标准偏差小于5%,具有快速简便、可靠准确的特点。
Spectrophotometric determination of free isocyanate-group in polyurethane adhesive was 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 450 nm and the apparent molar absorptivity is ε=1.31×105L ·mol -1 · cm -1 . Beer’s Law is obeyed for NCO in the range of 0~10 μg/5mL. The relative standard deviation of this method is less than 5% and this method has been used to determine the free isocyanate-group in MDI polyurethane adhesive.
出处
《聚氨酯工业》
2005年第3期39-42,共4页
Polyurethane Industry
