基于原位红外光谱法的聚氨酯热熔胶湿固化动力学研究

An In-Situ Infrared Spectroscopic Study on the Moisture-Curing Kinetics of Polyurethane Hot-Melt Adhesives

采用傅里叶变换原位红外光谱技术研究了聚氨酯热熔胶湿固化反应表观动力学。设计了一种可实现湿度精准控制的原位池,提出了一个能够替代称重法研究湿固化反应动力学的原位红外研究策略。在85%相对湿度下,通过-NCO官能团的变化规律进行动力学分析。结果表明:在研究的温度范围内,聚氨酯热熔胶湿固化速率随着温度升高而加快;在反应初期低转化率时(40%以内),湿固化过程符合一级反应动力学,拟合计算得到活化能为38.17 kJ/mol。聚氨酯热熔胶湿固化反应动力学行为的研究对聚氨酯热熔胶的应用具有重要指导作用。

The kinetics of polyurethane hot-melt adhesives moisture-curing was studied by in-situ Fourier transform infrared spectroscopy(FTIR).An in-situ cell was designed for precise control of humidity.An in-situ infrared method was proposed to study the kinetics of moisture curing reaction instead of the gravimetric method.The kinetic analysis was carried out using the variation law of the-NCO functional group at a constant humidity of 85%.The results showed that the moisture-curing rate of polyurethane hot melt adhesive increased with increasing temperature in the studied temperature range.And the moisture curing process conformed to the first-order reaction kinetics when the conversion was low(within 40%)at the beginning of the reaction,the activation energy by fitting was 38.17 kJ/mol.The study on the kinetics behavior of moisture-curing of polyurethane hot-melt adhesives has an important guiding role in the application of polyurethane hot melt adhesive.