用TGA技术分析阳离子水性聚氨酯的热行为

Study on Thermal Behavior of Cation Waterborne Polyurethane by TGA Technology

在不同升温速率条件下研究了阳离子水性聚氨酯在氮气中的热失重过程,用等转化率和主曲线法得出失重过程的活化能和动力学方程。实验得出阳离子水性聚氨酯的热失重温度范围为160~350℃;失重过程分两个阶段完成,第一阶段失重范围为0~55%,活化能为83.46kJ.mol-1,机理函数积分式为G（α）=[1-（1-α）1/2]2,第二阶段失重范围为60%~100%,活化能为95.61kJ.mol-1,机理函数积分式为G（α）=α＋（1-α）ln（1-α）。在失重为55%~60%之间两步重叠。

The thermal behavior of cation waterborne polyurethane（CWPU） was investigated by non-isothermal method and thermogravimetry（TG） technique in N2 atmosphere.The iterative iso-conversional methods were applied to calculate the activation energy Ea of dehydration and decomposition,and the most probable mechanism function G（α） was determined by means of the master plots method.The weightlessness of CWPU proceeds to completion by two distinct reactions.These two reactions overlap in the transition process（55%〈α〈60%）.Kinetic parameters of the first reaction of weightlessness were：Ea =83.46kJ·mol-1,lnA/s-1 =19.78,and the mechanism function wasG（α）=[1-（1-α）1/2]2.And in the second reaction Ea = 95.61 kJ·mol-1,lnA/s-1=16.94,G（α）= α＋（1-α）ln（1-α）.