聚酯热熔胶的熔融黏度及其Avrami方程表征

Melt viscosity of polyester hot melt adhesive and its characterization by Avrami equation

采用Brookfield黏度计对不同聚酯热熔胶样品进行黏度测试,根据Arrhenius方程得到样品相应的黏流活化能参数,进口样品的活化能值(56,76 k J/mol)大于国内样品(49,48 k J/mol),在低温下条件下国外进口样品的流动性好;通过在一定熔融温度下黏度随时间的变化,引入Avrami方程对其进行黏度随时间的变化表征,发现其lg[-ln(1-Xt)]～lg t关系图呈线性(线性度R=99%),并根据计算得到相关的降解速率常数Zt,温度越高速率常数越大;在发生高温凝胶的样品体系中,其黏度的Avrami方程发生线性偏离。

The viscosity of different polyester hot melt adhesive samples was measured by Brookfield viscometer. According to the Axrhenius equation,the corresponding viscous flow activation energy parameters of the sample were obtained.The activation energy of imported samples (56,76kJ/mol)is larger than that of domestic samples (49,48kJ/mol),and the fluidity of the imported samples is good at low temperature,and the viscosity change with time of imported samples is characterized by introducing Avrami equation by changing viscosity with time at a certain melting temperature.It is found that the 1g[-In(1-Xt)]~1gt diagram is linear (linearity R =99%), The relative degradation rate constant Zt is obtained according to the calculation.The higher the temperature is,the bigger the rate constant is,and the linear deviation of the Avrami equation of viscosity occurs in the sample system with high temperature gel.