DTA中升温速率及样品热导率对T_g测量值影响的模拟研究

就不同升温速率和实际样品的不同热导率对差热分析 (DTA)中高分子材料的玻璃化转变曲线的影响进行了MonteCarlo模拟研究 ,发现当所有样品刚完成玻璃化转变时 ,在Tg 曲线中该特征点要低于Tg 的转变中点。转变中点所对应的样品温度肯定要高于实际的玻璃化转变温度。如果以玻璃化转变曲线的转变中点所对应的样品温度作为该材料的玻璃化转变温度 ,那么 ,升温速率越快、样品的热导率越小 ,所测得的玻璃化转变温度就越大 ,反之亦然。DTA测得的玻璃化转变温度与升温速率间有很好的线性依赖关系 ,但与样品热导率间的关系是非线性的

Simulation of the Effects of Heating Rate and Thermal Conductivity of Polymer on the Experimental Values of Glass Transition Temperature in Differential Thermal Analysis

For different heating rates of stove and different thermal conductivity coefficients of polymers, the Monte Carlo simulation of differential thermal analysis (DTA) on the glass transition was carried out. The simulation results reveal that the temperature corresponding to the midpoint of the glass transition curve is the function of experimental conditions and is higher than actual glass transition temperature (T g). If this temperature was taken as T g, then, the quicker the heating rate and the smaller the thermal conductivity coefficient of polymers, the bigger the T g,vice versa. There are good linear relations between the T g obtained in DTA and the heating rate of stove. The nonlinear relations between T g and thermal conductivity coefficients of sample are also obtained.