利用等温等压下的分子动力学模拟方法预测了60wt%甘油水溶液的玻璃化转变温度(Tg)。在90-250K的温度范围内,模拟计算体系的宏观物理量如恒压热容、密度、周期性单元体积、特征原子的径向分布函数和氢键的形成几率等状态参数,通过这些参数随温度的变化规律来预测甘油水溶液的马值。结果表明:60%的甘油水溶液的预测马值(160.06-167.51K)与DSC实验测定结果(163.60-167.10K)和DMA实验测定结果(159K)十分吻合。
The glass transition temperature (Tg) of the glycerol aqueous solution (60 wt/%) was determined by isothermal-isobaric molecular dynamic simulation (NPT-MD). The state parameters of heat capacity at constant pressure (Cp), density (p), amorphous cell volume (Vcell) and specific volume (Vspecific) were obtained by NPT-MD at the temperature range of 90-250 K. These parameters showed a discontinuity at a specific temperature in the state parameter versus temperature plot. The specific temperature is taken as the simulated Tg. It is shown that the simulated Tg (160.06-167.51 K) agrees well with the DSC results (163.60-167.10 K) and the DMA results (159 K).