Abstract: According to thermodynamic relation that the pressure of polymer liquids is the difference between thermal pressure and internal pressure,and the experimental isochors are good straight lines,an equation of state for polymer liquids is established. The thermal pressure is obtained by the principle of corresponding state and the internal pressure is derived from Lennard-Jones(6,12) potential. The equation of state contains three characteristic parameters which have clear physical significance and can be satisfactorily used to correlate pVT data of various polymer liquids. The correlation results with 18 homopolymers and 4 copolymers show that the total average absolute deviation of specific volume is 0.00042 cm³•g^-1 for the range of pressure from 0—50 MPa and 0.00063 cm³•g^-1 for full range of experimental pressure. This correlation results are better than those of the Simha-Somcynsky equation.

Key words: 液态聚合物, 状态方程, 热压力系数, 内压力

摘要： 由热力学关系建立了一个液态聚合物的状态方程.聚合物的热压力由对应状态原理得到，内压力由Lennard-Jones(6,12)势能函数导得.状态方程包含3个有明确物理意义的特性参数，能够满意地关联各种液态聚合物的pVT数据.对18个均聚物和4个共聚物的比体积关联结果表明，总的平均绝对偏差在0～50 MPa压力范围内为0.00042 cm³•g^-1，在全部实验压力范围内为0.00063 cm³•g^-1，优于Simha-Somcynsky方程算得的结果.

关键词: 液态聚合物, 状态方程, 热压力系数, 内压力