Abstract: A real chain-like molecule can be approximately described as a square-well chain.The molecular thermodynamic model for chain-like molecule fluids has been established by adopting the molecular thermodynamic model for hard-sphere-chain fluids as a reference and a perturbation term contributed by the square-well potential.It has a very simple form.For pure normal fluidswith no association,good agreement with experimental data can be obtained by using three tem-perature independent molecular parameters:chain length r,segment diameter σ and interaction energy ε/κ between segments,estimated from saturated vapor pressures and liquid volumes.Excluding the critical region,the deviation of vapor pressures is less than 2% for most substances,the deviation of liquid volume is less than 3%.With the same three temperature independent parameters,the specific volume of polymers with a wide range of temperature and pressure can be satisfactorily correlated.The deviations of specific volume with pressures up to 200MPa are less than 0.2%.

摘要： 实际链状流体的分子热力学模型表示为参考流体（硬球链流体）的贡献与一微扰项之和.作者先前建立的硬球链流体的状态方程用于计算参考流体的性质，用Alder等人对方阱流体的计算机模拟结果计算微扰项的贡献，从而建立了实际链状纯流体的分子热力学模型.该模型具有非常简单的形式，用三个与温度无关的分子参数（分子的链数，链节的直径和链节间的方阱位能阱深）可以较好地关联从球形小分子到链状高分子、分子间没有氢键作用的流体的饱和蒸汽压、饱和液体体积和pVT关系