共聚高分子混合物的分子热力学模型

以硬球链流体的分子热力学模型为基础 ,引入方阱位能相互作用的贡献 ,建立了共聚高分子混合物的分子热力学模型 .模型中具有物理意义的链节参数 (链节数、链节直径和链节间的相互作用能 )由纯物质的pVT关系拟合得到 ,而用来校正交叉作用能和交叉碰撞直径的可调参数需由液液平衡的实验数据回归得到 .采用了相对简单的处理方法来确定这些可调参数 .对所选共聚高分子混合物的共存曲线、互溶窗和互溶图等相行为的关联结果令人满意 .

MOLECULAR THERMODYNAMIC MODEL FOR COPOLYMER MIXTURES

A molecular thermodynamic model for copolymer mixtures has been established by combining a reference term for hetero nuclear hard sphere chain fluids with Alder et al. 's square well attractive potential served as a perturbation term. The segment parameters of polymer (including segment number, segment diameter and interaction energy between segments) can be obtained by fitting pVT data of pure homopolymer. The adjustable interaction parameters between segments of polymers can be determined from liquid liquid equilibrium data. This model can be used to correlate coexistence curves for homopolymer/copolymer systems. The effect of copolymer composition on lower critical solution temperature (LCST) and phase separation temperatures are investigated and compared with experiment results for A r-1 /(C X D 1- X ) r-2 copolymer mixtures. For (A X B 1-X ) r 1 /(A Y B 1- Y ) r-2 copolymer mixtures, the interaction parameters between segments of polymers can be obtained from the boundary between miscible and immiscible regions. It was found that the model can satisfactorily be used to correlate phase behaviour including coexistence curves, miscibility windows and miscibility maps for (A X B 1-X ) r 1 /(C Y B 1- Y ) r-2 copolymer mixtures, only a pair of adjustable interaction parameters need to be determined from the boundary between miscible and immiscible regions.