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采用拟二元方法研究等规聚丙烯(iPP)-邻苯二甲酸二丁酯(DBP)-邻苯二甲酸二辛酯(DOP)三元聚合物溶液的热致相分离热力学,得出了拟二元相图的数学关联方法.采用光学显微镜法测定浊点温度,采用差式扫描量热法(DSC)测定熔点、动态结晶温度.利用浊点测定数据回归聚合物共溶剂的交互作用参数χ的表达式,χ是共溶剂配比和温度的函数,以此为基础计算的拟二元相图与实验数据吻合较好.发现共溶剂中DBP份数增加,相分离类型由单纯固液分相形式转变为液液分相、固液分相依次发生形式,共溶剂配比能调控拟二元相图结构.研究表明,只需测定一个较低冷却速率下几种共溶剂配比的拟二元溶液的浊点温度、分别测定几个冷却速率下iPP$CDOP二元溶液的动态结晶温度即可掌握该三元溶液热致相分离热力学的全部信息.其可用来指导制膜过程,并能准确预测形成的膜结构形貌.
The pseudo-binary method was used to study the thermotropic phase separation thermodynamics of iPP-DBP-DOP terpolymer solution. The method of mathematical correlation of pseudo-binary phase diagram was used to determine the cloud point temperature by optical microscopy and differential scanning calorimetry (DSC) to measure the melting point and dynamic crystallization temperature.The cloud point data was used to regress the interaction parameters of the polymer co-solvent χ expression, χ is a function of co-solvent ratio and temperature, and the calculated pseudo-binary phase diagram is in good agreement with the experimental data.It is found that the DBP fraction of cosolvent increases and the phase separation type consists of simple solid-liquid Phase separation into liquid-liquid phase-separation and solid-liquid phase-separation in turn, and the co-solvent ratio can control the structure of quasi-binary phase diagram.The results show that only the determination of the ratio of several co-solvents at a lower cooling rate The cloud point temperature of quasi-binary solution can be used to determine the dynamic crystallization temperature of iPP $ CDOP binary solution at several cooling rates, which can be used to guide all aspects of the thermodynamic phase separation thermodynamics of the ternary solution, And can accurately predict the formation of the membrane structure .