The objective of the research was to provide fundamental thermodynamics data for the development of supercritical fluid assisted polymer devolatilization technology.The equilibrium composition data in a CO2/1,3-Propanediol (1,3-PDO)/Poly(trimethylene terephthalate)(PTT) ternary system was determined by a high pressure apparatus based on a static method.The solubility of 1,3-PDO in SCCO2 and distribution coefficient of 1,3-PDO between the polymer and the supercritical fluid were also determined experimentally at 313.15 K to 353.15 K over the pressure range of 7 MPa to 19 MPa.Moreover,the effects of temperature and pressure were investigated in a detail.The results show that the solubility is 0.262-3.597 g/L,and the distribution coefficient is 0.020 5-0.076 2.The solubility increases with increasing pressure at a constant temperature.The change of solubility with temperature is complex,and there is a cross over pressure point(about 18 MPa).On either side of the pressure,the solubility shows the opposite trend.The distribution coefficient isotherms are inverted U shape with increasing pressure,and it means all of them increase first and then decrease.%溶质-超临界流体-聚合物三元体系相平衡的研究为超临界流体辅助聚合物脱挥技术提供了热力学基础数据,利用自行研制的一套超临界CO2高压装置,采用静态法,研究了温度为313.15-353.15 K、压力为7-19 MPa条件下,二氧化碳(CO2)/1,3-丙二醇(1,3-PDO)/聚对苯二甲酸丙二醇酯(PTT)三元体系相平衡时超临界流体相中的组成.实验测得PTT模拟样品中1,3-PDO在SCCO2中的溶解度,并计算得到了1,3-PDO在SCCO2相与PTT相间的分配系数,同时分析了温度和压力对溶解度、分配系数的影响.在上述条件下,1,3-PDO的溶解度为0.262-3.597g/L,分配系数为0.020 5-0.076 2.研究结果显示:当温度一定时,溶解度随压力的增大呈现增大的趋势;溶解度随温度的变化会存在一转变压力(约18 MPa),在转变压两侧,溶解度会呈现相反的变化趋势;分配系数等温线随压力的增大呈现倒U型,即先增大后减小.
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