全氟聚醚碳酸铵在超临界二氧化碳中的浊点

Cloud Points of Ammonium Carboxylates of Perfluoroether in Supercritical Carbon Dioxide

用体积可变的高压可视装置测定了全氟聚醚碳酸铵在超临界二氧化碳中的浊点行为．温度在308．15～333．15K的范围内，全氟聚醚碳酸铵完全溶解在二氧化碳中所需的最小压力不高于20．91MPa．分别作出了浊点压力随温度以及全氟聚醚碳酸铵与二氧化碳的质量比变化的关系曲线．一定浓度下的浊点压力随温度的升高而增大，呈现出典型的低临界会溶温度相行为．一定温度下的浊点压力与浊点密度的变化范围都很小，并且均随浓度的增大先上升，到达某一浓度后变为恒定值。

Experimental cloud points were determined using a variable-volume view cell apparatus for the ammonium Carboxylates of Perfluoroether （ PFPE-NH4 ） in supercritical carbon dioxide. Over the temperature range of 308. 15 to 333.15 K, the PFPE-NH4 was soluble in scCO2 at pressures no more than 20, 91 MPa. The curves were measured to study the effects of temperatures and mass ratios of PFPE-NH4/CO2 on the cloud point pressures and densities. The eloud point pressure at a fixed mass ratio increased with temperatures and exhibited what are known as lower critical solution temperatures （LCST）. At a fixed temperature, the cloud point pressures and densities increased with mass ratios at first, and became stable when the mass ratios exceeded some special value. Both the cloud point pressures and densities varied in some limited range at a fixed temperature.