Identification of alternative solvents for processing of cellulosic polymers is of interest in a number of industrial applications, ranging from fibers to films. In this study, miscibility of cellulose acetate, cellulose triacetate, cellulose acetate butyrate, cellulose propionate and ethyl cellulose in ＇carbon dioxide + acetone＇ and ＇carbon dioxide + ethanol＇ binary fluid mixtures have been investigated. Data are reported at 3% by mass polymer concentration in two binary solvent fluid mixtures containing 30% and 70% by mass carbon dioxide. Demixing pressures are reported in the temperature range from 60 to 175 degrees C. Complete miscibility of the polymers was achieved at all pressures in carbon dioxide + ethanol mixtures containing 30% carbon dioxide, while in mixture containing 70% carbon dioxide, miscibility required pressures greater than 20 MPa. Higher pressures were required for miscibility in carbon dioxide + acetone mixtures with pressures being greater than 5 MPa and greater than 35 MPa for mixtures containing 30 and 70% carbon dioxide, respectively. The solutions all displayed LCST (lower critical solution temperature) behavior, with demising pressures increasing with temperature. The relative ease of miscibility of the polymers followed essentially the same order in either the ethanol or acetone fluid mixtures, with demixing pressures increasing as ethyl cellulose

Keywords:PRESSURE