Phase behavior for the poly(alkyl methacrylate)+supercritical CO₂+DME mixture at high pressures

The phase behavior curves of binary and ternary system were measured for poly(alkyl methacrylate) in supercritical CO₂, as well as for the poly(alkyl methacrylate)+dimethyl ether (DME) (or 1-butene) in CO₂. The solubility curves are reported for the poly(alkyl methacrylate)+DME in supercritical CO₂ at temperature from (300 to 465) K and a pressure from (3.66 to 248) MPa. Also, The high-pressure static-type apparatus of cloud-point curve was tested by comparing the measured phase behavior data of the poly(methyl methacrylate) [PMMA]+CO₂+20.0 and 30.4 wt% methyl methacrylate (MMA) system with literature data of 10.4, 28.8 and 48.4 wt% MMA concentration. The phase behavior data for the poly(alkyl methacrylate)+CO₂+DME mixture were measured in changes of the pressure-temperature (p, T) slope and with DME concentrations. Also, the cloud-point pressure for the poly(alkyl methacrylate)+1- butene solution containing supercritical CO₂ shows from upper critical solution temperature (UCST) region to lower critical solution temperature (LCST) region at concentration range from (0.0 to 95) wt% 1-butene at below 455 K and at below 245MPa.