| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 201939 | Fluid Phase Equilibria | 2012 | 8 Pages |
Three different supercritical fluids, CO2, dimethyl ether (DME), and chlorodifluoromethane (CHClF2), were investigated as potential solvents for processing two (meth)acrylate polymers. High pressure phase behavior data to 505 K and 265.7 MPa were reported for poly(hydroxypropyl methacrylate) [PHPMA] and poly(hydroxypropyl acrylate) [PHPA] in the supercritical fluid solvents + cosolvent system. Cloud-point curves for the PHPA and PHPMA in the supercritical DME show about a 40.0 MPa pressure difference of constant temperature at ∼373 K. The phase behavior for the PHPMA + DME + 2-hydroxypropyl methacrylate (2-HPMA) and PHPA + DME + 2-hydroxypropyl acrylate (2-HPA) systems were measured from changes of the pressure–temperature curve slope, and with cosolvent concentrations of w3 = 0–0.463 (2-HPMA) and w3 = 0–0.453 (2-HPA), respectively. The PHPMA + DME + w3 = 0.0–0.238 CO2 and PHPA + DME + w3 = 0.0–0.210 CO2 mixture show UCST-type behavior with a negative slope, and then the pressure increases smoothly for temperatures in the range of 323–492 K. PHPMA and PHPA do not dissolve in pure CO2 at a temperature of 518 K and pressure of 280.0 MPa. The location of the PHPMA + CO2 cloud-point curve shifts to lower temperatures and pressures when w3 = 0.40–0.66 2-HPMA was added to the PHPMA + CO2 solution. The phase behavior for the PHPA + CO2 + w3 = 0.35–0.68 2-HPA system changes the pressure–temperature curve from an upper critical solution temperature (UCST) region to a lower critical solution temperature (LCST) region as the 2-HPA concentration increases. The PHPMA + CO2 + w3 = 0.689 2-HPMA phase behavior curve intersects a fluid → liquid + vapor (LV) curve at ∼393 K and ∼16.0 MPa.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Cloud-point behavior for the P[HP(M)A] + supercritical solvents + cosolvents mixtures were measured. ► Measurements were performed using static type at temperature range from 315 K to 505 K and pressure up to 265.7 MPa. ► Phase behavior for the P[HP(M)A] + DME + 2-HP(M)A systems intersect the fluid → vapor + liquid curves.
