Cloud-point data are reported for poly(isopropyl acrylate) [P(IPA)] in CO2, propane, propylene, butane, I-butene, and dimethyl ether (DME) and for poly(isopropyl methacrylate) [P(IPMA)] in CO2- P(IPA) + alkene cloud-point curves are similar to 100 degrees C lower than the P(IPA) +alkane curves, which are close to the P(IPA) + CO2 curve located at temperatures greater than 130 degrees C and pressures of 2500 bar. P(IPA) dissolves in pure DME at conditions as mild as 50 degrees C and 200 bar. Since IPA and IPMA monomers are used as cosolvents with CO2, binary IPA + CO2 and IPMA + CO2 data are reported to complement the ternary cloud-point data. Both monomer + CO2 mixtures exhibit type-l behavior and both are adequately modeled with the Peng-Robinson equation of state. IPMA is a more effective cosolvent than IPA. The polymer+ CO2 + monomer phase behavior suggests that it is viable to polymerize IPA or IPMA in CO2 at moderate operating conditions. (C) 2006 Elsevier B.V. All rights reserved.