Experimental cloud-point data of binary and ternary mixtures for poly(isobornyl methacrylate) [P(IBnMA), M-w = 100,000 and 550,000] in supercritical carbon dioxide, dimethyl ether (DME), propane, propylene, butane and 1-butene have been studied experimentally using a high pressure variable volume view cell. These systems show the phase behaviour over a temperature range from (323 to 466) K and pressure up to 276 MPa. The cloud-point curves for the {P(IBnMA) + CO2 + isobornyl methacrylate (IBnMA)} are measured in changes of the pressure-temperature (p, T) slope, and with co-solvent concentrations of (39.4 to 71.2) wt.%. P(IBnMA) does not dissolve in CO2 up to a temperature of 503 K and a pressure of 290 MPa. The location of the {P(IBnMA) + CO2} cloud-point curve shifts to lower temperatures and pressures when DME is added to the {P(IBnMA) + CO2} solution. The cloud-point curves of {P(IBnMA) (M-w = 100,000) + IBnMA and DME} in CO2 change from upper critical solution temperature behaviour to lower critical solution temperature behaviour as IBnMA and DME concentration increases. Also, experimental data of phase behaviour for IBnMA in supercritical carbon dioxide is performed at temperature range of (313.2 to 393.2) K and pressure range from (3.29 to 23.52) MPa. The experimental results were modelled with the Peng-Robinson equation of state using a van der Waals one-fluid mixing rule including two adjustable parameters. The pure critical property of IBnMA is estimated using the Joback-Lyderson method. (C) 2014 Elsevier Ltd. All rights reserved.