High-pressure vapor−liquid equilibria data for the binary system methyl methacrylate + carbon dioxide were measured using the static method. Experiments were carried out in the pressure range of (6 to 13) MPa and for temperatures of 323.15, 333.15, 343.15, and 353.15 K. Experimental results were correlated with the Peng−Robinson equation of state using conventional mixing rules with one interaction parameter.

Polydimethylsiloxane-block-polystyrene-block-polydimethylsiloxane (PDMS-b-PS-b-PDMS)was synthesized by the radical polymerization of styrene using a polydimethylsiloxane-based macroazoinitiator (PDMS MAI) in supercritical CO 2 . PDMS MAI was synthesized by reacting hydroxyterminated PDMS and 4,4 -azobis(4-cyanopentanoyl chloride) (ACPC) having a thermodegradable azo-linkage at room temperature. The polymerization of styrene initiated by PDMS MAI was investigated in a batch system using supercritical CO 2 as the reaction medium. PDMS MAI was found to behave as a polyazoinitiator for radical block copolymerization of styrene, but not as a surfactant. The response surface methodology was used to design the experiments. The parameters used were pressure, temperature, PDMS MAI concentration and reaction time. These parameters were investigated at three levels (−1, 0 and 1). The dependent variable was taken as the polymerization yield of styrene. PDMS MAI and PDMS-b-PSb-PDMS copolymers obtained were characterized by proton nuclear magnetic resonance and infrared spectroscopy. The number-and weight-average molecular weights of block copolymers were determined by gel permeation chromatography.