Jiaqiu Wang

Study on the phase behavior of cholesterol-acetone-CO2 system and recrystallization of cholesterol by antisolvent CO2

Abstract The composition of the liquid phase of cholesterol–acetone–CO 2 system was determined at 308.15 and 318.15 K in the pressure range from 0.1 to 7.5 MPa. The solubility of cholesterol in the acetone–CO 2 mixture decreases with increasing pressure and increases with temperature. Recrystallization of cholesterol was performed in acetone solution by using CO 2 as an antisolvent. The size of the particles obtained at different conditions was examined by scanning electron microscopy (SEM).

Synthesis of composites of silicon rubber and polystyrene using supercritical CO2 as a swelling agent

The heterogeneous free-radical polymerization of styrene within supercritical carbon dioxide swollen silicon rubber film has been conducted to prepare the silicon rubber/polystyrene (SR/PS) polymer blends. The PS content in the blends can be controlled by adjusting the soaking time and the concentration of styrene in the supercritical fluid. Scanning electron microscopy (SEM) indicates that the PS phase is uniformly distributed in the blends and the phase size is very small (100 nm to 300 nm), although the two polymers are very different and incompatible. The mechanical properties of the blends and the average molecular weight of the PS polymerized in the matrix were also measured. The results indicate that the average molecular weight of the PS in the blend depends on the PS content or its phase size. The tensile strength of the blends is higher than that of original SR substrate, and there is a maximum in tensile strength vs. PS content. The Youngs modulus of the blends increases monotonously with PS content in the blends.