Glass transitions of polymers with compressed fluid diluents: type II and III behavior

Glass Transition Temperature of Polystyrene with Compressed Carbon Dioxide.

“…Hence information on Tg of PS has been given from the possible drawing of films under some pressure and temperature conditions [9]; it is suggested that Tg of PS in CO2 above 10MPa is lower than 308.2K. This idea is consistent with the results obtained by Condo et al from the creep compliance method [6].…”

“…The plasticization of polymers by compressed gases has been deduced from several techniques such as creep compliance, gas solubility, DSC, NMR relaxation times, and others. A few experimental studies have been so far reported on the gas-induced plasticization of polystyrene (PS) [4][5][6][7]. Previous studies on the Tg determination of PS have utilized the creep compliance method [4][5][6] and DSC method [7].…”

“…A few experimental studies have been so far reported on the gas-induced plasticization of polystyrene (PS) [4][5][6][7]. Previous studies on the Tg determination of PS have utilized the creep compliance method [4][5][6] and DSC method [7]. From their results, it has been clarified that the Tg was significantly depressed below the experimental temperatures at moderate CO2 pressures.…”

Propagation Rate Coefficients of Styrene and Methyl Methacrylate in Supercritical CO2

“…1,6 Some early kinetic studies on the γ-radiation-induced precipitation polymerization of ethylene in liquid carbon dioxide 5 showed that there were no large effects on the propagation rate as compared to bulk polymerizations. In heterogeneous polymerization in the presence of CO 2 , the large plasticization effects have a dramatic effect on diffusivities 7,8 and hence termination rate coefficients.In order to understand dispersion polymerizations in CO 2 , 1 as well as the effect of CO 2 in emulsion polymerizations in hybrid CO 2 /aqueous media, the monomer partitioning needs to be determined. In the case of the hybrid system, it is very hard to determine the monomer concentrations in polymer particles under pressurized conditions.…”

“…1,6 Some early kinetic studies on the γ-radiation-induced precipitation polymerization of ethylene in liquid carbon dioxide 5 showed that there were no large effects on the propagation rate as compared to bulk polymerizations. In heterogeneous polymerization in the presence of CO 2 , the large plasticization effects have a dramatic effect on diffusivities 7,8 and hence termination rate coefficients.…”