近年来,超临界二氧化碳(sc-CO2 ) 在聚合反应中的应用受到了越来越多的关注。本文主要综述了以sc-CO2 为反应介质的自由基聚合、阳离子聚合、过渡金属催化聚合、热致开环聚合、溶胶2凝胶聚合以及氧化耦合聚合的研究概况。一系列研究结果表明sc-CO2 是非常有前途的反应溶剂,在高分子合成领域将会有更加广阔的应用前景

A series of AOT (aerosol-OT) analogue surfactants (sodium salt of dibutyl-2-sulfosuccinate, sodium salt of dipentyl-2-sulfosuccinate, sodium salt of dihexyl-2-sulfosuccinate, and sodium salt of dioctyl-2-sulfosuccinate) were synthesized and characterized by 1H NMR and elemental analysis. A static method coupled with gravimetric analysis is developed to measure the solubility of the surfactants in 1,1,1,2-tetrafluoroethane (HFC-134a) and supercritical CO2 (scCO2). The solubilities of the surfactants in HFC-134a and scCO2 are affected by the temperature, pressure, and carbon atom number of the surfactant. The solubility of the same surfactant in HFC-134a solvent is approximately two times that in the most commonly used supercritical solvent CO2. The pressuretemperature phase diagrams for water/HFC-134a microemulsions stabilized by the surfactants were determined using cloud-point measurements for a concentration range of the surfactant from (1.85 _ 10-3 to 5.60 _ 10-3) M, temperature up to 338 K, and pressure up to 40 MPa in a high-pressure vessel. At a fixed temperature, the cloud-point pressure increased with increasing water-to-surfactant molar ratio (Wo). At a fixed Wo, the cloudpoint pressure decreased with increasing temperature. The surfactant with the longest hydrocarbon chain has the highest cloud-point pressure even at lower surfactant concentrations.

A series of fluorinated analogues of AOT, the sodium salt of bis(3,3,4,4,5,5,6,5,7,7,8,8,8-tridecafluorooctyl)-2-sulfosuccinate (CF3(CF2)5CH2CH2OOCCH2CH(SO3Na)COOCH2CH2(CF2)5CF3, di-HCF7),the sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentyl)-2-sulfosuccinate (H(CF2)4CH2OOCCH2CH-(SO3Na)COOCH2(CF2)4H, di-HCF4), and the sodium salt of bis(2,2,3,4,4,4-hexafluorobutyl)-2-sulfosuccinate(CF3CHFCF2CH2OOCCH2CH(SO3Na)COOCH2CF2CHFCF3, di-HCF3), were synthesized and characterized by 1HNMR. The pressure-temperature phase diagrams for W/CO2 microemulsions stabilized by the three surfactants were determined. At a fixed temperature, cloud point pressures increased with increasing water-to-surfactant ratio. The water solubilization capacity increased in the order di-HCF4 > di-HCF3 > di-HCF7.

A series of Aerosol-OT (AOT, sodium bis(2-ethylhexyl)sulfosuccinate) analogue fluorinated surfactants, i.e.,the sodium salt of bis(2,2,3,3,3-pentafluoropropyl) 2-sulfosuccinate (di-CF2), the sodium salt of bis(2,2,3,4,4,4-hexafluorobutyl)2-sulfosuccinate (di-HCF3), the sodium salt of bis(3,3,4,4,5,5,6,6,6-nonafluorohexyl)2-sulfosuccinate (di-HCF4), and the sodium salt of bis(2,2,3,3-tetrafluoropropyl) 2-sulfosuccinate (di-HCF2), were synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, melting point, and elemental analysis. The pressure-temperature (P-T) phase diagrams for water-in-CO2 (W/CO2) and water-in-1,1,1,2-tetrafluoroethane (W/HFC-134a) microemulsions stabilized by the surfactants were determined. In this work, the phase behaviors for different surfactants are obtained in supercritical CO2 (scCO2) and 1,1,1,2-tetrafluoroethane (HFC-134a) as a function of temperature, pressure, and water-to-surfactant ratio. At a fixed temperature, the cloud-point pressures increased with the increase of water-to-surfactant ratio (Wo) and the concentration of the surfactants. The cloud-point pressures for the surfactants in HFC-134a decrease with an increase in temperature at a fixed Wo and a surfactant concentration, which is in opposition to the results obtained in scCO2.

A series of novel fluorinated analogues of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) surfactants, the sodium salt of bis(3,3,4,4,5,5,6,6,6-nonafluoro-1-hexanol) sulfosuccinate (CF3(CF2)3CH2CH2OOCCH2CH(SO3Na)COOCH2CH2(CF2)3CF3, di-HCF5), the sodium salt of bis(2,2,3,4,4,4-hexafluoro-1-butanol) sulfosuccinate (CF3CFHCF2CH2OOCCH2CH(SO3Na) COOCH2CF2CFHCF3, di-HCF3), the sodium salt of bis(2,2,3,3- tetrafluoro-1-propanol) sulfosuccinate (HCF2CF2CH2OOCCH2CH(SO3Na)COOCH2CF2CF2H, di-HCF2), and the sodium salt of bis(2,2,3,3,3-pentafluoro-1-propanol) sulfosuccinate (CF3CF2CH2OOCCH2CH(SO3Na)COOCH2CF2CF3, di-CF2), were synthesized and characterized by 1H NMR, 13C NMR, 19F NMR and FT-IR spectroscopy, melting point, and elemental analysis. The pressure–temperature phase behavior for water-in-CO2 microemulsions stabilized by the four surfactants was tested and the P–T diagrams were determined. In the phase behavior experiments, pressures up to 35 MPa, temperatures up to 65 uC, and water-to-surfactant molar ratios (Wo) from 10 to 30 were tested. The cloud-point pressure in microemulsions stabilized by the four fluorinated surfactants increased with increasing temperature, and at a fixed temperature, the cloud-point pressure increased with increasing Wo. However, the cloud-point pressure was only slightly affected by an increase in the concentration of surfactant at a settled Wo. The phase behavior for water-in-CO2 microemulsions at different Cd(NO3)2 concentrations in the aqueous phase with the surfactant di-HCF5 was also determined, which is useful for the formation of CdS nanoparticles in our future studies.