Polymer modification using difluoromethane (HFC 32) and carbon dioxide

Abstract

The infusion of difluoromethane (HFC 32) and CO2 into polystyrene and polyethylene has been characterized using a quartz crystal microbalance technique over a range of temperatures and pressures. The results were adequately modeled by Flory‐Huggins theory. Significant plasticization was observed in the polymeric materials and it is shown that manipulation of the experimental temperature, pressure, and rate of depressurisation can cause significant changes in the morphology of the samples. It is demonstrated for the first time how rate constant data for the kinetics of gas sorption can be extracted quickly and easily from in situ quartz crystal microbalance measurements. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1072–1083, 2006

The Method on Modifying the Dynamic Properties of Self-Interactive Systems by External Factors

“…The motivation of this work is that we need to deal with the process which has the influence not only from itself, i.e., self-interacting, but also from other influences which are exogenous. As a matter of fact, from the viewpoint of chemical engineering, there are more and more needs to modify the property of polymer ( [5][6][7][8]), the consideration of the dynamic behavior ( [11][12][13][14]), and so on. The modification of self-interactive system is such a kind of problems.…”

Sugar Acetates as CO2-philes: Molecular Interactions and Structure Aspects from Absorption Measurement Using Quartz Crystal Microbalance

“…Several researchers have studied the behavior of adsorption/absorption of high pressure CO 2 on/into solid films using a QCM system. The solubility of CO 2 in a variety of polymers (i.e., polycarbonate, polystyrene, , polymethyl methacrylate) coated on the QCM crystal surfaces at high pressures have been reported. Other compounds such as proteins, polysaccharides, and some complexes have also been tested.…”

Acetone Influence on Glass Transition of Poly(methyl methacrylate) and Polystyrene in Compressed Carbon Dioxide

“…[3][4][5][6][7][8][9][10][11][12][13][14] In recent years, some new approaches have been used and the influence of pure carbon dioxide on the thermal properties of some copolymers or biopolymers were studied. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] In compressed or supercritical carbon dioxide, the glass transition temperature and the melting point of some polymers were obviously depressed. After CO 2 treatment, the crystallization for some semicrystalline polymers increased.…”

“…Due to its special characteristic properties, supercritical and subcritical carbon dioxide have been widely used as clean alternatives for conventional organic solvents in modifying and processing polymers. , Although most polymers have very limited solubility in carbon dioxide (CO 2 ), CO 2 has appreciable solubility in many polymers and can swell the polymer matrix at high pressure. Thus many studies have been done to investigate the influence of carbon dioxide on the structures and properties of the polymer matrix, especially the depression on glass transition temperature and melting point of polymers by pure carbon dioxide. − In recent years, some new approaches have been used and the influence of pure carbon dioxide on the thermal properties of some copolymers or biopolymers were studied. − In compressed or supercritical carbon dioxide, the glass transition temperature and the melting point of some polymers were obviously depressed. After CO 2 treatment, the crystallization for some semicrystalline polymers increased.…”