Adsorption of Small Molecule into Polymers in Supercritical Carbon Dioxide

A study was undertaken in supercritical carbon dioxide to investigate the adsorption of several kinds of small molecules into three kinds of polymers, i.e., polyurethane, ethylene-vinyl acetate copolymer and low-density polyethylene. Change in appearance of the polymers was observed. The weight changes of these polymers after adsorption were monitored by a simple gravimetric method. The result indicated that LDPE had a low adsorption of small molecules while PU and EVA had a good ad-sorption of small molecules. The weight change of polymers after treatment in mass with time showed a dependence on the logarithm of time and the diffusion coefficient was about 10-7cm2/ s.