Dissolved amounts of supercritical carbon dioxide in bamboo fiber/polypropylene composites with cosolvent

In order to assess the effect of cosolvent on the dissolved amounts of supercritical carbon dioxide (SCCO2) in bamboo fiber/polypropylene (BF/PP) composites, the dissolved amounts were measured at 313.15 K and pressures ranging from 15 to 25 MPa by a gravimetric method. The diffusion of mixed solvents out of BF/PP presented Fickian behavior and Fick’s diffusion model was applied to determine the dissolved amounts. The increase of dissolved amounts with the addition of ethanol can be explained not only by the density effect, but also by the specific interactions (especially hydrogen bonding) between the solute and cosolvent. The cosolvent effect reached a clear maximum at 20 MPa for both 2 % and 4 % ethanol, which seemed to be the result of specific interactions in concert with the difference between local and bulk density.