Experimental Measurements and Modeling of Solubility and Diffusivity of CO2 in Polypropylene/Micro- and Nanocalcium Carbonate Composites

Abstract

The effects of the filler size and concentration on the solubility and diffusivity of CO2 in polypropylene (PP)/calcium carbonate (CaCO3) composites were investigated in this work. The apparent solubility of CO2 in PP and its composites containing 5 wt % and 10 wt % micro- or nano-CaCO3 was measured by using a magnetic suspension balance (MSB) at temperatures of 200 and 220 °C and CO2 pressures up to 22 MPa. Meanwhile, the swelling volume of the PP composites/CO2 solutions was experimentally measured at the same conditions by using a high-pressure view cell with direct visual observation. It was then used to correct the gas buoyancy acting on the PP composites in the MSB measurement so that the real solubility of CO2 in the PP composites was determined. Meanwhile, the diffusion coefficient of CO2 in the PP composites was estimated from the sorption lines at gas pressures ranged from 5 to 10 MPa. It was found that the experimental solubility and diffusivity of CO2 in PP/nano-CaCO3 composites were higher th...