Abstract: | The dilation of low-density polyethylene accompanied by the sorption of CO2 was measured by microscopy under pressures up to 50 atm at temperatures from 25 to 55°C. The dilatometry measurement, which is also applied to the determination of the thermal expansion coefficient, is directly performed by a cathetometer. The dilation of LDPE by sorbed CO2 is linear with concentration. The buoyancy correction is described for the CO2 sorption isotherms in LDPE. The partial molar volume of CO2 in LDPE, calculated from the dilation and the sorption isotherms, is almost independent of temperature. |