たばこ刻みの細孔分布測定のための脱水条件の検討

Abstract

Methods of preparation for the measurement of the distribution of pore sizes of tobacco were examined. We expected that drying at the critical point of samples before measurement of the N2 adsorption isotherm would prevent pore contraction. First, the material was soaked in ethanol, which displaced water in the pores, and then the ethanol was replaced with liquid CO2. However, this procedure resulted in swelling, contraction, or both; the changes depended on the concentration of the ethanol used to start the displacement. Therefore, a suitable concentration of ethanol was searched for. The amount of adsorbed water was calculated from the pore-size distribution to check the reproducibility of the effects of the preparation method. The values calculated for samples that were dehydrated with 40, 60, or 40 and 60% (w/w) of ethanol in water were in good agreement with the experimental data. Scanning electron micrographs showed that the shape of the samples had changed little compared with untreated samples. We concluded that the range of 40 to 60% (w/w) was the optimum concentration at which to start the displacement of water.