高分子と医薬品との相互作用(第6報) : 橋かけポリアクリル酸の水蒸気吸着による膨潤

抄録

Swelling of crosslinked polyacrylic acid (neutralization degree 0.9, mean polymerization degree between two adjacent crosslinks 4850) by water vapor was examined from polymer solution theory and introduction of swelling isotherm equation was attempted. Examinations were made on the adsorption isotherm equation of Rowen-Simha and swelling theory of Flory, et al., and some difference was observed between experimental results and theoretical values in the range of high relative vapor pressure. The modified equation formula obtaimed by application of the electrostatic interaction between counterion and polymeric ion derived by Voorn-Overbeck to Flory's swelling theory was found to satisfy the experimental results over a whole range of relative vapor pressure. Various differential thermodynamic functions obtained from the adsorption isotherm showed that the standard differential enthalpy of adsorption and standard differentical adsorption entropy are approximately equal to those for the condensation of water vapor to liquid water and there was found no special interatcion between crosslinked polyacrylic acid and water molecule.