This paper presents an overview of the chemical analyses of the Clay Mineral Society Source Clays based on X-ray Photoelectron Spectroscopy. This technique does not require any detailed sample preparation and is therefore easy to perform. In contrast to other common chemical analytical techniques fluorine and chlorine can be analysed together with all the major elements. In addition, the high resolution spectra reveal some details about the local environment of different cations in the clay structure, such as the presence of water, distinction between octahedral and tetrahedral aluminium and the presence of two types of Mg in the octahedral sheets.

We report the development of a new gas permeation measuring device based on the differential-pressure method, using a quadrupole mass spectrometer (QMS) that includes an in-situ calibration system. The device was applied to evaluating the high gas barrier property of clay-polymer nanocomposite films. The developed device has a detection limit in gas transmission rate (GTR) comparable or lower than those of other reported methods, when the difference of the sample area is taken into consideration. The gas barrier property of two clay-polymer nanocomposite films (SN and H2B) for H₂, He, and O₂ was evaluated using this device. A polyimide film (PI) was also measured for comparison. The GTR of SN film for H₂ and He at 31°C was 1.2 and 3.1 cm³ (STP) m⁻² day⁻¹ atm⁻¹, respectively, which were less than 1/1000 those of PI. The GTR of H2B was 0.43 cm³ (STP) m⁻² day⁻¹ atm⁻¹ for He, which was about 1/10 of the SN film. The GTR of H2B for H₂ could not be measured because it was below the detection limit (0.1 cm³ (STP) m⁻² day⁻¹ atm⁻¹). Similarly, the GTR of SN and H2B for O₂ could not be measured because it was below the detection limit (0.007 cm³ (STP) m⁻² day⁻¹ atm⁻¹). The temperature dependence of GTR was also evaluated. The diffusion coefficient and the solubility were calculated from the GTR. From the calculated results, we discussed the relationship between the structure, the type of binder and the gas barrier properties of clay-polymer nanocomposite films.

New nanocomposite hydrogels were synthesized by photopolymerization of mixtures containing clay mineral, N-isopropylacrylamide, and sodium acrylate with or without tetrasodium pyrophosphate as a dispersant. Addition of the dispersant was effective for gelating the mother mixture containing sodium acrylate. The stability and swelling behaviors of the obtained nanocomposites were investigated in deionized water at 25, 40, 50 and 60°C. Water absorbability of the nanocomposites increased with increasing content of sodium acrylate but hydrogels with high sodium acrylate content were unstable in hot water. The swelling kinetics were analyzed by a pseudo-second order rate equation.