Abstract
The adsorption of polyvinyl alcohol (PVA) on swelling clays was studied in its aqueous solution. The amounts of PVA adsorbed on swelling clays were measured by thermogravimetric and elementary analyses. The d (001) spacings of swelling clay minerals adsorbing PVA and containing water were measured by means of X-ray diffraction method. The amounts of PVA adsorbed on sodium montmorillonite, aluminum montmorillonite and synthetic mica were 0.53, 0.12 and 0.080g-PVA/g-Clay, respectively. The d (001) spacings of their clay minerals adsorbed PVA were 20.9, 15.0 and 13.9A, respectively. Because d (001) spacings of their clay minerals increased in proportion to the amount of PVA adsorbed, it was concluded that PVA adsorbed existed in the interlayer region.
The d (001) spacings of sodium montmorillonite and aluminum montmorillonite containing 2ml-Water/g-19Å Clay of water were measured. The spacings were 64Å for the former and for the latter. On the other hand, synthetic mica containing water swelled hardly. A strong dependence was observed between the amount of adsorbed PVA and the d (001) spacings of clay minerals swollen by water. Therefore, it was concluded that the amount of PVA adsorbed on swelling clays depended on the degree of swelling.
The amount of PVA adsorbed on saponite was 0.77g-PVA/g-Clay, which was the largest amount among the clays used in this study. This may be rationalized by the formation of card-house structure.
