Abstract
We found the phenomenon that insolubilized polymer accumulated as an impermeable layer in a soil, when an aqueous solution of the polymer with carboxyl groups such as polyacrylic acid percolated into the soil. We conducted the layer formation in a soil column with various compositions of the polymer solution, and studied the effects of the preparation condition of polymer solution on the formative phenomenon of the impermeable layer. The results are as follows.1. An impermeable layer was formed deeper in a soil as the polymer concentration of the solution decreased or the neutralization ratio of the carboxyl groups of the polymer increased. We can use these results to control the depth of the impermeable layer in a soil from soil surface to 100cm.2. The amount of the polymer solution needed to form an impermeable layer increased as the polymer concentration decreased or the neutralization ratio of the carboxyl groups increased. The amount of the polymer solution varied in proportion to the depth of the impermeable layer in a soil.3. It was suggested that 0.7-1.0 kg m^<-2> of the polymer in the solution reached to the depth of the impermeable layer and 0.3 kg m^<-2> of the polymer became the element of the impermeable layer.4. Addition of salts to the polymer solution made the impermeable layer form at a more shallow level in a soil.5. Polyacrylic acid with an average molecular weight over 100,000 was able to form the impermeable layer in a soil, but that with an average molecular weight below 20,000 was not able to form it.
