It possesses the feature that, absorption swelling it does concentration of the soil revised

摘要

PURPOSE: To provide a soil-improving material comprising a hydrophilic crosslinked polymer whose swollen volume is changed in response to the change in the concentration of an electrolyte, capable of preventing the accumulation of salt-containing underground water on the surface of the ground, and capable of rapidly allowing water flown in soil to permeate into the underground. ;CONSTITUTION: This material comprises a hydrophilic crosslinked polymer capable of swell-absorbing an electrolyte aqueous solution having a higher concentration than a critical salt concentration existing in a concentration range of 0.01-2wt.% (the polymer preferably exhibits an absorption ratio of ≥10 times for electrolyte aqueous solutions having concentrations of ≥1wt.% and also an absorption ratio of ≤25 times for the aqueous solutions having concentrations of ≤0.01wt.%), and does not swell in a lower concentration range. The polymer is preferably a polymer containing one or more of sulfobetaine type functional group-having vinylic monomers of formulas I-IV [R₁ is H, methyl; RCONSTITUTION is 0-6C (hydroxy)alkylene; R₃, R₄ are methyl, ethyl; R₅ is 1-10C (hydroxy)alkylene; R₆ is 1-6C (hydroxy)alkylene; X is ester, amide, (substituted)phenyl] as essential components.;COPYRIGHT: (C)1996,JPO