| 摘要 |
PURPOSE: An amphoteric crosslinked copolymer, which is used as a surfactant in soil flushing technology, is provided to separate hydrophobic contaminants sorbed to the saturated soil matrix without resorption of surfactant exhausted to soil particles. The particle size of this surfactant is about 30 to 120 nano meters and it has thus a large contact area to contaminants. This surfactant can be removed even with a small amount of calcium chloride because the surfactant is a crosslinked-structure, thus use of the amphoteric surfactant enables soil flushing technology not requiring additional facilities of recapturing operation for the exhausted surfactant. CONSTITUTION: The amphoteric crosslinked copolymer is prepared by reacting monomers having double bonds such as stylene, sodium salt of stylene sulfonate, divinylbenzene, methyl methacrylate and butyl acrylate with the urethane acrylate oligomer represented by the chemical formula 2. The abovementioned compounds are emulsified by phase inversion emulsification with initiator and polymerized at 70deg.C for about 5 hrs under stirring with the speed of 100 rpm. In the obtained copolymer represented as A-B-C-B-A, A represents compounds having double bonds and functional groups of hydroxy or amino, and it is one compound selected from the group consisting of hydroxy methacrylates and hydroxy acrylates; B represents compounds having two or more isocyanate groups which react with A to make urethane or urea, and it is one compound selected from the group consisting of toluene diisocyanate, isophorone diisocyanate and methylene diisocyanate; C is either one compound selected from polyols such as polytetramethylene glycol, polypropylene glycol or one compound selected from the group consisting of dimethylol propionic acid and methyl ethanol amine that have two hydroxy groups together with ionic groups, accordingly possible to make urethane or urea bonding with isocyanate.
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