Self-situating stimuli-responsive polymer compositions in soil additives and methods for use
AssigneeRhodia Operations
InventorsZhiyun Chen, Jean-Christophe Castaing, Marie-Pierre Labeau, Gilda Lizarraga
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AssigneeRhodia Operations
InventorsZhiyun Chen, Jean-Christophe Castaing, Marie-Pierre Labeau, Gilda Lizarraga
Estimating the term…
Disclosed are soil additives comprised of self-situating, stimuli-responsive polymer compositions and methods of their use. In one embodiment, the polymer composition or polymer network comprises permanent cross-links and non-permanent cross-links, wherein the non-permanent cross-links are capable of being removed upon application or exposure to a stimulus, typically located within the soil. In another embodiment, the method of increasing water retention in soils includes applying a soil additive, comprising polymer networks of the present invention admixed with an aqueous solution to form a colloidal dispersion solution or suspension, to a soil surface. The suspension or colloidal dispersion solution facilitates penetration of the polymer composition through the soil surface and into the soil, migrating typically to lower water potential areas and, more typically, along drainage channels located within the soil. After penetration of the soil surface, the polymer network is then exposed to a stimulus, typically present in the soil, whereby the non-permanent cross-links are removed and the polymer composition undergoes a volumetric change. This results in the prevention, arrest or decelerated loss of water from the targeted area, for example the plant root zone, which allows for improved water usage efficiency by plants, grasses, vegetation, etc.
A soil additive comprising particles having a first polymer structure having a mean particle diameter (D50) of from about 0.1 micrometers to about 200 micrometers, the first structure comprising permanent cross-links and non-permanent ionic cross-links, the particles having a property such that only upon contact with a monovalent stimulus selected from the group consisting of sodium ions, potassium ion, ammonium ions and any combination thereof present in soil, the non-permanent ionic cross-links become at least partially removed from the first structure via ion exchange with the monovalent stimulus, resulting in a second structure having a D50 of from about 1 micrometer to about 5000 micrometers and a volume greater than the first structure, the ratio of volume of the first structure to the second structure being from about 1:3 to 1:500, wherein the ionic cross-links are derived from a cation selected from the group consisting of calcium, magnesium, zinc, copper, ferrous, barium, and any combination thereof.
A method of increasing water retention in soil comprising applying a soil additive to soil, the soil additive comprising particles having a first polymer structure having a mean particle diameter (D50) of from about 0.1 micrometers to about 200 micrometers, the first structure comprising permanent cross-links and non-permanent ionic cross-links, the particles having a property such that only upon contact with a monovalent stimulus selected from the group consisting of sodium ions, potassium ions, ammonium ions, and any combination thereof present in soil, the non-permanent ionic cross-links become at least partially removed from the first structure via ion exchange with the monovalent stimulus, resulting in a second structure having a D50 of from about 1 micrometer to about 5000 micrometers and a volume greater than the first structure, the ratio of the volume of the first structure to the second structure being from about 1:3 to 1:500, wherein the ionic cross-links are derived from a cation selected from the group consisting of calcium, magnesium, zinc, copper, ferrous, barium, and any combination thereof.
Dependencies are inferred from the claim text.