Anionic polymers composed of dicarboxylic acids and uses thereof

Abstract

Biodegradable anionic polymers are disclosed which include recurring polymeric subunits preferably made up of dicarboxylic monomers such as maleic anhydride, itaconic anhydride or citraconic anhydride. Free radical polymerization is used in the synthesis of the polymers. The polymers may be complexed with ions and/or mixed with fertilizers or seeds to yield agriculturally useful compositions. The preferred products of the invention may be applied foliarly or to the earth adjacent growing plants in order to enhance nutrient uptake by the plants.

We claim:  
     
         1 . A method of decreasing nitrogen volatilization comprising the step of coating a fertilizer product with a polymer to form a coated fertilizer product.  
     
     
         2 . The method of  claim 1 , said fertilizer being selected from the group consisting of phosphate-based fertilizers; fertilizers containing nitrogen, phosphorous, potassium, calcium, magnesium, sulfur, boron, zinc, manganese, copper or molybdenum materials; and fertilizers containing micronutrients, and oxides, sulfates, chlorides, and chelates of such micronutrients.  
     
     
         3 . The method of  claim 1 , said polymer being 100% saturated with calcium.  
     
     
         4 . The method of  claim 1 , said polymer being 50% saturated with hydrogen and 50% saturated with calcium.  
     
     
         5 . The method of  claim 1 , said polymer including the salt form thereof.  
     
     
         6 . The method of  claim 1 , said polymer coating comprising at least about 0.005% by weight of said coated fertilizer product.  
     
     
         7 . The method of  claim 1 , said polymer coating comprising at least about 0.01% by weight of said coated fertilizer product.  
     
     
         8 . The method of  claim 1 , said polymer coating comprising at least about 0.5% by weight of said coated fertilizer product.  
     
     
         9 . The method of  claim 1 , said polymer comprising recurring polymeric subunits each made up of at least two different moieties individually and respectively taken from the group consisting of B, and C moieties, or recurring C moieties, where moiety B is of the general formula  
       
         
           
           
               
               
           
         
       
       and moiety C is of the general formula  
       
         
           
           
               
               
           
         
       
       wherein each R 7  is individually and respectively selected from the group consisting of H, OH, C 1 -C 30  straight, branched chain and cyclic alkyl or aryl groups, C 1 -C 30  straight, branched chain and cyclic alkyl or aryl formate (C 0 ), acetate (C 1 ), propionate (C 2 ), butyrate (C 3 ), etc. up to C 30  based ester groups, R′CO 2  groups, OR′ groups and COOX groups, wherein R′ is selected from the group consisting of C 1 -C 30  straight, branched chain and cyclic alkyl or aryl groups and X is selected from the group consisting of H, the alkali metals, NH 4  and the C 1 -C 4  alkyl ammonium groups, R 3  and R 4  are individually and respectively selected from the group consisting of H, C 1 -C 30  straight, branched chain and cyclic alkyl or aryl groups, R 5 , R 6 , R 10  and R 11  are individually and respectively selected from the group consisting of H, the alkali metals, NH 4  and the C 1 -C 4  alkyl ammonium groups, Y is selected from the group consisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V and Ca, and R 8  and R 9  are individually and respectively selected from the group consisting of nothing (i.e., the groups are non-existent), CH 2 , C 2 H 4 , and C 3 H 6 , each of said moieties having or being modified to have a total of two COO groups therein.