Gels and hydrogels and seed

Abstract

Gels and gel-containing materials, including hydrogels, are described. A gel can be formed by blending polyacrylic acid (PAA) and a polyglycol, such as polytetramethylene ether glycol (PTMEG) at room temperature and, in some cases, without using a catalyst. The blend material can be used to form soft or hard materials, films and particles. The blend material can be combined with vinyl monomers and polymerize to form a hydrogel. The hydrogel can have a high mechanical strength and high water absorbency. The materials may coat a plant seed.

What is claimed is: 
     
         1 . A coated seed comprising:
 a plant seed; and   a coating of a hydrogel comprising:
 a first polymeric material having polyacrylic acid; 
 a second polymeric material comprising polytetramethylene ether glycol; and 
 one or more species having a vinyl functionality. 
   
     
     
         2 . The coated seed of  claim 1 , wherein at least one of the first polymeric material and the second polymeric material is substantially a homopolymer. 
     
     
         3 . The coated seed of  claim 1 , wherein at least one of said one or more species having a vinyl functionality is selected from the group consisting of: acrylamide, acrylic acid, methylacrylic acid, vinyl alcohol, vinyl acetate, butyl acrylate, vinyl acrylate, vinylbenzoic acid, vinylbenzyl alcohol, vinylboronic acid dibutyl ester, vinylformamide, vinyl methacrylate, vinylpyridine, 1-vinyl-2-pyrrolidone, vinylsulfonic acid, and vinyltrimethoxysilane. 
     
     
         4 . The coated seed of  claim 1 , wherein the hydrogel further comprises a cross-linker selected from the group consisting of: di(ethyleneglycol) divinyl ether, di(ethylglycol) diacrylate, and N,N′-methylene bis(acrylamide). 
     
     
         5 . The coated seed of  claim 1 , wherein at least one of said one or more species having a vinyl functionality is covalently bonded to the first polymeric material. 
     
     
         6 . The coated seed of  claim 1 , wherein the hydrogel has a water-retention capacity of at least about 10% of the weight of the hydrogel. 
     
     
         7 . The coated seed of  claim 1 , wherein the ratio, by weight, of the first polymeric material to the second polymeric material is between about 1-to-3, and about 1-to-6. 
     
     
         8 . The coated seed of  claim 1 , wherein the hydrogel further comprises one or more of: a cellulose, gelatin, clay, carboxymethyl cellulose, a fertilizer, silica, polyethylene and polystyrene. 
     
     
         9 . The coated seed of  claim 1 , wherein the hydrogel exhibits at least one of: a tensile strength of about 1000 g/cm 2  to about 4000 g/cm 2 , and an impact strength of about 1000 g/cm 2  to about 4000 g/cm 2 . 
     
     
         10 . The coated seed of  claim 1 , wherein at least one of: the Mw (g/mol) of the first polymeric material is from about 250,000 to about 1,000,000, and the Mw (g/mol) of the second polymeric material is from about 650 to about 2,000. 
     
     
         11 . The coated seed of  claim 1 , wherein the hydrogel has a water-retention capacity of at least about 20% of the weight of the hydrogel. 
     
     
         12 . The hydrogel of  claim 1 , wherein the hydrogel has a water-retention capacity of at least about 100% of the weight of the hydrogel. 
     
     
         13 . The hydrogel of  claim 1 , wherein the hydrogel has a water-retention capacity of at least about 10 times the weight of the hydrogel. 
     
     
         14 . The hydrogel of  claim 1 , wherein the hydrogel has a water-retention capacity of at least about 50 times the weight of the hydrogel. 
     
     
         15 . The coated seed of  claim 1 , wherein the plant seed comprises a seed configured to grow in an arid environment. 
     
     
         16 . A coated seed, comprising:
 a plant seed; and   a coating of a gel comprising:
 a first polymeric material having polyacrylic acid; and 
 a second polymeric material comprising polytetramethylene ether, 
   wherein the first polymeric material is hydrogen-bonded to the second polymeric material.   
     
     
         17 . The coated seed of  claim 16 , wherein at least one of the first polymeric material and the second polymeric material is substantially a homopolymer. 
     
     
         18 . The coated seed of  claim 16 , wherein the ratio, by weight, of the first polymeric material to the second polymeric material is between about 1-to-3, and about 1-to-6. 
     
     
         19 . The coated seed of  claim 16 , wherein the gel exhibits at least one of: a tensile strength of about 1000 g/cm 2  to about 4000 g/cm 2 , and an impact strength of about 1000 g/cm 2  to about 4000 g/cm 2 . 
     
     
         20 . The coated seed of  claim 16 , wherein at least one of: the Mw (g/mol) of the first polymeric material is from about 250,000 to about 1,000,000, and the Mw (g/mol) of the second polymeric material is from about 650 to about 2,000. 
     
     
         21 . The coated seed of  claim 16 , wherein the gel comprises a hydrogel having a water-retention capacity of at least about 10% of the weight of the hydrogel. 
     
     
         22 . The coated seed of  claim 16 , wherein the gel comprises a hydrogel, and the hydrogel further comprises one or more of: a cellulose, gelatin, clay, carboxymethyl cellulose, a fertilizer, silica, polyethylene and polystyrene. 
     
     
         23 . The coated seed of  claim 16 , wherein the gel comprises a hydrogel, and the hydrogel has a water-retention capacity of at least about 20% of the weight of the hydrogel. 
     
     
         24 . The coated seed of  claim 16 , wherein the gel comprises a hydrogel, and the hydrogel has a water-retention capacity of at least about 100% of the weight of the hydrogel. 
     
     
         25 . The coated seed of  claim 16 , wherein the gel comprises a hydrogel, and the hydrogel has a water-retention capacity of at least about 10 times the weight of the hydrogel. 
     
     
         26 . The coated seed of  claim 16 , wherein the gel comprises a hydrogel, and the hydrogel has a water-retention capacity of at least about 50 times the weight of the hydrogel. 
     
     
         27 . A coated seed, comprising:
 a plant seed; and   a coating of a three-dimensional gel formed from:
 a first polymeric material comprising polyacrylic acid; and 
 a second polymeric material comprising a polyglycol having —O(CH2) n - units, where n is a number greater than or equal to 3, 
   wherein the first polymeric material is hydrogen-bonded to the second polymeric material.   
     
     
         28 . The coated seed of  claim 27 , further comprising at least one of: one or more unsaturated monomer species having a vinyl functionality; and methacrylic acid.