| Chitosan, poly(acrylic acid-co-acrylamide) |
Spray coating followed by chemical cross-linking (N,N-methylene-bis-acrylamide-cross linker) |
40–70 g g−1 in distilled water |
Enhance water retention, controlled release of fertilizer |
24
|
| Chitosan |
Chemical cross-linking (genipin-cross linker) |
112–145% in distilled water |
Increased water uptake by the plant, controlled release of urea |
25
|
| Chitosan |
Chemical cross-linking (glyoxal-cross linker) |
— |
Slow release of agrochemicals (dicyandiamide/DCD) |
26
|
| Chitosan, polyvinyl alcohol, acrylamide, and acrylic acid |
Reverse suspension polymerization (chemical cross-linking) (glutaraldehyde and N,N-methylene-bis-acrylamide-cross linker) |
120–230 g g−1 in deionized water |
Enhance water absorption capacity of the soil, controlled fertilizer release |
27
|
| Chitosan |
Chemical cross-linking (EDTA–urea-cross linker) |
238–570 g g−1 in distilled water |
Water absorption, controlled release of urea and metal ions |
28
|
| Chitosan and high acetyl gellan gum (HAGG) |
Cross-linking via ionic bond formation |
219 g g−1 in pure water |
Water retention, controlled release of fertilizer |
29
|
| Chitosan, silk fibroin and gelatin |
Blended hydrogel (no intermolecular interaction) |
5.32 parts per hundred of polymer |
Slow release of urea |
30
|
| Chitosan–cellulose and acrylic acid |
Graft polymerization |
390 g g−1 in distilled water and 39.5 g g−1 in saline solution (0.9% NaCl) |
Increase water absorption capacity of soil |
31
|
| Controlled release of fertilizer |
| Chitosan and starch |
Inotropic gelation technique |
— |
Controlled release of agrochemicals |
32
|
| Chitosan, sodium alginate, and polyacrylamide |
Radiation-induced polymerization (gamma-radiations) |
397 g g−1 in distilled water (maximum absorption) |
Water retention, soil conditioning, increase plant growth |
33
|
| Chitosan, poly(acrylic acid-co-acrylamide (ground basalt for making composite) |
Graft free radical co-polymerization |
∼600 g g−1 at pH = 3 |
Soil conditioning enhances plant growth and pH-sensitive water absorption |
34
|
| Chitosan and polyvinyl alcohol |
Freeze thawing method |
58.3% in distilled water (with 6 wt% chitosan) |
Water retention, increased plant germination, and controlled release of fertilizer |
35
|
| Chitosan |
Graft polymerization and mild oxidation |
∼2500% in distilled water |
Water regulation, controlled urea release |
36
|
| Chitosan and starch |
Ionotropic gelation and neutralization |
143–235% in distilled water |
Water retention, bio-fertilizer |
37
|
| Chitosan |
Chemical cross-linking (citric acid-cross linker) |
1250 g g−1 in distilled water |
Water absorption |
38
|
| Chitosan |
Chemical cross-linking salicylaldehyde-cross linker) |
154% in distilled water |
Water absorption, controlled fertilizer release, enhanced plant growth |
39
|
| Chitosan, gelatin and PVA |
Chemical cross-linking |
10–12 times than its mass |
Controlled delivery of agrochemical (inulin), water absorption |
40
|
| Chitosan ad starch |
Chemical cross-linking (glycerol & citric acid-cross linker) |
— |
Biodegradable mulch for invasive plants increases plant growth |
41
|
| Chitosan and starch |
Ionotropic gelation |
120–162% in distilled water |
Controlled release of fertilizer, water absorption |
42
|
| Chitosan-co-polyacrylamide–TiO2
|
Chemical cross-linking (glutaraldehyde-cross linker) |
364.76% without TiO2 maximum swelling |
Soil conditioner, plant growth promoter |
43
|
| 66.45–100% in distilled water |
| Chitosan and starch |
Chemical cross-linking (citric acid-cross linker) |
∼120% (almost the same in distilled water, glucose solution, and urea) |
Increase water absorption capacity of soil |
44
|
