[1] Hydrogels are hydrophilic crosslinked polymers that form three-dimensional molecular networks which can absorb and hold great amounts of water.
[9] For example, a hydrogel based on gum tragacanth increases the water content of clay soil by up to 5.35% and of sandy loam by up to 5.5%; it could also be used to release calcium chloride slowly over a prolonged period.
Hydrogels developed for this purpose include polymers of oligooxyethylene methacrylate, linked by ionic and covalent bonds to a herbicide such as 4-chloro-2-methylphenoxyacetic acid (CMPA).
A polymer/clay superabsorbent composite material made by attaching acrylamide to finely powdered attapulgite (a fuller's earth clay) shows promise for its excellent water retention and low cost compared to polyacrylamide hydrogel.
the product is to be commercialized by the Ministry of Science and Technology's National Research Development Corporation (NRDC) in collaboration with a company based in Chennai, Reliance Industries Limited.