Production of super-absorbed hydrogels prepared by electron beam irradiation for agricultural and industrial purposes

Polyacrylamide/sodium alginate (PAAm/Na-alginate) crosslinked super-absorbed hydrogels were prepared by using electron beam irradiation. The gel content and the swelling behavior of the obtained copolymers were investigated. The addition of PAAm/Na-alginate copolymer in small quantities to sandy soil increased its ability to retain water. The growth and other responses of the faba bean plant cultivated in a soil treated with PAAm and PAAm/Na-alginate copolymer were investigated. The growth of the bean plant cultivated in a soil containing PAAm/Na-alginate was better than that cultivated in soil treated with PAAm. The increase in faba bean plant performance by using PAAm/Na-alginate copolymer suggested its possible use in the agriculture field as a plant growth promoter. On the other hand, crosslinked polyacrylamide PAAm and acrylamide-Na- acrylate P(AAm-Na-AAc) super-absorbed microgels were prepared by electron beam irradiation. It was found that the dose required for crosslinking depends on the polymer moisture content, so that the dose to obtain PAAm of maximum gel fraction was over 40 and 20 kGy for dry and moist PAAm, respectively. The structural changes in irradiated PAAm were investigated using FTIR and SEM. The swelling property of such microgels in distilled water and real urine solution was determined and crosslinked polymers reached their equilibrium swelling state in a few minutes. The ability of the microgels to absorb and retain large amount of solutions suggested their possible uses in horticulture and in hygienic products such as disposable diapers. (author)