Radiation synthesis of urea/hydrogel core shells
A new study describes urea/hydrogel core shells coated with three different natural oils via a layer-by-layer approach and presents an investigation of their slow release and effects on plant growth-promoting rhizobacteria.
During the study, single and double-coated water-retention urea fertilisers were prepared by crosslinking urea with poly acrylonitrile (PAN) alone and with PAN-based poly acrylic acid (PAAc) hydrogels, respectively.
In the first synthesis, the urea granules (the core) were coated with three different natural oils, namely epoxidised soybean oil (ESO), oleic acid (OA), and linseed oil (LO), to form the first shell. The second shell was formed with PAN and PAN-based PAAc hydrogels, as the two categories. The polymerisation reaction was performed, employing various doses of gamma (γ)-ray irradiation. Further, the effect of the various doses of γ irradiation on the slow-release property of urea was examined in water. The results indicated that the two kinds of polymers had regulated the release of urea. Additionally, the water-retention properties of the coated urea were also studied.
Safer for utilisation in agricultural fields
As observed, the slow-release property of urea−PAN was better than that of urea–PAAc/PAN in all the three samples. The results further indicated that urea–PAAc/PAN exhibited good urea slow-release property and also possessed excellent water-holding capacity, which could exert better effects on fertiliser and water supplies. Additionally, the in vitro antibacterial activity of the urea granule coatings with hydrogel against plant growth-promoting rhizobacteria (PGPR) was investigated. The in vitro antibacterial potential demonstrated that there was no zone of inhibition (ZOI) around the tested samples of urea–PAN and urea–PAAc/PAN.
This indicated that the synthesised urea granule coatings with hydrogel exhibited no antagonistic effect on PGPR and was, therefore, safer for utilisation in agricultural fields.
The study has been published in Progress in Organic Coatings, Volume 151, February 2021.
