Poly N-isopropyl acrylamide-sodium alginate double-layer coated temperature-sensitive slow-release nitrogen fertilizer and method for preparing same

Abstract

The invention discloses a poly N-isopropyl acrylamide-sodium alginate double-layer coated temperature-sensitive slow-release nitrogen fertilizer. A method for preparing the poly N-isopropyl acrylamide-sodium alginate double-layer coated temperature-sensitive slow-release nitrogen fertilizer includes carrying out oxidation treatment on sodium alginate by the aid of sodium periodate to obtain oxidized sodium alginate; coating urea with the oxidized sodium alginate to obtain sodium alginate coated urea micro-spheres; synthesizing temperature-sensitive polymer poly N-isopropyl acrylamide microgel;carrying out fluidized bed spray granulation on the temperature-sensitive polymer poly N-isopropyl acrylamide microgel to obtain the poly N-isopropyl acrylamide-sodium alginate double-layer coated temperature-sensitive slow-release nitrogen fertilizer. The sodium periodate is used as an oxidizing agent. The oxidized sodium alginate is used as a base material. The temperature-sensitive polymer poly N-isopropyl acrylamide microgel is used as a temperature-sensitive envelope material. The poly N-isopropyl acrylamide-sodium alginate double-layer coated temperature-sensitive slow-release nitrogenfertilizer and the method have the advantages that temperature-sensitive polymers are led into the surfaces of the sodium alginate coated urea micro-spheres, accordingly, double-layer slow-release coating can be carried out on nitrogen fertilizers, effects of retaining the poly N-isopropyl acrylamide-sodium alginate double-layer coated temperature-sensitive slow-release nitrogen fertilizer can berealized, and loss and wastage of fertilizers can be reduced; aldehyde sodium alginate can be degraded without special conditions with specific enzymes and the like, and accordingly the problem of secondary pollution can be solved.

Description

technical field [0001] The invention relates to the field of slow-release fertilizers, in particular to a poly-N-isopropylacrylamide-sodium alginate double-layer coated temperature-sensitive slow-release nitrogen fertilizer and a preparation method thereof. Background technique [0002] Coated controlled-release fertilizers are currently the main controlled-release fertilizer varieties. They mainly use granular chemical fertilizers as the core, and the surface layer is coated with a layer of low water-soluble inorganic substances or organic polymers to change the dissolution of fertilizer nutrients and prolong or control fertilizer nutrients. freed. However, the existing coated controlled-release fertilizers have the disadvantages of high cost, difficult degradation of coating materials, and secondary pollution when applied to the soil. Therefore, it is necessary to look for efficient, cheap and environmentally friendly coating materials to develop coated controlled-release ...

AI Technical Summary

Problems solved by technology

Sodium alginate can undergo ion exchange reaction with divalent metal ions except magnesium and mercury to form alginate hydrogel, but the degradation products of ion-crosslinked SA gel have a higher relative molecular mass, and the divalent positive ions It is easy to lose, so the degradation of the gel is not easy to control, and its aldehyde products are easier to degrade