Syntheses and Characterization of Chitosan-Expired Amoxicillin/Natural Rubber Copolymers for Slow-Release Fertilizer

Abstract

As the global population rises, so does the urgency with which the agricultural sector must increase crop output to keep up with demand. The spread of nutrient deficiencies in the soil led to economic losses and a significant decrease in nutritional quality and total quantity of grains for humans and livestock. Fertilizers can increase nutrient use efficiency through the slow release mechanism and targeted or controlled delivery. Coating fertilizers with polymers is one of the most important and effective aspects of slow-release fertilizers in the soil. In this study, urea fertilizer was coated with a grafted polymer prepared from chitosan and expired amoxicillin using condensation reaction and vulcanized with natural rubber using tetramethyl thiuram disulfide (TMTD) as catalyst. The expired amoxicillin improved the diffusion of the fertilizer. The FTIR results confirmed the presence of azomethine group in chitosan/expired amoxicillin. The swelling, water retention, slow release of urea, biodegradation and remoter tests of the chitosan/NR/expired amoxicillin compounds were characterized. The slow release rate of urea was decreased with the increase in the concentration of amoxicillin. The highest release percentage in soil media was 2.69 g/L for the B2 blend. The highest swelling ratio was 189.482 % for the C4 blend while the highest water retention was 75.69% for the B2 blend. It was also shown a good biodegradability, where the highest concentration of amoxicillin with chitosan gave the highest rate of biodegradation to be 14.63% for C4. The homogeneity of the mixtures was studied by FE-SEM technique. It was concluded that the C1-4 blends were the best for slow-release fertilizer application.