Syntheses and Characterization of Cephalexin-Chitosan/Natural Rubber network polymer for Slow-Release Fertilizer.

Abstract

The increase in the world's population has forced the agricultural sector to increase the production of crops to meet food needs. The spread of nutrient deficiencies in the soil led to economic losses, a reduction in nutritional quality, and total grain quantity for humans and livestock. Coating fertilizers with polymers is one of the most important and effective aspects of slow-release fertilizers in the soil. aim this study, the reaction between chitosan and expired cephalexin as a grafted polymer was done and vulcanized with natural rubber in the presence of tetra methyl thiuram disulfide as catalyst to cover the urea fertilizer. The grafted polymer (chitosan/expired cephalexin compound) was prepared by the Schiff base method. The expired medicinal compound of cephalexin is rich in carbon, nitrogen, sulfur, and hydrogen atoms which improved the diffusion of the fertilizer .So the reaction of the validity of the reaction between chitosan and expired Cephalexin was confirmed by infrared (IR) and it was confirmed the presence of new absorption band due to the Azomethine group. The swelling, water retention, slow release of urea, and biodegradation of the NR/chitosan/expired cephalexin compounds were characterized. The rheometer test was carried out under the pressure of 250 bar and temperature of 170°C, The results showed that the Slow release of urea was increased with the increase in the concentration of cephalexin. The highest release percentage in soil media was 2.67 g/l for the C2 blend. The highest swelling ratio was 189.49 % for the C4 blend while the highest water retention was 75.67% for the C2 blend. It was also shown a good biodegradability, where the highest concentration of cephalexin with chitosan gave the highest rate of biodegradation to be 14.61% for C4. The homogeneity of the blends was studied by FE-SEM. It was concluded that the C1-C4 blends were the best for slow-release fertilizer application.