Incorporation of Urea Fertilizer and Activated Carbon in Carboxymethyl Cellulose-Based Bioplastics

The high mobility of urea as a nitrogen nutrient in the soil leads to inefficient absorption by plants. Hence efforts to design a slow-release fertilizer (SRF) are significant. This paper reports the incorporation of urea fertilizer with carbon or zeolite in a bioplastic made of carboxymethyl cellulose as the matrix. The bioplastics were made by mixing the zeolite or activated carbon suspensions into a sodium carboxymethyl cellulose (Na-CMC) gel. Glycerol was then added as a plasticizer. Six variations of bioplastics were prepared, namely CMC-urea 0.5 and 1.0, CMC-urea-zeolite, CMC-urea-zeolite-glycerol, CMC-urea-activated carbon, and CMC-urea-activated carbon-glycerol. The weight ratio of CMC and urea fertilizer was kept constant at 2:1 since the resulted bioplastics showed higher texture transparency and homogeneity than those of bioplastics with a weight ratio of CMC to urea 1:1. The addition of zeolite increased the tensile strength of the bioplastics by about two times. While, the glycerol addition improved the elongation at break. The release of urea from the bioplastics was slower for bioplastics with zeolite than with activated carbon. The composite bioplastics may serve as a slow-release urea for agriculture.