The potential of using sweet corn (Zea mays Saccharata) husk waste as a source for biodegradable plastics

Synthetic plastics are generally challenging to degrade in the environment and capable of releasing harmful chemicals upon improper disposal, endangering both wildlife and humans. Therefore, this study aimed to develop cellulose-based bioplastics from corn husk waste and carboxymethyl cellulose (CMC) using sorbitol as a plasticizer. The effect of corn husk delignification, CMC addition, and variations in sorbitol concentration were investigated. The results of Chesson's test showed that the delignification process increased cellulose content to 77.30% and decreased lignin content to 3.6%. Additionally, Fourier-transform infrared (FTIR) demonstrated the effective removal of lignin and hemicellulose components from corn husk fibers. X-ray diffraction (XRD) analysis indicated the elevation of corn husk crystallinity from 63.97% to 80.83% after the treatment. Scanning electron microscopy (SEM) revealed bioplastic morphologies featuring porous and smooth surfaces juxtaposed with uneven and lumpy characteristics. Biodegradation assessment yielded a peak value of 33.4% under a composition comprising 3% CMC and 1.5% sorbitol. The swelling test performed on corn husk bioplastic samples produced values ranging from 52.89 to 66%, with the highest value recorded at 66% for the bioplastic formulation consisting of 3% CMC and 1.5% sorbitol. Resistance testing on samples containing 3% CMC, with a soaking time of four days in acidic environments, indicated a maximum weight loss of 61.3% (10% H2SO4) and 62.5% (20% H2SO4). Alkaline resistance tests displayed a 95.6% (10% NaOH) and 94.6% (20% NaOH) weight loss under similar conditions. These results suggested the potential utility of corn husk waste as a viable bioplastic source, promoting the circular economy concept in Indonesia while mitigating greenhouse gas emissions, reducing waste volume, and increasing rural economic growth. © 2023 Elsevier B.V.