Characterization And Development of Nut Grass (Cyperus rotondus L.) Biodegradable Plastic

Abstract

Plastic pollution has profoundly affected Earth’s ecosystems, posing a grave threat to the balance of nature. Conversely, Cyperus rotundus Linn, commonly known as nut grass, is one of the world's worst weeds, infesting a wide range of crops and reducing yields by 20 to 90 percent. Notably, the starch granules in its tubers have a significant amylose concentration of 26.73 percent and a yield of 24.1 percent on a dry weight basis. This study aims to characterize and develop a biodegradable plastic using starch extracted from nut grass tubers. The method and formulation of Marichelvam (2019) were used for bioplastic production, with five treatments and three replicates each. Each treatment had different nut grass starch compositions (10 g, 7.5 g, 5 g, and 2.5 g) combined with glycerol, citric acid, gelatin, and distilled water. The study's findings revealed that Treatment 4 was the most effective in terms of elongation at break (35.6580%), water absorption (41.875%), and biodegradability (84.45266%). Moreover, Treatment 3 exhibited the highest tensile strength at 4.76504 MPa, while Treatment 2 had the highest density of 1.41193 g/mL. All treatments experienced significant weight loss between 260°C and 350°C. The FTIR spectra revealed the presence of C-H stretches at 2926.03/cm, 2857.05/cm, 1455.83/cm, 1409.83/cm, 1365.55/cm, 1238.82/cm, 925.52/cm, 860.85/cm, 822.05/cm, 810.55/cm, and 761.69/cm, indicating the starch structure present in all bioplastic samples. Based on the results, it is concluded that the most effective formulation for producing bioplastic from nutgrass tuber starch is Treatment 4, with a 5 g nut grass starch composition.