Effect of glycerol concentration on mechanical characteristics of biodegradable plastic from rice straw cellulose

Abstract

Biodegradable plastic or bioplastic as eco-friendly polymers are used for replacement of commercial plastics in the market due to its biodegradability and non-pollutant properties. Bioplastics give many advantages for food packaging and medical purposes. Bioplastics can be manufactured from natural fiber as the main source. One of the main potentials of natural fibers in Indonesia is rice straw. The aims of this research were to manufacture bioplastics and to study their physical and mechanical characteristics. Bioplastics were made by mixing rice straw pulp as main cellulose source with plasticizer and chitosan as additives. Glycerol as a plasticizer was added with the variation of glycerol concentrations of 25%, 30%, and 35%. The test done on the bioplastics were molecular structure analysis using Fourier-transform Infrared Spectroscopy (FTIR), water swelling test, oil swelling test, tensile strength test using Universal Testing Machine, and soil-based biodegradation test. Results showed that best bioplastics (bioplastic with 35% glycerol) in this study contains functional groups of N-H (3393.9 cm -1 ), O-H (3391cm -1 ), C-H (2938.68 cm -1 ), C-O (1111.05 cm -1 ), C-N (1230.64 cm -1 ). It resulted 86.866% in water swelling test, 29.109% in oil swelling test, 6 MPa in tensile strength test, and it broke at 65% elongation. During biodegradation test for 15 days under dry soil and wet soil, the weight of the bioplastic reduced 18.496% and 21.317%, respectively.