Effects of Glycerin and Carboxymethyl Cellulose on the Mechanical, Water-solubility and Soil-burial Biodegradation Properties of Corn-starch Bioplastic Films
Patience Uju Onyebuchi
Department of Science Laboratory Technology, Faculty of Life Sciences, Modibbo Adama University, Yola, Adamawa State, Nigeria.
Benjamin Abu Emmanuel *
Department of Chemistry, Faculty of Sciences, Federal University of Health Sciences, Otukpo, Benue State, Nigeria.
Lawan Yikura
Department of Chemistry, Faculty of Sciences, Federal University of Health Sciences, Otukpo, Benue State, Nigeria.
Burbwa Vihiior
Department of Chemistry, Faculty of Sciences, Federal University of Health Sciences, Otukpo, Benue State, Nigeria.
Augustine Ekpo
Department of Chemistry, Faculty of Sciences, Federal University of Health Sciences, Otukpo, Benue State, Nigeria.
Abdurazaq Maiwad
Department of Science Laboratory Technology, Faculty of Life Sciences, Modibbo Adama University, Yola, Adamawa State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Starch-based films are being investigated as potential alternatives to petroleum-derived plastics, but brittleness and sensitivity to water restrict their performance. This study examined the separate effects of glycerin and carboxymethyl cellulose (CMC) on corn-starch films prepared by solution casting. The glycerin series contained 0, 10, 20, 30 or 40 mL of glycerin per 10 g of starch, while the CMC series contained 0, 1.0, 1.5, 2.0 or 2.5 g of CMC at a constant, but unspecified, glycerin level. Tensile strength, elongation at break, water solubility and soil-burial mass loss were assessed. Across the glycerin series, tensile strength decreased from 32.0 to 6.0 MPa, while elongation at break increased from 10.0% to 65.0%. Water solubility increased from 33.0% to 82.0%, and soil-burial mass loss increased from 27.5% to 88.0%. In the CMC series, tensile strength rose from 12.0 to 90.0 MPa and elongation at break from 15.0% to 75.0%; water solubility declined from 34.9% to 6.38%, while soil-burial mass loss increased from 5.8% to 55.0%. The findings indicate different property trends for the two additive series. However, the series cannot be directly compared because their baseline formulations differ. In addition, soil-burial mass loss does not establish microbial mineralisation. These results provide preliminary information for selecting corn-starch film formulations, subject to further methodological validation.
Keywords: Bioplastic, corn starch, glycerin, carboxymethyl cellulose, tensile properties, biodegradation