DEVELOPMENT OF A BIO-BASED PACKAGING MATERIAL FROM SWEET POTATO STARCH

Abstract

A biodegradable, eco-friendly, non-toxic polymer film was developed from sweet potato (Ipomea Batatas (L) Lam) starch. The extracted starch was sun-dried in an aluminium tray for two days before use. Glycerol at pH 6, was used in the plasticization of the starch in an acidic medium of 0.1M HCl. Neutralisation of the medium was done with a basic solution of 0.1M NaOH. The mixture was boiled to a temperature of 200o C, poured into a mould and then dried for 24 hours at 50o C, in an oven, to develop the bio-plastic film. Test specimens were prepared from the film and conditioned at 23o C ± 2o C for 24 hours to investigate its mechanical properties i.e. tensile strength, tensile modulus, extension, load and energy at break in accordance with the American Society of Testing of Materials (ASTM D882). 18.75 g of starch, 75 ml of water, 2.50 ml of glycerol, 22.50 ml of NaOH with 22.50 ml of HCl produced 20 g of bio-film plastics from the compositions. Therefore, a conversion ratio of approximately 1:1 of starch to plastics was obtained in this work. The effects of glycerol on the Mechanical properties were also evaluated. Results revealed that polymer plastic film with tensile strength of 9.26 MPa, Modulus of 175.25 MPa, glass transition temperature (Tg,) of 970 C and melting point of 1200 C falls within the range of ASTM plastic films used for packaging purposes. It was concluded that the bio-film developed can stand as a substitute for the production of shopping bags, sweet wraps, food packaging material for bread, chips, and other fast food.