The development of biodegradable plastic with natural colourant as packaging material

Abstract

The aim of this study is to develop biodegradable plastic with natural colourants as packaging material. Blends of anthocyanin and bromocresol purple (BCP) as biological and chemical colourants respectively, tapioca starch, glycerol, polyethylene grafted maleic anhydride (PE-g-MA), clay, nanocomposites and low density polyethylene (LDPE) with different formulation contents for five types of blends were prepared using a lab scale twin screw extruder. A series of low density polyethylene (LDPE) with different blends formulation were developed via blow film extrusion. The morphology and properties of the blends were evaluated by using a scanning electron microscope (SEM). The dispersion of tapioca starch in the LDPE matrix was homogeneous and mechanical properties of the films were improved with the addition of glycerol. The interfacial adhesion between tapioca starch and LDPE was further improved by the addition of PEg-MA according to the morphological structure shown by SEM micrographs, thus enhanced the mechanical properties of the films. Formulations containing 35% tapioca starch with fairly high concentrations of additives indicate the importance of the concentration of starch and the presence of additives on the biodegradability of tapioca starch-LDPE film blends.