DOI: https://doi.org/10.55373/mjchem.v25i3.342

Keywords: Water spinach bioplastic; vegetable-based bioplastic; biodegradable plastics

Abstract

Starch-based bioplastics is often used in the manufacturing of bioplastics. However, starch-based bioplastic is prone to have low mechanical properties and degradation due to water absorption. Currently, starch-based bioplastics are often added with fiber to increase their resistance to abrasion, mechanical and barrier properties. The addition of water spinach stem, one of the agro-industrial by product with plasticizer and surfactant, will improve the water absorption, mechanical and wetting properties of starch-based bioplastic. This study formulated a bioplastic using water spinach stem (WSS), cassava starch, glycerol, palm oil, and Tween-80 to produce bioplastic films reinforced from a renewable resource. The percentage of WSS was manipulated through the study to observe the water contact angle, water absorption, and mechanical properties of water spinach bioplastic (WSB). The film was casted in the oven at 80 ℃ for 4 hours. Then the WSB was cured at room temperature for 24 hours. The results demonstrated that the highest value of water contact angle was 79.85° at 17 wt% of WSS content. Besides that, 9 and 17 wt% of WSS revealed the lowest water absorption which can maintain for 2 hours. The presence of lignin in WSS enhances the hydrophobicity of WSB. However, greater amount of WSS beyond that would increase the water absorption and hence influence the tensile strength, tensile modulus, and elongation at break of WSB. This alternative opens up possibilities for bioplastics obtained from food waste.