Biodegradable Foam from Cassava Starch Blended with Water Hyacinth Fiber: Effects of Polyvinyl Alcohol Content

Abstract

Our previous investigation revealed that the addition of water hyacinth fiber (WHF) and polyvinyl alcohol (PVA) enhanced the mechanical properties of cassava starch-based foam. However, the effect of PVA concentration on the mechanical properties of starch foam is still unclear. Therefore, this study examined the effects of various concentrations of PVA on the foam’s quality and production process. Four levels of PVA (0, 1, 2, and 3% w/w) were tested on the mixed dough of cassava starch and 15% of WHF. The foam was made by baking the dough on a thermopressing machine at a temperature of 190 °C for 3 min. The quality level of foams was determined by their physical and mechanical (compressibility, water adsorption, density, color appearance, and biodegradability) properties as well as the practicality of the dough preparation and baking processes. As a result, the addition of PVA significantly affects the mechanical properties and ease of making dough. A higher concentration of PVA contributed to a better mixture of the dough, resulting in a smoother mixing process that led to foams with stronger mechanical properties. Nevertheless, the application of 2% and 3% PVA did not make a significant difference in the mechanical and physical properties. Foam with 2% PVA showed 32 N/mm2 of compressibility, 10% water absorptivity, 12% water content, and good biodegradability, with 87% of the material lost during 30 days of burial in the soil.