Abstract
In order to reduce the use of expanded polystyrene (EPS) foam that is a source of solid wastes in the environment, biofoam made of corn starch/glutinous rice flour blend was developed with an aim to replace EPS foam. Some additives such as guar gum, beewax, magnesium stearate and glycerol were also added and kaolin was used as a reinforcing agent. Effects of kaolin content (5, 10, and 15 phr) on physical, mechanical, and thermal properties of the foam were investigated. It was found that with the addition of kaolin, the foam density, the size and fraction of opened cells increased, accordingly. In contrast, the closed cells showed no change in size, while the thickness of cell wall increased. Furthermore, with increasing in kaolin content, the foam exhibited the reduction in moisture content as well as water absorption capacity, resulting in good dimensional stability after soaking in water for 30 min. Although the addition of 15 phr kaolin brought about the 44% reduction in elongation at break, Young’s modulus of the foam increased by 87%. Besides, it was also found that melting temperature of the foam can be increased with increasing kaolin content.
Keywords : Biofoam, Corn starch, Glutinous rice flour, Kaolin
