The effects of the addition of corn husk fibre, kaolin and beeswax on cross-linked corn starch foam

Abstract

Significant efforts have recently been made to improve the physical properties of starch foams formed using baking processes. For example, cross-linking starch with 0.126g/kg glyoxal considerably reduces the baking time, density and water absorption of starch foams. In this study, we attempted to further develop the physical properties of glyoxal cross-linked starch foam by adding corn husk fibre, kaolin, beeswax and combinations of these products. We also studied the effects of these components on the microstructure and physicochemical and mechanical properties of trays. Starch-based trays in which additives were used showed improved water resistance. The water absorption capacities of the trays were 13%, 14% and 9% when combinations of kaolin/beeswax, fibre/beeswax and fibre/kaolin/beeswax were added, respectively.We found that baked foams formulated with only cross-linked starch had higher tensile and flexural strength than composite foams of either cross-linked starch/kaolin or cross-linked starch/beeswax. However, using combinations of additives further increased the tensile and flexural strength of baked foams, with the exception of cross-linked starch/beeswax/kaolin composite foams. Furthermore, all mechanical properties of the trays were superior to those produced using only cross-linked starch.