A review: Starch-based composite foams

The large quantities of the petroleum-based foam materials used have raised concern due to their negative effects on the environment, predominantly single-use articles in packaging applications. Thus, considerable efforts have been put forth to develop environmentally friendly alternatives and, in particular, starch foams. Many techniques including extrusion, hot-mold baking/compression, microwave heating, freeze-drying/solvent exchange, and supercritical fluid extrusion can be used to produce starch foams with different cellular structures and properties. Starch by itself is, however, rather weak and water sensitive. To improve microstructure, mechanical and thermal properties, moldability, water resistance, lightness and other properties of starch-based foams, many approaches, e.g., chemical modification of starches, blending with various biodegradable polymers, incorporation of natural fibers, and addition of nanofillers, have been attempted and are intensively reviewed in this article.