Biodegradable plastics from cassava starch

In the past few decades, there has been a marked advance in the development of biodegradable plastics from renewable resources, especially for those derived from starch-based materials. The goal of this development is to obtain biodegradable plastics that perform as well as traditional plastics when in use and which completely biodegrade at disposal. Several starch-based plastics have been introduced into the market, and are used in some applications now. Starch foam is one of the major starch-based packaging materials. It is produced by extrusion or compression/explosion technology. This product has been developed as a replacement for polystyrene which is used to produce loose-fillers and other expanded items. Another type of starch-based plastics is produced by blending or mixing starch with synthetic polyester. For this type of biodegradable plastics, granular starch can be directly blended with polymer, or its granular structure can be destructurized before being incorporated into the polymer matrix. The type of starch and synthetic polymer as well as their relative proportions in the blends influence the properties of the resulting plastics. The last group of starch-based plastics is polyesters that are produced from starch. The major starch-derived polyesters in the market now are polylactic acid and polyhydroxyalkanoate. Experimental studies have demonstrated that cassava starch could be used for making various types of packaging products. As a major source of starch in tropical and subtropical regions, cassava is a promising raw material for the development of biodegradable plastics in these areas. This article reviews the major types of starch-based biodegradable plastics and their relevant manufacturing processes. The research activities concerning cassava starch in the development of biodegradable packaging materials are emphasized.