Sugar beet pulp as biodegradable plastic in disposable food containers
U.S. Department of Agriculture (USDA) scientists and university cooperators have developed a biodegradable plastic that could be used in disposable food containers. To make the plastic, Agricultural Research Service (ARS) scientists incorporated biodegradable sugar beet pulp, which is the leftover residue from sugar extraction, with a biodegradable polymer. The result is thermoplastic composites that retain mechanical properties similar to polystyrene and polypropylene, the compounds used to make white, spongy food packages.
Researchers at Washington State University (WSU) developed the thermoplastic, which is manufactured from both sugar beet pulp and a biodegradable polymer called polylactic acid, or PLA, using a twin screw extruder. PLA is a commercially available polymer derived from the sugars in corn, sugar beet, sugarcane, switchgrass and other plants, all of which are renewable feedstocks. Extrusion is a cost-effective manufacturing process that is popularly used in large-scale production of food, plastics and composite materials.
The researchers showed that up to 50 percent sugar beet pulp can be incorporated with PLA to produce biodegradable thermoplastic composites that are similar to the petrochemical compounds used in making spongy disposable food packages (News Item USDA,