| abstract |
This invention discloses a method of preparing and extruding biodegradable starch blends into biodegradable products in such a way that preprocessing steps, such as gelatinizing or destructurizing of the starch, are not required. Unprocessed raw starch is combined with biodegradable copolymers such as polyvinyl alcohol (PVOH), or ethylene vinyl alcohol (EVOH), a nucleating agent, and a plasticizer. The combination may be processed using a twin-screw mixer, and blown into a film. The method described in this invention alleviates pre-preparation steps, reduces the cost and time required to prepare and extrude starch-based biodegradable materials, eliminates the need to use expensive pre-processed starch, and results in a substantially completely biodegradable product. |