Abstract: This process involves feeding cellulose into an extruder with an acid solution. The extruder is comprised of a screw and a barrel. The screw is rotated so as to pressurize the cellulose, and the cellulose undergoes acid hydrolysis and forms microcrystalline cellulose. The invented process can be accomplished by using pure cellulose or a lignocellulosic material as the starting material. If a lignocellulosic material is used, then a basic solution is added to it and the lignocellulosic material is fed through an extruder so as to obtain a mixture comprising lignin, hemicellulose and cellulose. The lignin and hemicellulose are extracted and the remaining cellulose is processed, as discussed previously, to form microcrystalline cellulose.

Abstract: A foam that is the extrudate of a mixture of a biodegradable polymer, starch, talc, and a blowing agent is provided. This foam is made by extruding a mixture of the above-listed components. This foam is water-resistant and in some variations waterproof making it an effective packing material. Still further, this foam is biodegradable, and thus, it can be disposed without creating environmental waste. In addition, the foam may be extruded into sheets and then thermoformed to form various articles.