Thermoplastic starch

The thermoplastics processing of natural hydrophlic polymers in the presenc e of water is a recent development with very wide possible applications. Ev entually, oil-based polymer materials could be replaced in many application s by inexpensive, natural products from renewable resources. As with conven tional thermoplastics, hydrophilic polymer melts may be processed by inject ion moulding and extrusion. The present contribution focuses on the injecti on moulding of potato starch. The basis of the processing and the thermal c hanges occurring during processing are described. In addition, the rheologi cal behaviour of the starch-water melts during processing is analysed quant itatively to give apparent melt viscosities. The thermal and mechanical pro perties of moulded starch materials and the drug delivery behaviour of star ch capsules are discussed.