TREATMENT OF STARCH WITH VARIOUS ADDITIVE S ON PLASTIC PROCESSING PLANTS

Starch is used as the base of biodegradable polymers, because its macr omolecular structure is similar to the structure of synthetic polymers . In order to process the starch on polymer processing machines, it is necessary to hydrate respectively gelatinize the starch granules. The influence of different additives, e.g. urea, ammonia, HEMA and glycol s on the gelatinization is investigated. Fur ther the compatibility of starch with two different polyethylene-co-acrylic acid types is shown . Some material combinations are processed on a twin screw extruder to pellets. To be able to give information about the mechanical and phys ical properties of the processed combinations, specimen are injection molded and tested in a short time tensile test. The shrinkage is monit ored over a period of 4-6 weeks. The resistence of the materials to so aking in water is discussed. Material combinations are found, whose me chanical and physical properties allow an industrial application. By a dding synthetic polymers the properties of destructurized starch is dr astically improved and maintained over an extended period of time.