Thermoplastic starch as a component of film-forming compositions with degradable properties

Abstract

A review of the literature on the production of thermoplastic starch, which is an integral part of biodegradable polymer compositions. The analysis of plasticizing additives, influence of their functional groups, chemical structure and technological parameters on physical and mechanical properties of starch compositions is carried out. The list of plasticizing additives studied should include: glycerin, water, polyethylene glycol, polypropylene glycol. Sorbitol, formamide, xylitol, dimethyl sulfoxide, gelatin, maleic anhydride, epoxidized compounds are defined as structure-forming additives. To improve the physical and mechanical properties of the starch, the addition of crosslinking agents such as citric, boric, or ascorbic acid has been proposed. According to the above review of studies, it can be stated that when creating thermoplastic starch, it is mandatory to use both plasticizing components and structure-forming, which allows the processing of thermoplastic starch by extrusion with subsequent granulation. Thermoplasticized starch due to various plasticizing additives and technological parameters of its production acquires a wide range of characteristics, which solves the problem of creating biodegradable film-forming materials. Depending on the goals, the second component of such materials may be synthetic polymers: polyethers, polycaprolactone, polyolefins, polyterephthalates, PVA and others. Technological parameters of processing in the extrusion process range from 115 °C to 190 °C in the extrusion process, which does not establish an optimized technology for thermoplastic starch and requires further research.