| Abstract [eng] |
Master‘s thesis theme – „Starch – based biodegradable films: preparation and properties“. The aim of this work – to obtain biodegradable coatings from starch and to study their characteristics and effect on fertilizer solubility. Generalized theory of fertilizer efficiency and an overview of the latest fertilizer efficiency and quality improvement trends, characteristics of controlled release fertilizer were reviewed in first chapter. Furthermore, classification, types and assortment, methods of production also advantages and disadvantages of controlled release fertilizers were discussed. In the experimental part of the study, the selection of starch films production methods, studies of films stability and their mechanical properties were demonstrated. There were three different kinds of starch used: potato starch, wheat starch and Kollotex (modified potato starch). Experimental data was analyzed by using various instrumental analysis methods and was determined that the origin of starch directly influences physical and chemical properties of produced polymer films. Urea – the most widely used nitrogen fertilizer because of high nitrogen content (46,6%), so it is the most appropriate component in controlled release fertilizer production. To assess the influence of starch films types and thickness to urea dissolution rate test was carried out with a special dissolution capsule, which allowed to create urea granule coating with polymer coat simulation model. Urea concentration variation in solutions at different dissolution duration and using various film thicknesses was examined. Moreover, films biodegradation (degradation) rate test was carried out in different environments: soil and sand. During biodegradation rate test the loss of mass was measured. IR analysis was used to evaluate the changes results of different types of starch and compared with each other. Based on experimental data, technological recommendations and the principal technological scheme were suggested. |
