ULTRASONIC EFFECTS ON THE PROPERTIES OF POTATO STARCH BASED BIODEGRADABLE POLYMERS
The purpose of the research was to study the properties of composite biopolymers obtained from potato starch. Nowadays this issue is of great scientific interest all over the world due to the problem of traditional plastics disposal and its harmful effects on the environment, which are constantly growing from year to year. The application of biopolymers based on various kinds of starches including potato starch is interesting because this feedstock is nearly unlimited and is constantly renewed. However, using starch-based biopolymers for the production of disposable houseware or packaging is restricted by certain difficulties connected with its further usage. The main drawback is increased moisture absorption: with the increase of starch content the fragility of a biodegradable film increases. Thus for solving these problems we changed the ratio of the biopolymer constituents which were exposed to ultrasonic treatment in a cooling system in order to obtain biodegradable films with improved deformation and mechanical characteristics. In order to obtain a biodegradable water-soluble film from the mixture of starch and additional film-forming substance, sodium alginate, we added there a plasticizer - glycerin. The test samples of composite polymers were exposed to ultrasound using an acoustic source of elastic oscillations (“Volna”, UZTA-0,4/22-ОM), with a frequency of 22 ± 1,65 kHz and maximum power of 400 W. The results of the tests have shown that a film obtained from the mixture of starch and sodium alginate and exposed to ultrasound in the optimal mode has the lowest resistance to molds which proves its biodegradability.