NUKLEONIKA 2010, 55(2):233-242

 


PRELIMINARY STUDIES OF THE INFLUENCE OF STARCH IRRADIATION ON PHYSICOCHEMICAL PROPERTIES OF FILMS PREPARED
USING STARCH AND STARCH-SURFACTANT SYSTEMS



Krystyna A. Cieśla, Andrzej Nowicki, Marek J. Buczkowski

Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland


The influence was studied of potato and wheat starch irradiation on physicochemical properties of films, prepared using either starch alone or a composition of potato starch with three surfactants: sodium laurate, sodium palmitate and cetyl-trimethyl-ammonium bromide (CTAB). The surfactants were introduced at a level of 0.038÷0.075 g per 1 g of starch. This corresponds to 0.136–0.222 mmol/g, depending on the surfactant type and its amount used. Irradiations were carried out using 60Co radiation with doses of 5, 10, 20 and 30 kGy. Films were prepared with addition of glycerol (0, 20 or 30% in terms of starch mass) by means of casting from the gelatinized starch or starch-surfactant solutions. With the purpose to characterize the films, mechanical tests (using an Instron instrument) and the wetting angle measurements were performed. The effect was determined of the storage and conditioning in an atmosphere characterized by the various moisture content on the properties of films with various compositions. The results show the radiation-induced improvement of hydrophobic properties of the films prepared using potato and wheat starch, and the selected potato starch-surfactant compositions. Improvement of strength and flexibility was obtained in the case of potato starch films, while in the case of wheat starch films the increase of strength was accompanied by a decrease in flexibility. Improvement of the functional properties of potato starch films corresponds to the improvement of their structural properties, found by scanning electron microscopy (SEM). The possibilities of modification of the films properties by modification of composition and radiation treatment were discussed.


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