No abstract

Abstract. The cornstarch: poly(vinyl alcohol) (PVA) fi lms characterized by the alternating ratio of starch: PVA (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100) and containing 30% of glycerol were prepared by solution casting. The fi lms were irradiated with an absorbed dose of 25 kGy with gamma rays in a vacuum and with fast electrons in the air. The fi lms characterized by a high content of starch appeared stiff, while the fi lms characterized by a high content of PVA were highly fl exible. The tensile strength and fl exibility, as well as swelling and hydrophilicity, increased with the increase in the PVA content in the fi lms. However, the tensile strength and wetting angle values achieved a minimum at an intermediate composition. It was found that irradiation enables to reduce hydrophilicity of the fi lms accompanied by a decrease in their fl exibility. No general conclusion concerning the effect of irradiation on tensile strength and swelling behavior can be derived. An increase in the homogeneity of the fi lms and an increase in the compatibility of their components was found by scanning electron microscopy (SEM). Strong interactions of the starch and the PVA components were discovered by diffuse refl ectance spectroscopy. Degradation was found to be the prevailing process occurring in the fi lms under the infl uence of irradiation. The possible accompanying crosslinking is discussed in terms of the gel content in the samples. Creation of various oxidation products in the fi lms characterized by the modifi ed composition was observed under the infl uence of irradiation carried out in the air. Basing on the obtained results it can be supposed that the selected starch-PVA compositions might appear useful as packagings of the products predicted for radiation decontamination.