The influence of electron and gamma irradiation on the properties of starch:PVA films – the effect of irradiation dose

The paper discusses the effect of ionizing radiation on the functional properties of the biodegradable starch:PVA films. The analysis is related to the possible use of the material for packing the products (particularly, food) that are predicted for radiation decontamination and to the potential modification of the material by radiation treatment. Our previous results have shown that the influence of ionizing radiation on the films’ properties varied for the specific compositions (differing in starch:PVA ratio or the type of substrates) and depended on irradiation conditions. However, these studies considered only the irradiation performed in gamma chamber or in e-beam using a dose of 25 kGy. Therefore, the present study deals with the effect of the irradiations performed using various doses on the selected promising starch:PVA composition. The films characterized by starch:PVA weight ratio of 45:55 was obtained by solution casting and irradiated with fast electrons in air and with ⁶⁰Co gamma rays in nitrogen applying the doses of 5, 10, 20, 25, 30, 50, and 75 kGy. No regular dependence has been noticed between the composition of films (differing in the starch and PVA content) and the intensities of the particular bands in the UV-VIS DRS spectra after irradiation. The results indicated strong interaction of the starch and PVA components in the films and the occurrence of specific reactions in each composition upon irradiation. No special differences were observed between tensile strength and Young’s modulus of the non-irradiated films characterized by the starch:PVA ratio equal to 45:55 and the samples irradiated using doses in the range of 5–75 kGy. Similarly, no differences were observed in both cases between the swelling capability of the non-irradiated and the irradiated films. However, it can be deduced that solubility in water increased when the radiation dose increased. The results show that using the doses till the range 25 kGy does not cause an essential change of all the examined properties of the starch:PVA (45:55) films. Accordingly, starch:PVA (45:55) films might be considered suitable for packing food predicted for radiation decontamination.