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Biofilm and bionanocomposite films were synthesized from polyvinylpyrrolidone (PVP), chitosan (CS), citric acid (CA), and zinc oxide-nanoparticles (ZnO-NPs). Effects of gamma-irradiation dose and ZnO-NPs concentrations; 0, 0.1, 0.3, 0.6, 0.9, 1.2, and 1.5 (wt./wt.)% were studied. Biofilms and bionanocomposite films were characterized by Fourier transform infrared, Raman spectroscopy, transmission electron microscopy, thermal gravimetric analysis, X-rays diffraction, energy dispersive X-ray, and mechanical properties to identify structure of biofilm and bionanocomposite films. Swelling (g/g)% and gelation (g/g)% of biofilms were carried out at diverse compositions of PVP to CS of (1/1), (1/2), and (2/1) (v/v). Swelling (g/g)% results of (1/1), (1/2), and (2/1) (v/v) were 116, 110, and 126, respectively. Values of highest and lowest gelation (g/g)% of (1/2) and (2/1) (v/v) are 98.0 +/- 1.8 and 85.0 +/- 2.6, respectively at 30 kGy. Water vapor transmission rate was studied for films and exposed 3450 +/- 4.1 and 185.8 +/- 1.2 (kg/m(2).day) for open bottle and (PVP/CS/PCA)/(ZnO-NPs-1.5), respectively. Values of water solubility (g/g)% were investigated and found 30.21 +/- 1.3 and 15.4 +/- 2.5 for (PVP/CS/PCA)/(ZnO-NPs-0) and (PVP/CS/PCA)/(ZnO-NPs-1.5), accordingly. Bionanocomposite films displayed a broad-spectrum antimicrobial activity against Gram-negative bacteria and Gram-positive bacteria. (PVP/CS/PCA)/(ZnO-NPs-0.1) showed lowest inhibition zone; 4 +/- 0.2, 9 +/- 0.5, 19 +/- 0.1, and 8 +/- 0.3 (mm) compared with (PVP/CS/PCA)/(ZnO-NPs-1.5) of highest inhibition zone; 16 +/- 0.5, 28 +/- 0.2, 33 +/- 0.6, and 18 +/- 0.3 (mm) for Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus, respectively. Antimicrobial activity increased with increasing ZnO-NPs concentrations. Biodegradation of biofilms and bionanocomposite films were examined under soil from 0 to120 days. Results of weight loss (g/g)% at 120 days of (PVP/CS/PCA)/(ZnO-NPs-0) and (PVP/CS/PCA)/(ZnO-NPs-1.5) are 72 +/- 4.5 and 47.5 +/- 3.8, respectively. Bionanocomposite films were used in food preservation of fresh cherry tomatoes for 30 days and showed goodness. Therefore, these results suggest that the possibility of using bionanocomposite films in food-packaging applications.

来源平台：POLYMER ENGINEERING AND SCIENCE