In this work, a new eco-friendly method for the treatment of poly(3-hydroxybutyrate) (PHB) as a candidate for food packaging applications is proposed. Poly(3-hydroxybutyrate) was modified by bacterial cellulose nanofibers (BC) using a melt compounding technique and by plasma treatment or zinc oxide (ZnO) nanoparticle plasma coating for better properties and antibacterial activity. Plasma treatment preserved the thermal stability, crystallinity and melting behavior of PHB‒BC nanocomposites, regardless of the amount of BC nanofibers. However, a remarkable increase of stiffness and strength and an increase of the antibacterial activity were noted. After the plasma treatment, the storage modulus of PHB having 2 wt % BC increases by 19% at room temperature and by 43% at 100 °C. The tensile strength increases as well by 21%. In addition, plasma treatment also inhibits the growth of Staphylococcus aureus and Escherichia coli by 44% and 63%, respectively. The ZnO plasma coating led to important changes in the thermal and mechanical behavior of PHB‒BC nanocomposite as well as in the surface structure and morphology. Strong chemical bonding of the metal nanoparticles on PHB surface following ZnO plasma coating was highlighted by infrared spectroscopy. Moreover, the presence of a continuous layer of self-aggregated ZnO nanoparticles was demonstrated by scanning electron microscopy, ZnO plasma treatment completely inhibiting growth of Staphylococcus aureus. A plasma-treated PHB‒BC nanocomposite is proposed as a green solution for the food packaging industry.

Classification numbers: PACS: 52.70.Kz, 52.80.TnAtmospheric pressure planar RF 13.56 MHz discharge in Ar gas generated in long gap is investigated. The discharge operation with and without dielectric barrier on the electrodes is studied as a function of the applied power and gas flow. The source afterglow is characterized and analyzed for possible large scale biomedical applications where low gas temperature is required. The discharge is studied by relative and absolute emission spectroscopy. The gas temperature as low as 330±50 K is determined from rotationalvibrational band of OH emission. The absolute value of the discharge continuum irradiation is used to determine the electron density and the electron temperature. The electron-atom and electron-ion contributions to the Bremsstrahlung radiation are calculated and compared with measured spectra. The electron density of 1.91×10 20 m -3 and electron temperature of 1.750.25 eV are measured in the discharge without dielectric barrier. It is found that presence of the dielectric has negligible effect on electron temperature whereas electron number density is almost 6 times lower in the discharge with dielectric barrier.

We present results describing the behavior of a radiofrequency plasma jet discharge with bare electrodes generated in argon during a continuous pressure increase from low (10 mbar) to atmospheric pressure (1000 mbar). Both the interelectrodic space and the expansion plasma regions were studied by means of imagistic, electrical and spectral methods. It is shown that different operation regimes are encountered when pressure changes from low to atmospheric values, with a quasi-unstable or smooth transition between them in the intermediate pressure range. However, the continuous operation of the plasma beam discharge source in the non-thermal regime is demonstrated for the entire pressure range.

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