The PhD thesis is based on three scientific papers from the field of development of sustainable polymer packaging materials. The research for these papers has resulted in new, different, sustainable, polymeric packaging materials, using mostly locally available raw material sources, which could serve as an alternative to conventional petroleum-based materials in the future. Coatings from renewable sources have also been developed, which serve mainly to improve the barrier properties of papers and may in the future provide a substitute for some synthetic coatings.
In the first phase of the research, a new, flexible, thin material, potentially useful for packaging purposes, was obtained by electrospinning from sludge produced during the treatment of municipal wastewater. The sludge was cleaned using ethylenediaminetetraacetic acid prior to the electrospinning process. The composition and purity of the sludge were determined using Fourier transform infrared spectroscopy, near-infrared spectroscopy, and thermogravimetric analyses. For the most accurate analyses, nuclear magnetic resonance was used. The mechanical properties of the newly developed material were analysed by tensile tests and its homogeneity and morphological characteristics were analysed by electron line microscopy.
In the second phase of the research, thin, flexible films were produced by a casting process, the main components of which were: bacterial nanocellulose (obtained from an alternative raw material source - vinegar nut), nanocrystalline and nanofibrillated cellulose, alginate, and chitosan. All film components were characterised prior to casting using different analytical techniques. The newly developed films were characterised mainly in terms of mechanical-physical properties (tensile properties) and barrier properties (water vapour and oxygen permeability), and the influence of composition on these properties will be determined.
In the last part of the research, the influence of different coatings on the barrier properties of commercially available, industrially produced paper was investigated. Initially, starch-based coating blends were prepared with different proportions of lignins from different raw material sources added. The coating blends were then applied to the selected paper. By measuring the water vapour permeability, fat, and oil resistance, etc. of the coated papers, the influence of the bio-based coatings on the barrier properties was determined, as well as the mechanical and physical properties of the paper.
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