| Abstract [eng] |
Scientific research and analysis of starch derivatives can contribute to the application of various biomaterials in the production of respiratory devices, replacing conventionally used petroleum-based polymers. In order to reduce the amount of the synthetic part and increase the amount of biomaterial, the focus on more ecological, more compatible with the human respiratory tract and skin, respiratory equipment with adequate filtration efficiency and durability. The research project was carried out to investigate the morphology and properties of starch modification, applicability for the production of micro/nano fibers and to produce a personal respiratory device using electrospinning technology. The work analyzes the changing parameters of the production process and their influence on the sizes of the thread and pore diameters of the modification fabrics. The most optimal conditions under which filter fabrics with the best filtration efficiency are formed have been selected, and the filtration efficiency has been investigated. After the tests, it was confirmed that the starch was successfully modified, the structure was proven by Fourier transform infrared spectroscopy and crystallinity results, it can be shown that the –OH groups of starch were replaced by OSA and acetate fragments, analyzes were compared with the spectra of unmodified starch, respectively. It was additionally found that the initial starch modification has a glass transition temperature Tg – 154 °C, is thermally stable, and loses 5 % of its mass at a temperature of 281 °C (TGA). In order to assess whether the starch modification can be spun using the melt spinning method, filament formation was tested with a plastomater, unfortunately, the filaments were fragile and insufficiently elastic, so the fabrics were spun using electric spinning technology. The modification fibers can be considered hydrophobic because the liquid did not wet the fibers and the wetting angles for the fabrics were between 80-140°. Dependences of voltage, concentration, flow rate and distance (from feed to collection drum) on the diameter of filter fabric threads and pores were investigated. The most optimal conditions for the production of the respiratory tract product were selected: 10 % (m:V) solution in formic acid, voltage - 22 kV, flow rate - 1.0 ml/hour, at a distance of 14 cm. The filter fabric consists of nanofibers of modified starch, which are covered with a polyamide base. The resulting single-layer filter retained aerosol particles with an efficiency of 88 % and had a pressure drop of 10.33 Pa at a filtration speed of 5.32 m/s. It was determined that the average thread diameter of the filter fabric of the respiratory device was 0.61±0.27 μm, and the average pore diameter was 3.13±1.00 μm. |
