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Analysis of the influence of electrospinning process parameters on the morphology of poly(lactic acid) fibres

Matysiak W., Kapica A, Tański T., Dubiel A.

Archives of Materials Science and Engineering

2019

Vol. 96, nr 2

73--78

Purpose: The article focuses on the production of polymer nanofibres from poly(lactic acid) using the electro-spinning method, i.e. the technique of forming fibres in an electrostatic field. The main aim of the publication was to analyse the influence of the distance between electrodes on the morphology of one-dimensional polymeric materials obtained. Design/methodology/approach: In the practical part of the study solutions of polylactide in acetone and a mixture of chloroform/dimethylformamide (DMF) were produced. After 72 hours of mixing, no homogeneous solutions were obtained, therefore a solution consisting of a polylactide dissolved in chloroform was prepared, to which dimethylformamide was added in order to dilute the mixture. The morphology of the nanostructures obtained was analysed by means of a scanning electron microscope (SEM) equipped with an X-ray energy dispersion spectrometer (EDS), which allowed to analyse the chemical composition of the nanofibres produced. The electro-spinning method used to obtain fibres is characterized by high versatility - it gives the possibility to produce fibres from a wide range of polymers. Electro-spinning is also an economic method, and spinned fibres have a wide application potential. Findings: Nanofibres obtained by electro-spinning from the previously produced solution, regardless of the distance between the nozzle and the collector (10 or 20 cm) did not show any significant discrepancies in the values of measured diameters. Fibres obtained at increased distance between electrodes (20 cm) are characterized by a smaller average diameter value, but the difference is small, fluctuating between 48-49 nm. In the case of the sample formed during electro-spinning at the distance of the nozzle - collector equal to 10 cm and the sample produced at the distance doubled, no defects in the structure of the obtained nanofibres were observed. The analysis of topographic images of surfaces produced in the course of nanostructures' work did not show any significant influence of the distance between the nozzle and collector on the diameter of fibres. No defects in the structure of one-dimensional polymer materials obtained allowed to state that the distance between the nozzle and the collector in the range of 10-20 cm is the optimal parameter of the electro-spinning process allowing to obtain smooth, untangled fibres. Practical implications: The fibrous polymer mats obtained during the electro-spinning process of polylactide can be used as protective clothing materials, as drug delivery systems, as tissue scaffolding and as filtration membranes. Originality/value: At present, there are few articles in the literature on the electrospinning process, due to the fact that it is a constantly developing matte for the production of nanofibres. Moreover, most of the research focuses on fibres obtained from nonbiodegradable polymers, which do not have the advantages of fibres obtained from polylactide.

Wpływ kopalni węgla kamiennego na jakość wody rzeki Wisły

Policht-Latawiec A., Kapica A.

Rocznik Ochrona Środowiska

2013

Tom 15, cz. 3

2640--2651

The subject of the paper was determining the effect of supplied mine waters on the quality of the analyzed section of the Vistula River. “Silesia” Mine Enterprise (ME) which supplies the pollutants is situated in the southeastern part of the Śląskie province. Silesia ME extracts hard coal and mine gas – methane. The mine belongs to medium waterlogged mines with chloride-sodium inflowing waters. Before their discharge to the river, the mine waters are as a whole drained to the storage-dosing reservoir. Beside the retention and dosing mine waters to the Vistula River, the reservoir allows for removing the mechanical suspension from the waters.The main point of the work was acquisition of samples for analysis. Water samples were collected in 2011 from four control and measurement points along a kilometer section of the Vistula river and used for laboratory analyses. The control and measurement points were situated 20m above the discharge ditch outlet to the Vistula River and subsequently 50 and 1000 m below the discharge. The following parameters were measured immediately after water sampling: water temperature, the contents of dissolved oxygen, oxygenation capacity, pH and electrolytic conductivity. The other eighteen components were analyzed in a laboratory. Determined were: the content of total suspended solids, dissolved substances, sulphates, phosphates, total phosphorus, ammonium nitrogen, nitrite nitrogen, nitrites, nitrate nitrogen, nitrates, ammonium ion, chlorides, sodium, calcium, magnesium, total iron, potassium and manganese. The paper assessed the dynamics of water physicochemical indices, fulfilling conditions at supplying polluted water to the receiving water and functional values of water. It was stated that the Vistula waters deteriorate after introducing mine waters. They become waters below the good state, creating conditions unsuitable for fish life and unfit for water supply to people. Pollution of mine waters, regarded as treated sewage, exceeds the permissible values of some indices as stated in legal regulations. However, the key concentration of chlorides at the point of full mixing does not exceed their permissible values. River self-purification is on a good level, since mostly pollutant concentrations decrease on the length of the investigated section of the Vistula River, i.e. in point 4.