Author, Institution: Jurgita Šateikė, Kaunas University of Technology
Science area, field of science: Technological Sciences, Materials Engineering (T008)
Scientific Supervisor: Prof. Dr. Rimvydas Milašius (Kaunas University of Technology, Technological Sciences, Materials Engineering – T008).
Dissertation Defence Board of Materials Engineering Science Field:
Prof. Dr. Daiva Mikučionienė (Kaunas University of Technology, Technological Sciences, Materials Engineering – T008) – chairwoman;
Prof. Dr. Juris Blums (Riga Technical University, Technological Sciences, Materials Engineering – T008);
Dr. Sigitas Krauledas (Center for Physical Sciences and Technology, Technological Sciences, Materials Engineering – T008);
Prof. Dr. Jolita Ostrauskaitė (Kaunas University of Technology, Technological Sciences, Materials Engineering – T008);
Prof. Dr. Sigitas Stanys (Kaunas University of Technology, Technological Sciences, Materials Engineering – T008).
The doctoral dissertation is available at the library of Kaunas University of Technology (Donelaičio 20, Kaunas).
Starch was the main objective of this dissertation. In order to achieve the improvement of electrospinnability and formed nano-micro size fibres, starch was cationically modified and mixed with synthetic polymer. Poly(vinyl alcohol) PVA is one of the most widely used synthetic polymers and has a great interest due to its positive properties suitable for pharmaceutical, biomedical applications. However, one of the most important advantages of this synthetic polymer is its relatively low cost. Thus, the economic aspect can be one of the many other benefits of this synthetic polymer.
Starch is a polysaccharide that has a property with good iodine absorption, which can be an excellent antiseptic with antimicrobial properties and is widely used in the treatment of wounds. However, starch has its chemical nature that complicates the electric spinning process. In order to improve the electrospinning process of this polysaccharide, it can be blended with synthetic polymers, which have good properties for the nano-microfibre formation. The doctoral dissertation analysed and investigated the influence of natural and cationic starch on the process of electrospinning and on the structure and morphology of the formed fibres.
The fibre web was electrospun by using the NanospiderTM (Germany) electrospinning equipment. The fibres that were manufactured in this equipment used two different kinds of rotating electrode: cylindrical and electrode with the tines. The rotating electrode is partially immersed in a tray with polymer solution, towards the upper electrode, which is attached to the collection part.
Scanning Electron Microscopy (SEM) with SEM-FEI Quanta 200 (The Netherlands) was used to observe and identify the morphology and structure of nonwoven material from nano-microfibres. A small section of the nano-microfibre mat was used in SEM with the use to determine the morphology of nano-microfibres. Lucia 5.0 software was utilized to measure the diameter of nano-microfibres and calculate the average diameters of the observed fibres.
In this doctoral dissertation, fibres from mixtures of PVA and natural starch solutions were formed by electrospinning method, when the potato starch content in PVA spinning solution (1, 3 and 5%). The influence of a small amount of ethanol (1, 3, 5 %) on the process of electric spinning and on the structure and morphology of the formed fibres was also analyzed. A series of tests was performed with PVA and cationic starch KOEK at a weight ratio of 75/25, 50/50 and 35/65 in the spinning solution. The influence of different concentrations of the formed fibres and the influence of low ethanol content (3, 6 and 9 %) on the morphology of the fibres structure and the electrospinning process were analyzed.
The dissertation proves that using electrospinning method, it is possible to form fibres from PVA and potato starch spinning solutions. The influence of ethanol on the electric spinning process and the morphology and structure of the formed filaments was investigated. The most suitable concentration of spinning solutions from PVA/KOEK was determined when the mass ratio was 75/25 and the most suitable rotating electrode type for the electrospinning process was selected and determined. In this work it was proved that it is possible to form fibres from PVA solution with 50 % and 65 % KOEK.