컨베이어 벨트 타입 전기방사기를 통해 제조된 TEOS/PVP 실리카 나노-웹의 형태학적, 열적 특성

초록

Fine dust is a primary cause of air pollution, and to prevent this issue, silica web filters have been utilized to measure fine dust. The fabrication of these silica web filters involves wet-laid nonwoven methods and electrospinning techniques. However, when tetraethyl orthosilicate (TEOS)/polyvinylpyrrolidone (PVP) silica nano-webs are manufactured using these methods, limitations arise in terms of productivity due to the batch-based process and the implementation of continuous fibers. In particular, the wet-laid nonwoven method has a drawback in that it cannot control the pore size, which determines the filter's performance. Therefore, this study aimed to address issues related to pore size control and product scalability by manufacturing TEOS/PVP silica nano-web using a newly conceptualized conveyor belt-type electrospinning apparatus. During the preparation of the TEOS/PVP solution, stirring for more than three hours facilitated hydrolysis and condensation reactions. It was observed that nanofibers with diameters ranging from approximately 100 nm to 1000 nm were formed successfully when the TEOS content was 13 wt.%, 18 wt.%, and 24 wt.%. Also, the formation of bead varies depending on the viscosity of the solution and the degree of hydrolysis and condensation reactions. Silica nanowebs produced with the lowest TEOS content of 8 wt.% failed to form continuous fibers and were instead deposited as powder on the belt. Conversely, silica nanowebs produced with the highest TEOS content of 30 wt.% exhibited beads along with fibers within the web structure due to the high viscosity of the TEOS/PVP spinning solution. The thermal properties and morphological properties of the silica nanowebs were analyzed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and optical microscope (OM). It was observed that the silica nanowebs exhibited excellent thermal properties and morphological properties reflecting the inherent characteristics of silica fibers.

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