Date

2018

Author

Şahin, Selin

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Electrospinning is a very simple and efficient method in production of nanofibers with high surface area/volume ratio, thus has significant potential in developing the nanotechnology. The nano-scale fibers and the interactions in nano level among components of the fibers ensure composite nanofibers to be a promising field of research. In this study, optimization of the electrospinning parameters for neat Polyamide-6 (PA6) nanofiber production and investigation on performance of composite nanofibers containing Halloysite Nanotubes (HNTs) were aimed. Firstly, neat PA6 nanofibers were produced by changing the solution concentration, solvent type, applied voltage, solution feed rate and tip-to-collector distance. Simultaneously, the PA6 composite nanofibers with unmodified and modified HNTs (m-HNTs) were prepared and characterized using SEM, TGA, DSC analyses and tensile tests. Also, degradation tests under chemical vapors and a flame retardancy test were performed on some selected samples. Results revealed that the addition of 1 wt.% m-HNTs to PA6 increased the tensile modulus of the neat PA6 nanofiber mat by 25% and provided uniform fiber morphology and constant thermal properties. In degradation test, the neat PA6 and the nanofiber mat containing 1 and 8 wt.% m-HNTs were subjected to HCl, acetone, toluene and water vapors. After HCl and water vapor exposure, decrease in thermal and mechanical properties were observed together with significant change in morphology. Chemical degradation was slightly prevented by the addition of 1 wt.% m-HNTs. Diffusion coefficients of the thin nanofiber mats exposed to these chemical vapors were determined to be in the order of 10-15 m2/s. LOI tests were applied to both electrospun mats and compression molded films to determine flame retardant properties. While compression molded PA6 films had a LOI value of 27% O2, the LOI value of the electrospun PA6 mat was found as 31% O2. This revealed the positive effect of orientation and the porous structure of the nanofibers on the flame retardant properties.

Subject Keywords

Nanocomposites (Materials)., Polyamide fibers., Electrospinning., Nanotubes.

URI

http://etd.lib.metu.edu.tr/upload/12622888/index.pdf
https://hdl.handle.net/11511/27869

Collections

Graduate School of Natural and Applied Sciences, Thesis