Electrospun polyamide-6 and polyamide-6/halloysite nanotubes composite nanofibers: parameter optimization and characterization

Şahin, Selin
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.


Elektro-eğirme Yöntemi Kullanılarak Üretilen Naylon-6/Haloysit Nanotüp Nanofiberlerinin Çoklu Fonksiyonel Özelliklerinin Geliştirilmesi
Bayram, Göknur(2018)
Elektro-eğirme yöntemi günümüz teknolojisinin geliştirilmesinde önemli potansiyele sahip olanyüksek boy/çap oranındaki nanofiberlerinin üretiminde kullanılan oldukça verimli biryöntemdir. Üretilen fiberlerin nano boyutta olması ve yapıya eklenen katkı malzemesi ile nanodüzeyde etkileşime geçmesi kompozit nanofiberlerinin gelecek vaat eden konulardan biriolmasını sağlamaktadır.Bu çalışmada elektro-eğirme yönteminde kullanılan proses parametrelerinin optimize edilerekdüzgün Naylon-6 (PA6) nanofiber üretiminin...
Electrochemical Reduction of Tungsten Compounds to Produce Tungsten Powder
ERDOĞAN, METEHAN; Karakaya, İshak (Springer Science and Business Media LLC, 2010-08-01)
The production of tungsten by direct current reduction has been investigated. Experimental studies involved the electrochemical reduction of the solid tungsten compounds tungsten trioxide (WO(3)) and calcium tungstate (CaWO(4)) in the form of an assembled cathode of porous pellets attached to a current collector. Molten calcium chloride and a molten solution of calcium chloride and sodium chloride at eutectic composition, 48 pct mol NaCl, were used as the electrolytes. Reduced samples were characterized by ...
Electrospun multifunctional diclofenac sodium releasing nanoscaffold
Nikkola, L.; Seppala, J.; Harlin, A.; Ndreu, A.; Ashammakhi, N. (American Scientific Publishers, 2006-09-01)
Electrospinning is a method utilized to produce nano-scale fibers for tissue engineering applications. A variety of cells are attracted by nano scale surfaces and structures probably due to the similarity of their natural environment scale. In this study, diclofenac sodium (DS) releasing nanofibers; were manufactured via electrospinning process. Poly(95 epsilon-capro/5 D,L-lactide) was dissolved into acetic acid to form a 20% w/v solution. 2% w/w of DS was then added into the polymer solution and stirred ho...
Flame retardancy of polymer nanocomposites
Işıtman, Nihat Ali; Kaynak, Cevdet; Department of Metallurgical and Materials Engineering (2012)
This thesis is aimed to understand the role of nanofiller type, nanofiller dispersion, nanofiller geometry, and, presence of reinforcing fibers in flame retardancy of polymer nanocomposites. For this purpose, montmorillonite nanoclays, multi-walled carbon nanotubes, halloysite clay nanotubes and silica nanoparticles were used as nanofillers in polymeric matrices of poly (methyl methacrylate) (PMMA), high-impact polystyrene (HIPS), polylactide (PLA) and polyamide-6 (PA6) containing certain conventional flame...
Özerinç, Sezer (2018-12-01)
Nanoindentation is a widely used tool for probing the mechanical properties of materials at the nanoscale. The analysis of the load-displacement curve obtained from nanoindentation provides the hardness and elastic modulus of the material. While hardness is a useful parameter for comparing different alloys and understanding tribological behavior, yield strength is a more useful parameter for alloy design and application in general. The yield strength of a nanoindentation-tested material can be estimated by ...
Citation Formats
S. Şahin, “Electrospun polyamide-6 and polyamide-6/halloysite nanotubes composite nanofibers: parameter optimization and characterization,” M.S. - Master of Science, Middle East Technical University, 2018.