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Synthesis and characterization of multiwalled CNT-PAN based composite carbon nanofibers via electrospinning.

Kaur N, Kumar V, Dhakate SR - Springerplus (2016)

Bottom Line: Also with stabilization, carbonization and graphitization diameter of nanofiber decreases.XRD results show that degree of graphitization increases on increasing CNT concentration because of additional stresses exerting on the nanofiber surface in the immediate vicinity of CNTs.TGA results shows wt loss decreases as CNT concentration increases in fibers.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Krishna Institute of Engineering and Technology, Ghaziabad, India.

ABSTRACT
Electrospun fibrous membranes find place in diverse applications like sensors, filters, fuel cell membranes, scaffolds for tissue engineering, organic electronics etc. The objectives of present work are to electrospun polyacrylonitrile (PAN) nanofibers and PAN-CNT nanocomposite nanofibers and convert into carbon nanofiber and carbon-CNT composite nanofiber. The work was divided into two parts, development of nanofibers and composite nanofiber. The PAN nanofibers were produced from 9 wt% PAN solution by electrospinning technique. In another case PAN-CNT composite nanofibers were developed from different concentrations of MWCNTs (1-3 wt%) in 9 wt% PAN solution by electrospinning. Both types of nanofibers were undergone through oxidation, stabilization, carbonization and graphitization. At each stage of processing of carbon and carbon-CNT composite nanofibers were characterized by SEM, AFM, TGA and XRD. It was observed that diameter of nanofiber varies with processing parameters such as applied voltage tip to collector distance, flow rate of solution and polymer concentrations etc. while in case of PAN-CNT composite nanofiber diameter decreases with increasing concentration of CNT in PAN solution. Also with stabilization, carbonization and graphitization diameter of nanofiber decreases. SEM images shows that the minimum fiber diameter in case of 3 wt% of CNT solution because as viscosity increases it reduces the phase separation of PAN and solvent and as a consequence increases in the fiber diameter. AFM images shows that surface of film is irregular which give idea about mat type orientation of fibers. XRD results show that degree of graphitization increases on increasing CNT concentration because of additional stresses exerting on the nanofiber surface in the immediate vicinity of CNTs. TGA results shows wt loss decreases as CNT concentration increases in fibers.

No MeSH data available.


Related in: MedlinePlus

AFM images of PAN–CNT carbonized from concentration 3 wt% of CNT, tip to collector distance 10 cm, drum speed 2000 rpm, a 2D image, b 3D image
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Fig6: AFM images of PAN–CNT carbonized from concentration 3 wt% of CNT, tip to collector distance 10 cm, drum speed 2000 rpm, a 2D image, b 3D image

Mentions: Figure 5 shows 2D & 3D AFM images of PAN copolymer nanofibers mat of over an area 5 µm × 5 µm of concentration 9 wt% in DMF for nanofiber, stabilized nanofiber and carbonized nanofiber. This shows that nanofibers are randomly oriented and surface roughness of film is 32.3 nm. The surface area of film is 23 µm2 and from bar analysis of surface of film, nanofibers have diameter in the range 75–100 nm & depth of film is 273 nm (Ramakrishna et al. 2005; Samatham et al. 2006). But on carbonization, surface area decreases to 22.4 µm2 and surface roughness to 27.0 nm. The depth of film also decreases to 268 nm and fiber diameter to 70–90 nm. The change in depth and diameter is related to shrinkage of fiber film due to cyclization reactions take place at higher temperature. Figure 6 shows the AFM images of PAN–CNT 3 wt% carbonized fibers shows two kinds of regions, lighter and darker. The lighter regions are related to the highest points, and the darker regions are related to pores and valleys. This suggests that surface of film become more asymmetric on carbonization sharp spike in the picture is due to non orientation of fibre surface in one plane. It shows that surface of film is irregular which give idea about mat type orientation of fibers and high percentage of CNT was easily seen from fibre sheet which has darker black color. Diameter of fibre decreases due to presence of embedded CNT’s because diameter of Taylor cone is reduced due to high electron density. In carbonization there occur the change in depth and diameter due to shrinkage of fiber film due to cyclization reactions take place at higher temperature (Ko et al. 2003; Hendricks et al. 1964; Taylor 1969).Fig. 5


Synthesis and characterization of multiwalled CNT-PAN based composite carbon nanofibers via electrospinning.

Kaur N, Kumar V, Dhakate SR - Springerplus (2016)

AFM images of PAN–CNT carbonized from concentration 3 wt% of CNT, tip to collector distance 10 cm, drum speed 2000 rpm, a 2D image, b 3D image
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837748&req=5

Fig6: AFM images of PAN–CNT carbonized from concentration 3 wt% of CNT, tip to collector distance 10 cm, drum speed 2000 rpm, a 2D image, b 3D image
Mentions: Figure 5 shows 2D & 3D AFM images of PAN copolymer nanofibers mat of over an area 5 µm × 5 µm of concentration 9 wt% in DMF for nanofiber, stabilized nanofiber and carbonized nanofiber. This shows that nanofibers are randomly oriented and surface roughness of film is 32.3 nm. The surface area of film is 23 µm2 and from bar analysis of surface of film, nanofibers have diameter in the range 75–100 nm & depth of film is 273 nm (Ramakrishna et al. 2005; Samatham et al. 2006). But on carbonization, surface area decreases to 22.4 µm2 and surface roughness to 27.0 nm. The depth of film also decreases to 268 nm and fiber diameter to 70–90 nm. The change in depth and diameter is related to shrinkage of fiber film due to cyclization reactions take place at higher temperature. Figure 6 shows the AFM images of PAN–CNT 3 wt% carbonized fibers shows two kinds of regions, lighter and darker. The lighter regions are related to the highest points, and the darker regions are related to pores and valleys. This suggests that surface of film become more asymmetric on carbonization sharp spike in the picture is due to non orientation of fibre surface in one plane. It shows that surface of film is irregular which give idea about mat type orientation of fibers and high percentage of CNT was easily seen from fibre sheet which has darker black color. Diameter of fibre decreases due to presence of embedded CNT’s because diameter of Taylor cone is reduced due to high electron density. In carbonization there occur the change in depth and diameter due to shrinkage of fiber film due to cyclization reactions take place at higher temperature (Ko et al. 2003; Hendricks et al. 1964; Taylor 1969).Fig. 5

Bottom Line: Also with stabilization, carbonization and graphitization diameter of nanofiber decreases.XRD results show that degree of graphitization increases on increasing CNT concentration because of additional stresses exerting on the nanofiber surface in the immediate vicinity of CNTs.TGA results shows wt loss decreases as CNT concentration increases in fibers.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Krishna Institute of Engineering and Technology, Ghaziabad, India.

ABSTRACT
Electrospun fibrous membranes find place in diverse applications like sensors, filters, fuel cell membranes, scaffolds for tissue engineering, organic electronics etc. The objectives of present work are to electrospun polyacrylonitrile (PAN) nanofibers and PAN-CNT nanocomposite nanofibers and convert into carbon nanofiber and carbon-CNT composite nanofiber. The work was divided into two parts, development of nanofibers and composite nanofiber. The PAN nanofibers were produced from 9 wt% PAN solution by electrospinning technique. In another case PAN-CNT composite nanofibers were developed from different concentrations of MWCNTs (1-3 wt%) in 9 wt% PAN solution by electrospinning. Both types of nanofibers were undergone through oxidation, stabilization, carbonization and graphitization. At each stage of processing of carbon and carbon-CNT composite nanofibers were characterized by SEM, AFM, TGA and XRD. It was observed that diameter of nanofiber varies with processing parameters such as applied voltage tip to collector distance, flow rate of solution and polymer concentrations etc. while in case of PAN-CNT composite nanofiber diameter decreases with increasing concentration of CNT in PAN solution. Also with stabilization, carbonization and graphitization diameter of nanofiber decreases. SEM images shows that the minimum fiber diameter in case of 3 wt% of CNT solution because as viscosity increases it reduces the phase separation of PAN and solvent and as a consequence increases in the fiber diameter. AFM images shows that surface of film is irregular which give idea about mat type orientation of fibers. XRD results show that degree of graphitization increases on increasing CNT concentration because of additional stresses exerting on the nanofiber surface in the immediate vicinity of CNTs. TGA results shows wt loss decreases as CNT concentration increases in fibers.

No MeSH data available.


Related in: MedlinePlus