Limits...
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

SEM image PAN–CNT nanocomposite with 1 % MWCNTs
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4837748&req=5

Fig2: SEM image PAN–CNT nanocomposite with 1 % MWCNTs

Mentions: The concentration, viscosity, and conductivity of the solution as well as the applied voltage and distance between the charged electrode and the grounded target were adjusted in order to obtain stable electrospinning jet (Drozin 1955). Figure 1 shows the micrograph of electrospun nanofibers (Gupta and Wilkes 2003) prepared from solution of 9 wt% of PAN concentration with flow rate 0.2 ml/h and collector speed 1000 rpm, applied voltage 15 kV in which tip to collector distance varies from 10 to 20 cm at EHT = 10 kV and at different magnification. It is observed that with increasing the tip to collector distance, fiber diameter decreases. At tip to collector distance 10 cm, fiber diameter is in the range of 100–175 nm and decreases to 75–175 nm on increasing distance to 15 cm. In this case the variation is comparatively less as compared to tip to collector distance 10 cm. This variation in diameter is due to the instability in jet due to change in repulsive forces (Baumgarten 1971). Figure 2 shows the SEM image of PAN–CNT composite with 1 % MWCNTs. The CNTs are aligned in nanocomposite, which is distinguished by color of PAN nanofibers. The presence of black color in fiber, it indicates the presence of CNTs in nanofibers. Since the MWNTs possess a high electron density compared with the PAN polymer matrix, the nanotubes appear as darker tubular structures embedded in the PAN distorted nanofibers with black impression. The stabilization is one of the important steps and play important role in controlling the properties of final fibers (Ramakrishna et al. 2005; Ko et al. 2003; Khil et al. 2005). Figure 3 shows the stabilized PAN–CNT 3 wt% nanofibers. The oxidative stabilization was carried out at 310 °C and kept isothermally for 1 h. It is found that, on stabilization fibers diameter decreases as compared as spun nanofiber diameter. Figure 4 shows the SEM image of carbonized fiber with 3 wt% of CNTs incorporated during the processing. From the figure it is observed that there visible difference in the morphology of carbon-CNT composite nanofibers. At higher content of CNTs, CNTs are might be not individually aligned during electrospinning. Therefore, from the surface of carbon-CNTs nanofiber, it is visible bundles (He et al. 2004) in the range of 50–100 nm in the fiber of diameter 300–400 nm (Guo et al. 1955).Fig. 1


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

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

SEM image PAN–CNT nanocomposite with 1 % MWCNTs
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig2: SEM image PAN–CNT nanocomposite with 1 % MWCNTs
Mentions: The concentration, viscosity, and conductivity of the solution as well as the applied voltage and distance between the charged electrode and the grounded target were adjusted in order to obtain stable electrospinning jet (Drozin 1955). Figure 1 shows the micrograph of electrospun nanofibers (Gupta and Wilkes 2003) prepared from solution of 9 wt% of PAN concentration with flow rate 0.2 ml/h and collector speed 1000 rpm, applied voltage 15 kV in which tip to collector distance varies from 10 to 20 cm at EHT = 10 kV and at different magnification. It is observed that with increasing the tip to collector distance, fiber diameter decreases. At tip to collector distance 10 cm, fiber diameter is in the range of 100–175 nm and decreases to 75–175 nm on increasing distance to 15 cm. In this case the variation is comparatively less as compared to tip to collector distance 10 cm. This variation in diameter is due to the instability in jet due to change in repulsive forces (Baumgarten 1971). Figure 2 shows the SEM image of PAN–CNT composite with 1 % MWCNTs. The CNTs are aligned in nanocomposite, which is distinguished by color of PAN nanofibers. The presence of black color in fiber, it indicates the presence of CNTs in nanofibers. Since the MWNTs possess a high electron density compared with the PAN polymer matrix, the nanotubes appear as darker tubular structures embedded in the PAN distorted nanofibers with black impression. The stabilization is one of the important steps and play important role in controlling the properties of final fibers (Ramakrishna et al. 2005; Ko et al. 2003; Khil et al. 2005). Figure 3 shows the stabilized PAN–CNT 3 wt% nanofibers. The oxidative stabilization was carried out at 310 °C and kept isothermally for 1 h. It is found that, on stabilization fibers diameter decreases as compared as spun nanofiber diameter. Figure 4 shows the SEM image of carbonized fiber with 3 wt% of CNTs incorporated during the processing. From the figure it is observed that there visible difference in the morphology of carbon-CNT composite nanofibers. At higher content of CNTs, CNTs are might be not individually aligned during electrospinning. Therefore, from the surface of carbon-CNTs nanofiber, it is visible bundles (He et al. 2004) in the range of 50–100 nm in the fiber of diameter 300–400 nm (Guo et al. 1955).Fig. 1

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