1. ELECTROSPINNING OF LIGAND DOPED NANOFIBERS
Ramazan Erdem1, Özlem Erdem2, Onur Atak3 and Abdulkadir Pars3
1Department of Textile Technologies, Serik G. S. Süral Vocational School of Higher Education, Akdeniz University, 07500, Antalya, Turkey
2Department of Textile Technology, Adana Vocational School of Higher Education,Cukurova University, 01330, Adana, Turkey
3 Department of Textile Engineering, Technology Faculty, Marmara University, 34722, Istanbul, Turkey
ABSTRACT
Chiral binaphthyl Schiff base ligand was prepared by condensation of 2,2-diamino-1,1-binaphthalene with 2-hydroxy-3-methoxybenzaldehyde. The synthesized ligand were characterized by elemental analysis, FT-IR, 1H NMR UV–vis spectroscopy. Synthesized ligand compound was added into polyurethane fibers by electrospinning process. Properties of the blended solutions were analyzed in terms of viscosity and conductivity. The morphology of nanofibrous membranes were observed by SEM analysis. Diameter of the nanofibers was recorded in the range between 520 nm and 730 nm, respectively.
EXPERİMENTAL PROCEDURE
1.Synthesis and Characterization of Ligand Compound
3. Electrospinning Process
Each solution was placed in a plastic syringe and sent to the drum collector (covered with oil paper) through a 20 gauge nozzle. Three different nanofibrous webs were fabricated through two types of electrospinning machines. Table 2 presents the details of the process conditions of each specimen. Rotational speed of the drum collector was 100 rpm/min and its distance was set to 25–32 cm away from the nozzle.
Table 2 Electrospinning parameters.
Polymers
Feeding Rate (ml/h)
AppliedVoltage (kV)
Distance (cm)
Fed Solution (ml)
Machine Type
PU (%10wt.)
1.5
34.5 25 3
NSLab24, NanoFMG
PU+0.015g LIG
3.8 32
2.5
NE200,
Inovenso
PU+0.050g LIG
Fig 1. Synthesis of the Ligand
Elemental Anal. (C, H and N, wt.%) Calc. for C36H28N2O4: C, 78.24; H, 5.11; N, Found: C, 78.29; H, 4.78; N, %. IR (KBr, cm-1): , OH; 3055, Ar-H; 2935, 2832, C-H(O-CH3); 1607,1623, C-H(imine); 1575,1588 C=C(Ar). 1H NMR (400 MHz, CDCl3, d: ppm): ) δ= (s, 2H, OH), 8.61 (s, 2H, CH=N), 8.09 (d, J=8 Hz, 2H, Ph-H), 7.96 (d, J=8 Hz, 2H, Ph-H), 7.61 (d, J=9 Hz, 2H, naftil-H), 7.46 (q, 2H, naftil-H), 7.26 (m, 2H, Ph-H), 7.22 (d, J=8 Hz, naftil-H), 6.87 (m, 4H, naftil-H), 6.79 (m, 2H, naftil-H), 3.82 (s, 6H, O-CH3). [a] D 20: -220 deg cm2 g-1.
4. Morphology of the Nanofibrous Scaffolds
SEM micrographs exhibited that nanofibers were distributed randomly within the scaffolds and very porous 3D structures were established (Figure 4).The diameter of pure PU nanofibers was around 730±322 nm and that of LIG incorporated ones were 520±234 and 704±250, subsequently. It was clearly observed that fiber diameters were noticeably influenced by solution properties such as conductivity and viscosity. Also, different electrospinning machines required different setting parameters although the polymer solutions are the same in order to establish a stable fiber production. Therefore, fiber characteristics were also affected from the machine models.
Fig. 2. FTIR analysis of the Ligand.
Fig. 3. 1H NMR spectrum of the Ligand..
2. Solution Properties
In our study, viscosity and conductivity characteristics of the solutions made the electrospinning process smooth, and uniform fibers were obtained successfully. Table 1 represents the solution properties and related fiber diameters.
Table 1. Solution properties and related fiber diameters.
Polymer
Viscosity (cP)
Conductivity (μS/cm)
Fiber Diameter (nm)
PU (%10wt.)
105
2.7
730±322
PU+0.015g LIG
120
2.2
520±234
126.5
1.8
704±250
According to the table, viscosities of PU solutions increased noticeably with the addition of LIG into the blends from 105 cP to cP. This is most probably due to the increase in the amount of the molecules in the solution. On the other hand, solution conductivity declined from 2.7μS/cm to 1.8μS/cm with the introduction of LİG into the blends. This may be associated with the chemical bonding between LiG and the PU polymer.
Fig. 4. SEM pictures of nanofibers: (A) Pure PU nanofibers, (B) 0.015g LIG 2 doped PU nanofibers, (C) 0.050g LIG doped PU nanofibers.
CONCLUSION
Pure PU and LIG doped PU nanofibers have been successfully fabricated. Electrospinning solution properties (conductivity and viscosity, process parameters and machine types were noticeably influent on the fiber morphology and diameters. This experimental work showed that incorporation of different additives into the polymer fibers can establish novel functional nanofibrous webs through electrospinning.
ACKNOWLEDGEMENTS
The authors would like to thank Akdeniz, Marmara, Cukurova Universities for their financial supports.
Conference on Value Addition and Innovation in Textiles, COVITEX, PAKİSTAN,2017