Poster presentation
307
ELECTROSPINNING OF NANOFIBERS FROM Bombyx mori
CHITOSAN SOLUTIONS
R.Yu. Milusheva, K.K. Pirniyazov, S.Sh. Rashidova
Institute of Polymer Chemistry and Physics of ASRU, Tashkent, Kadyri St., 7, b
The development of functional materials from renewable sources (silk production
waste) is an urgent task. The production of nanofibers based on chitosan is a new
direction in the field of nanotechnology, since their production differs significantly in
key parameters. Different feedstocks (chitosans from heterogeneous sources) lead to
spinning solutions with different characteristics, which naturally leads to differences in
the resulting nonwoven nanofiber materials.
The electrospinning of nanofibers was carried out on an ES-robot Electrospinning
/spray system with chitosan solutions of various concentrations. The electric field
voltage was 25–28 W, the distance between the anode and cathode was 10 cm. The
solution supply rate was controlled in the range from 2 to 20 μl/min. To obtain
nanofibers, purified chitosan was obtained of preliminary dissolution of chitosan in 2%
acetic acid, precipitation and coagulation of the solution at a certain pH, washing with
alcohol, centrifugation, and freeze-drying of the sample.
A sample of purified chitosan with Mv 184 kDa and SDA=84% was obtained. Bombyx
mori solutions of various concentrations of chitosan in 80% acetic acid were prepared for
electrospinning. IR spectroscopic and X-ray studies of the obtained nanofibers were carried
out (Fig. 1,2).
Fig. 1. - IR spectra of chitosan Vm and
nanofibers based on it (Blue - nanofibers, red -
original)
Fig. 2. - Diffraction pattern of chitosan Vm and
nanofibers based on it (Blue - nanofibers, red -
original)
The IR-spectrum of nanofibers of chitosan Bm differs from the initial spectrum of chitosan
Bm, which may be due to the conditions for the formation of nanofibers, since during
electrospinning of chitosan solutions, orientation of macromolecules occurs. Changes in the
crystallinity and polymorphism of chitosan lead to slight differences in the absorption
intensity in the absorption bands at 1604 cm-1 and 1592 cm-1. In nanofibers, a narrower
absorption band at about 3500 cm–1 is observed, which confirms the partial participation of
hydroxyl groups in the C2 and C6 positions of chitosan in intra- and intermolecular hydrogen
bonds.The diffraction patterns of Bombyx mori chitosan show crystalline reflections with
maxima at 2θ=5.79o, 10.52o, 20.3o and 28.9o. At the value of the angle 2θ=20.3°, the most
intense maximum is observed, which refers to the crystallographic reflection (020). In this
case, an amorphous halo is observed in the diffraction patterns of nanofibers, as well as broad
crystalline reflections of the corresponding imperfect crystals. Thus, the IR and X-ray
diffraction patterns of the obtained samples unambiguously indicate the formation of
nanofibers under these conditions with the observed differences in the IR spectra and
diffraction patterns.
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