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wizyta

od 2020-09-20

Mgr Alovidin Nazirov  | 2000-10 <> 2005-07

Doktorant


Zainteresowania naukowe:
Badanie dynamiki molekularnej biokopolimerów metodami NMR

Publikacje                          Seminaria


2.

Nozirov F., Fojud Z., Jancelewicz M., Nazirov A., Jurga S.

Molecular motion in the biocopolymer sequence of glycolide and lactide studied by solid state NMR This paper reports a nuclear magnetic resonance study of the molecular motion in copolymers derived from glycolide and L-lactide in the solid state. Variation of T-1 relaxation times with temperature reflects a local disorder and the fast segment conformational motions which can be quantified in terms of correlation times predicted by the Bloembergen-Purcell-Pound and Davidson-Cole models. At low temperatures, spin relaxation is dominated by the axial methyl rotation in lactide units described by an asymmetry parameter of the correlation time delta which takes a value of about 0.45 for all systems. Above the devitrification points the trans and gauche isomerization in glycolide segments occurs. In addition to the chemical structure characterization, solid-state magic-angle spinning spectroscopy gives an insight into the role of glycol segments in the chain mobility.

Applied Magnetic Resonance, 34(1-2), 193-203 (2008)

DOI: 10.1007/s00723-008-0102-z   (Pobrane:  2020-10-23)


1.

Nozirov F., Nazirov A., Jurga S., Fu R.

Molecular dynamics of poly(L-lactide) biopolymer studied by wide-line solid-state 1H and 2H NMR spectroscopy The molecular dynamics of poly(L-lactide) (PLLA) biopolytner was characterized through analyses of H-1 and H-2 NMR line-shapes and spin-lattice relaxation times at different temperatures. At low temperatures (e.g. 90K), the methyl group rotation is dominant leading to a significant reduction in the proton second moment. Fast methyl group reorientation occurs at ca. 130 K. In additional to the fast methyl group rotation, hydroxyl groups start to reorient as the temperature increases further, eventually leading to the breakdown of the segments of the biopolymer chains above its glass transition temperature Tg of 323K. The analyses of the H-2 NMR line-shapes indicate that both the methyl and hydroxyl reorientations can be described by the so-called cone model, in which the former has three equilibrium positions with theta(C-D) = 70.5 degrees and phi = 120 degrees while the latter one exhibits two equilibrium positions with theta(C-D) = 78 degrees and phi = 180 degrees.
(C) 2005 Elsevier Inc. All rights reserved.

Solid State Nuclear Magnetic Resonance, 29(4), 258-266 (2006)

DOI: 10.1016/j.ssnmr.2005.09.001   (Pobrane:  2020-10-21)


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