Autori: S. Coseri, G. Nistor, L. Fras, S. Strnad, V. Harabagiu, B.C. Simionescu

Editorial: Biomacromolecules, 10(8):, p.2294-9 , 2009.

Rezumat:

The oxidation reaction of regenerated cellulose fibers mediated by N-hydroxyphtalimide (NHPI) and
various cocatalysts at room temperature for different time intervals and various amounts of low
concentration sodium hypochlorite solution has been investigated to produce oxidized cellulose (OC), a
biocompatible and bioresorbable polymer. The results revealed that the non persistent phthalimide-Noxyl
(PINO) radical generated in situ from NHPI in both, metallic or metal-free systems, is a powerful
agent in this kind of transformations. Moreover, the reaction occurs highly selective at C6 primary
hydroxyl groups to carboxylic groups, under mild reaction conditions and shorter reaction times than
previously reported. The amounts of negatively charged groups in OC were determined by means of
potentiometric titration, further characterization of resulted products by using Fourier transform infrared
spectroscopy/attenuated total internal reflection spectroscopy (FT-IR/ATR), Environmental Scanning
Electron Microscopy (ESEM), X-Ray and Energy-Dispersive X-ray (EDX) spectroscopy have been
carried out. Notably, water retention values of the oxidized fibers increased by 30 % in comparison with
the original non-oxidized sample, as a result of the introduction of hydrophilic carboxylate groups.

Cuvinte cheie: cellulose fibers, oxidation, surface modification, N-hydroxyphthalimide, phthalimide-Noxyl