Please use this identifier to cite or link to this item:
|Title:||Physicochemical characterization of thermally treated chitosans and chitosans obtained by alkaline deacetylation|
|Author:||de Oliveira, Ana Maria|
Franco, Telma Teixeira
de Oliveira Junior, Enio Nazare
|Abstract:||The thermal depolymerization of chitosan and alkaline deacetylation of chitin were characterized by measurement of viscosity, gel permeation chromatography (GPC), potentiometric titration (PT), and proton nuclear magnetic resonance spectroscopy (H-1 NMR). Thedepolymerization rates (DR) measured by kinematic viscosity (KV), apparent viscosity (AV), andGPC (Mw) until 4 h of treatment were DRKV = 21.9, DRAV = 25.5, and DRMw = 23.3% h(-1) and for 5 to 10 h of treatment they decreased slowly to produce of DRKV = 0.545, DRAV = 0.248, and DRMw = 1.11% h(-1). The mole fraction of N-acetylglucosamine residues (F-A) of chitosans was not modified after 10 h of thermal treatment at 100 degrees C. The initial F-A values of chitosan without any treatment were F-APT = 0.21 and F-A1HNMR = 0.22 and of chitosan treated for 10 h were F-APT = 0.27 and F-A1HNMR = 0.22. The variables used to characterize the depolymerization process showed a good correlation. Six hours of thermal treatment as sufficient to obtain chitosans with a molar mass 90% smaller than that of the control chitosan without treatment|
|Appears in Collections:||FEQ - Artigos e Outros Documentos|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.