Viscometric study of chitosan solutions in acetic acid/sodium acetate and acetic acid/sodium chloride.
A viscometric study was carried out at 25°C to assess the physical-chemical behavior in solution and the mean viscometric molar mass (M¯v) of chitosan solutions with different deacetylation degrees, in two solvent mixtures: medium 1-acetic acid 0.3mol/L and sodium acetate 0.2mol/L; and medium 2-acetic acid 0.1mol/L and sodium chloride 0.2mol/L. Different equations were employed, by graphical extrapolation, to calculate the intrinsic viscosities [η] and the viscometric constants, to reveal the solvent's quality: Huggins (H), Kraemer (K) and Schulz-Blaschke (SB). For single-point determination, the equations used were SB, Solomon-Ciuta (SC) and Deb-Chanterjee (DC), resulting in a faster form of analysis. The values of ̄M¯v were calculated by applying the equation of Mark-Houwink-Sakurada. The SB and SC equations were most suitable for single-point determination of [η] and ̄M¯v and the Schulz-Blachke constant (kSB), equal to 0.28, already utilized for various systems, can also be employed to analyze chitosan solutions under the conditions studied.
Universidade do Estado do Rio de Janeiro, Instituto de Química, R. São Francisco Xavier, 524, Maracanã, 20550-900 Rio de Janeiro, RJ, Brazil.
Cristiane N
CN
Costa
Universidade Federal do Rio de Janeiro, Instituto de Química, Av. Athos da Silveira Ramos, 149, 21941-909, Rio de Janeiro, RJ, Brazil.
Viviane G
VG
Teixeira
Universidade do Estado do Rio de Janeiro, Instituto de Química, R. São Francisco Xavier, 524, Maracanã, 20550-900 Rio de Janeiro, RJ, Brazil.
Marcia C
MC
Delpech
Universidade do Estado do Rio de Janeiro, Instituto de Química, R. São Francisco Xavier, 524, Maracanã, 20550-900 Rio de Janeiro, RJ, Brazil.
Josefa Virginia S
JV
Souza
Universidade do Estado do Rio de Janeiro, Instituto de Química, R. São Francisco Xavier, 524, Maracanã, 20550-900 Rio de Janeiro, RJ, Brazil. Electronic address: marcos.costa@uerj.br.
Marcos A S
MA
Costa
Chitosan; Molecular weight determination; Single-point determination; Solvent quality