INTEC   05402
INSTITUTO DE DESARROLLO TECNOLOGICO PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
artículos
Título:
Rapid estimation of gamma number of viscose by UV spectrophotometry
Autor/es:
LANIERI D. B.; OLMOS G. V.; ALBERINI I. C.; MAXIMINO M. G.
Revista:
O PAPEL
Editorial:
Brazilian Technical Association of Pulp and Paper
Referencias:
Año: 2014 vol. 75 p. 60 - 65
ISSN:
0031-1057
Resumen:
Viscose process is the most important method for industrial
cellulose dissolution. The degree of substitution (DS) is an important
parameter in cellulose derivatives, and it is usually expressed as a
gamma number (γ number).
In this work, viscose was prepared from eucalyptus and cotton
linter dissolving pulps. Two methods were used for by-product
separation: coagulation method (CM, reference) and ion exchange
method (IEM). Similar γ Nos. were obtained with both methods for
viscoses from cotton linters.
The molar absorptivity of cellulose xanthate at 303 nm (absortivity at 303 nm)was determined by, firstly, measuring the absorbance of different
purified viscoses and, subsequently, drawing a linear regression
with the values obtained.
The purification efficacy of IEM was analyzed from the UV peaks
obtained in the range of 220-380 nm of the original and purified
viscoses. The disappearance of the absorption of the main byproduct,
sodium trithiocarbonate, was observed.
Finally, with the e303nm mentioned above and the absorbance
measurement of the purified viscoses, their γ Numbers. were determined
using a spectrophotometric method (SM). This would indicate that
UV spectrophotometry could be used to estimate this parameter
in a quick and easy way, which is decisive for the use of viscose in
regenerated cellulose products.