1070-4272/05/7807-1182+2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 7, 2005, pp. 1182!1184. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 7,
2005, pp. 1203!1205.
Original Russian Text Copyright + 2005 by Osovskaya, Poltoratskii, Dmitrieva, Kamyshanskaya.
AND POLYMERIC MATERIALS
Hydrophilic Characteristics of Cellulose Treated
with Saturated Water Vapor
I. I. Osovskaya, G. M. Poltoratskii, E. A. Dmitrieva, and Ya. V. Kamyshanskaya
St. Petersburg State Technological University of Plant Polymers, St. Petersburg, Russia
Received November 2, 2004; in final form, March 2005
Abstract-The reaction of water with cellulose treated with saturated water vapor at various temperatures for
various times was studied. Trends in variation of its sorption and hydrophilic characteristics were examined.
The system of hydrogen bonds, macromolecular
mobility, and regularity in arrangement of macro-
molecules in cellulose can be varied by physical or
chemical actions . One of the ways is treatment
of cellulose with saturated water vapor. Sorption of
water vapor with cellulose at various temperatures
was considered previously [6, 7]. However, the influ-
ence of conditions of cellulose treatment with satu-
rated water vapor on its physicochemical character-
istics remains poorly understood, although such a
treatment of dry cellulose material can be used in
preparation of cellulose for chemical processing and
paper production .
Formation of hydrogen bonds of water molecules
with active groups of the polymer in this treatment
and also partial breakdown of the system of intra-
molecular and intermolecular hydrogen bonds in the
glassy component of cellulose affect subsequent sorp-
tion activity and reaction of the treated polymer
Therefore, the goal of this study is a search for
optimal conditions of cellulose treatment with satu-
rated water vapor to restore its capillary-porous struc-
ture lost under drying in production of pulp.
We mainly used thermodynamic methods reflecting
sorption and energy characteristics of cellulose fibers.
Absorption of water with cellulose from liquid and
gas phases was monitored from the enthalpy of wet-
ting and desorption isotherms; variation of the internal
surface area was characterized by sorption of a dye.
Kraft whitened cellulose (SP-1650, degree of order-
ing 0.65, a-cellulose content 95.5%) was the subject
of the study. The degree of polymerization was deter-
mined viscometrically at 298 K. Sodium ferric tartrate
complex was used as a solvent. The degree of order-
ing was determined by X-ray diffraction analysis, and
a-cellulose content, by dissolution of cellulose in
17.5% aqueous NaOH. The industrial samples of air-
dry cellulose were treated under conditions of constant
100% relative humidity at temperatures T of 353, 373,
and 438 K for the time t from 3 to 15 min. Dehydra-
tion of the samples for calorimetric measurements and
the study of dye sorption were performed by the in-
clusion method. Recording of desorption isotherms
did not require additional treatment of the samples.
The thermal effects of the interaction of cellu-
lose with water DH were obtained on a calorimeter
equipped with an isothermal shell; the average relative
error was +1%. The desorption isotherms of water
Table 1. Heat of cellulose wetting
³Conditions of treatment with water vapor³
³ T,K ³ J, min ³
1* ³ ! ³ ! ³ 49.0
2 ³ 438 ³ 3 ³ 70.6
3 ³ 438 ³ 5 ³ 84
4 ³ 438 ³ 7 ³ 70.2
5 ³ 438 ³ 10 ³ 60.2
6 ³ 373 ³ 5 ³ 60.2
7 ³ 373 ³ 10 ³ 70
8 ³ 373 ³ 15 ³ 54.4
9 ³ 353 ³ 5 ³ 53.8
10 ³ 353 ³ 10 ³ 64.2
11 ³ 353 ³ 15 ³ 68.8
12** ³ ! ³ ! ³ 84.8
* Initial cellulose.
** Non-dried cellulose.