1070-4272/04/7704-0639 C 2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 4, 2004, pp. 639!644. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 4, 2004,
Original Russian Text Copyright + 2004 by Sazanov, Nud’ga, Novoselova, Ugolkov, Fedorova, Kulikova, Gribanov.
AND POLYMERIC MATERIALS
Carbonization of Polyacrylonitrile Composites
with Nitrogen-containing Cellulose Derivatives
Yu. N. Sazanov, L. A. Nud’ga, A. V. Novoselova, V. L. Ugolkov,
G. N. Fedorova, E. M. Kulikova, and A. V. Gribanov
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Institute of Silicate Chemistry, Russian Academy of Sciences, St. Petersburg, Russia
Received February 18, 2004
Abstract-Thermal carbonization of nitrogen-containing cellulose derivatives (chitin, chitosan, cyanoethyl
chitosan, cyanoethyl cellulose, copolymers of allyl carboxymethyl cellulose with polyacrylonitrile) as models
of probable products of thermal reaction of cellulose with polyacrylonitrile was studied. The quantitative
characteristics of carbonization of the model compounds are influenced by the nitrile group.
Polycarylonitrile (PAN) and a number of cellulose
derivatives are the most widely used precursors of
carbonized products . Numerous materials based
on their carbonizates are commercially produced for
chemical industry, power engineering, and medicine.
It has been shown previously  that joint carbon-
ization of PAN with other nitrogen-containing poly-
mers, mainly with polyheterocycles, involves thermal
reactions between the starting macromolecules. In
various steps of these reactions, new compounds are
formed, whose carbonization yields products of a po-
lycarbon structure with a number of specific proper-
ties. An analysis of these thermal reactions revealed
a particular role of nitrogen atoms in formation of
the carbonizate structure in the initial step of the re-
actions of PAN with the polymers examined; nitrogen
atoms present in the starting polymers affect the prop-
erties of the final carbonization product . Since
these effects were mainly observed in reactions of
PAN with various nitrogen-containing polyhetero-
arylenes, we examined in this study thermochemical
reactions of PAN with nitrogen-containing polysac-
charides and their derivatives.
To record changes in the kinetics of thermal reac-
tions of the starting compounds depending on their
structure and ratio and on the heat treatment condi-
tions, we used various methods of thermal analysis in
the dynamic and isothermal modes in the temperature
range 2031000oC. The reaction products were studied
by elemental analysis, pyrolytic gas chromatography
(PGC), and spectroscopy.
As nitrogen-containing polysaccharides, we used
chitin (CT) and chitosan (CTS), substances with vir-
tually unlimited resources of raw materials, showing
much promise as precursors of carbonized products.
It should be noted that there are no papers focused on
the carbonization of CT and CTS, and also of their
blends with other compounds. Certain aspects of
thermal degradation of CT, CTS, and their blends with
other compounds were considered in ; accord-
ing to these papers, their degradation, as that of PAN,
involves formation of reactive intermediates which
can react by intra- and intermolecular pathways.
The goal of this study was to determine the condi-
tions and mechanism of carbonization of chitin and
chitosan and of their blends with PAN. CT and CTS
were prepared and pretreated according to [17, 18];
PAN was synthesized using radical (r-PAN) and ani-
onic (c-PAN) catalysts .
The kinetics of thermal degradation in a vacuum
was studied by thermovolumetric analysis (TVA); the
thermal oxidative degradation was monitored by TGA
and DTA. The results (Figs. 1, 2) show that the ther-
mal reactions are the most intense in the range 1503
Thermal degradation in a vacuum (Fig. 1, curve 1)
follows the mechanism of transformation of r-PAN
into the cyclic analog of PAN, considered in .
At 200oC, vigorous release of volatiles is observed,
with a maximum at 215oC and weight loss of 21.5%.
These products mainly consist of nitrogen-containing