ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 4, pp. 619!622. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + Yu.N. Sazanov, G.N. Fedorova, E.M. Kulikova, D.M. Kostycheva, A.V. Novoselova, A.V. Gribanov, 2007, published in Zhurnal
Prikladnoi Khimii, 2007, Vol. 80, No. 4, pp. 632! 636.
AND POLYMERIC MATERIALS
Cocarbonization of Polyacrylonitrile with Lignin
Yu. N. Sazanov, G. N. Fedorova, E. M. Kulikova, D. M. Kostycheva,
A. V. Novoselova, and A. V. Gribanov
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Received February 8, 2007
Abstract-The boundary and parameters of the thermochemical reaction of lignin and polyacrylonitrile
were determined by dynamic and isothermal thermal analysis. The time, temperature, and concentration
effects of formation of composites, allowing preparation of new carbonizates with enhanced heat resistance
and noticeably higher carbon residue, were studied.
In our previous papers concerned with the possi-
bility of preparing new composite materials (CMs)
based on polyacrylonitrile (PAN) and other synthetic
polymers we noted the positive influence of PAN on
the characteristics of the resulting CMs. However, we
encountered in this line of investigation some tech-
nological and economical problems . To avoid
these difficulties, we made an attempt to prepare CMs
with PAN on the basis of natural macromolecular
compounds [43 6]. The possibility of preparing CMs
based on binary mixtures of PAN with cellulose
ethers, chitin, and chitosan with high heat resistance,
mechanical strength, and ability to carbonization, has
been shown. The results obtained allowed formulation
of basic principles for preparation of carbon composites
by thermochemical cocarbonization of polymers .
In this study, we used lignin (LG) as a component
in combination with PAN. It is well known that LG
is a component of wood (25330 wt %) and is a com-
plex aromatic substance with uncertain chemical struc-
ture  and molecular weight of (23 6) 0 10
This structure is based on various phenol derivatives
randomly bound by oxymethylene bonds. As regards
the reactivity, LG reacts with many organic sub-
stances along the pathways of electrophilic and nu-
cleophilic substitution . As regards polymers, there
are some publications on modification of a series of
thermosetting polymers, such as phenol3formaldehyde,
melamine, urea, and epoxy resins and also rubbers.
These data are concentrated in special literature (pat-
ents, technical reports, processing regulations) and
mainly refer to description of the blending procedure
and characteristics of the resulting CMs .
However, these data are insufficient for making cer-
tain conclusions on features of polymer-analogous
transformations involving LG. Since there are no data
on the reaction of PAN with LG, we studied thermo-
chemical reactions of PAN with LG under the condi-
tions of dynamic and isothermal heating of a blend of
these polymers in order to elucidate the possibility of
preparing CMs based on these substances with account
of principles of cocarbonization of polymers .
As the initial compounds we used PAN synthesized
by the radical polymerization mechanism  and
LG powder recovered using acid hydrolysis .
Dynamic thermal analysis was performed on an MOM
derivatograph (model C, Hungary) at a heating rate
of 10 deg min
in air; weighed portions 503100 mg,
ceramic crucibles. Dynamic and isothermal analyses
of PAN, LG, and their mechanical mixtures in the
form of powders at a PAN : LG ratio equal to 25 : 75,
50 : 50, and 75 : 25 were performed on an installation
for thermovolumetric analysis (TVA)  in a nitro-
gen medium and in a vacuum.
The first stage of studying thermochemical reac-
tions of LG, PAN, and their mixture was identifica-
tion of the main thermal parameters characterizing
the behavior of the samples during their heating from
room temperature to the temperature of complete de-
composition and evaporation of thermal degradation
products or to a certain temperature limit. The TG cur-
ves of the integral weight loss in heating of the sam-
ples at a constant rate to 1000oC are shown in Fig. 1a.