ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 6, pp. 818−823. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © O.V. Popova, M.Yu. Serbinovskii, 2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87, No. 6, pp. 808−813.
AND POLYMERIC MATERIALS
Graphite from Hydrolysis Lignin
: Preparation Procedure,
Structure, Properties, and Application
O. V. Popova and M. Yu. Serbinovskii
Academy of Engineering and Technology, Southern Federal University, Taganrog, Rostov oblast, Russia
Received May 19, 2014
Abstract—The possibility of preparing graphite from hydrolysis lignin using pyrolysis and graphitization processes
was considered. The inﬂ uence of lignin milling on the granulometric composition of the graphite obtained was
studied. The structure of graphite prepared from lignin was conﬁ rmed by X-ray diffraction analysis. Prospects
for using graphite materials prepared from lignin in electrochemical and other technologies are demonstrated.
Finely dispersed graphites are highly demanded
today by electrochemistry and other branches of
engineering. However, preparation of ﬁ nely dispersed
fractions from natural graphites involves problems
related to the structure and antifriction properties of
graphite. Therefore, it is interesting to examine the
possibility of preparing graphitized materials whose
dispersion is ensured in the step preceding the raw
material graphitization and in the course of modiﬁ cation
of the already prepared artiﬁ cial graphite. Preparation of
such materials from wastes from processing renewable
raw materials is particularly topical.
It is known that hydrolysis lignin (HL) is a natural
polymer, a large-tonnage waste from industrial hydrolysis
of vegetable raw materials. From the viewpoint of
chemical structure, it is a macromolecule largely
consisting of fused benzene rings and thus is a condensed
aromatic system . The HL structure is formed in the
course of percolation hydrolysis, which is performed
at elevated pressures (0.6–0.9 MPa) and temperatures
of up to 200° . The process involves substantial
modiﬁ cation of the lignin macromolecule: condensation,
oxidation, demethylation, etc. . As a result, in
contrast to the structure of natural lignin, the structure
of HL is characterized by considerably higher content of
condensed aromatic system.
It is also known that the pyrolysis of organic macromo-
lecular compounds and organic polymers is accompanied
by isomerization, polymerization, and condensation .
This fact accounts for formation of condensed aromatic
structures at increased temperatures of HL heat treatment
without air access. Indeed, as shown in [5–7], when lignin
pyrolysis is performed without oxygen access or at its
deﬁ ciency, degradation processes in lignin macromol-
ecules mainly consist in elimination of active groups and
only weakly involve the aromatic system. Presumably,
the heat treatment of HL without oxygen access or at
its deﬁ ciency at high temperatures, in particular, above
1000°, should involve elimination of all the active
groups and hydrogen and should not lead to destruction
of the polymeric carbon structure. That is, theoretically
the carbon material obtained from lignin should be suit-
able for further ordering of carbon atoms and formation
of the graphite crystallographic structure. It should be
noted that not all the carbon raw materials prepared from
various raw materials by various procedures can undergo
graphitization ; therefore, the possibility of preparing
graphite from lignin required proving.
We have found that the carbon material obtained by
HL thermolysis can undergo graphitization. Thus, the
assumption has been experimentally conﬁ rmed, and
artiﬁ cial graphite has been prepared from HL.