Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 2, pp. 303−308.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © A.V. Blokhin, M.V. Shishonok, O.V. Voitkevich, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 2, pp. 316−322.
AND POLYMERIC MATERIALS
Thermodynamic Properties of Cellulose of Various Structures
in the Temperature
A. V. Blokhin, M. V. Shishonok, and O. V. Voitkevich
Belarussian State University, Minsk, Belarus
Received July 19, 2010
Abstract—The energies of combustion of cellulose samples with different supramolecular structures were
determined, and the enthalpies of formation of these substances were calculated. Reliable values of the heat
capacity were obtained.
Exhaustion of fossil fuel resources and deterioration
of the environment by gas emissions cause growing inter-
est in renewable power sources. Available resources for
fuel production from renewable raw materials are wood,
straw of cereals and oil-bearing (rape) crops, and starch-
containing agricultural products (potatoes, beetroots).
Power engineering based on plant biomass becomes
self-supporting and competitive with the power
engineering based of fossil fuels. To substantiate
technologies for reprocessing plant biomass into fuel, it
is necessary to have reliable values of the thermodynamic
characteristics of the components. The main component
of plant ﬁ bers is cellulose. At the same time, the
available data, published as early as the 1970s, include
only a few graphic dependences of the heat capacity of
cotton cellulose on temperature and on the processing
conditions [1, 2]. Furthermore, published data on low-
temperature heat capacity of cellulose are restricted
to temperatures exceeding 80 K. The modern level of
engineering allows the measurements to be performed
starting from 5 K. Properties of polymers directly depend
on their supramolecular organization. Thus, it is topical
to study thermodynamic properties of cellulose samples
of different origins and supramolecular structures in
a relatively wide temperature interval.
Experiments were performed with cellulose samples
of various origins and structures: cotton microcrystalline
cellulose of Ankir grade (1); wood sulﬁ te cellulose
produced by Kotlas Pulp-and-Paper Combine,
Public Joint-Stock Company [quality certiﬁ cate, TU
(Technical Speciﬁ cation) 5411-027-05711131–95] (2);
straw cellulose produced by nitric acid cooking of rape
straw pedicels [3–5] (3); and wood amorphous cellulose
produced by regeneration of wood ﬁ bers from a solution
in a nitrogen(IV) oxide–ethyl acetate mixture, following
a specially developed procedure  (4). Prior to tests,
all the samples were dried at 130°C to constant weight,
with the subsequent keeping in a desiccator over P
for no less than 72 h.
X-ray phase analysis of cellulose was performed
with an HZG-4A diffractometer (Carl Zeiss, Jena)
using Ni-monochromated CuK
radiation. The patterns
were recorded in the step-by-step mode. Samples were
pressed in monolithic round pellets of the same shape.
The degree of crystallinity k of cellulose (Table 1) was
calculated from the diffraction patterns recorded under
identical conditions, following Segal’s procedure .
The low-temperature heat capacities C
5–370 K for samples 1 and 2, 80–370 K for samples 3
and 4) were measured using a TAU-10 automatic vacuum
adiabatic calorimeter (Thermis, Moscow) (Table 2). The
temperature step of measuring the heat capacity did not
exceed 2.5 K. The device and procedure for measuring
the heat capacity are described elsewhere . The
accuracy of measuring the heat capacity in the adiabatic