Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 12, pp. 2065−2070.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © I.M. Lipatova, E.A. Mezina, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 12, pp. 1981−1986.
PROCESSES AND EQUIPMENT
OF CHEMICAL INDUSTRY
Effect of the Composition and Mechanical Activation
of Aerosil Suspensions in Chitosan Solutions on Properties
of Films Formed from These Suspensions
I. M. Lipatova and E. A. Mezina
Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russia
Received April 8, 2011
Abstract—Rheological properties of aerosil suspensions in chitosan solutions and the effect of the ﬁ ller content
of these suspensions and mechanical activation on the strength and sorption capacity of aerosil-chitosan ﬁ lms
produced from these suspensions were studied.
The interest in chitosan-based composite materials
has particularly quickened in the last decades.
Promising materials are organic-inorganic composites
in which aerosil and other silicon-dioxide-containing
materials ﬁ nely dispersed in chitosan are used as ﬁ llers.
Composites of this kind may be of interest for use as
sorbents , wound dressings providing prolonged
release of medicinal preparations , hybrid membranes
, and complex catalytic systems . Properties of
these materials are determined by the supramolecular
organization of the polymeric matrix, as well as by the
dispersity and surface state of ﬁ ller particles.
A ﬁ ller can play an accessory role as an agent
controlling the sorption properties of chitosan, but may
also serve as the target sorbing component, with the
biopolymer as a binder. An important factor in the latter
case is the accessibility of the surface of ﬁ ller particles
to the sorbate, determined by the structure of boundary
polymeric layers. Because the melting point of chitosan
exceeds its decomposition points, the only way to obtain
ﬁ lled articles based on this polysaccharide is to disperse
the ﬁ ller in aqueous weakly acid chitosan solutions,
with the subsequent removal of the solvent. In this case,
the properties of the resulting composite materials are
predetermined already in the stage in which the molding
suspensions are prepared.
It has been shown previously that characteristics of
ﬁ lled polymeric materials can be purposefully varied
by mechanical activation of the starting suspensions by
hydroacoustic treatment in rotary-pulsatory apparatus
The goal of our study was to examine the effect of the
composition and mechanical activation of suspensions
in chitosan solutions on physicomechanical and sorption
properties of ﬁ lms produced from these suspensions.
As objects of study served commercial chitosan with
a molecular mass of 120 000 and degree of deacetylation
of 0.78 (Bioprogress Private company, Shchelkovo).
The suspensions were prepared by introduction of
weighed portions of aerosil into 2% chitosan solutions
in 2% acetic acid.
The chitosan solutions and chitosan-based
suspensions were mechanically treated in a laboratory
rotary-pulsatory apparatus (RPA) in the recycle mode.
The thermostated working chamber of the apparatus
is formed by the rotor and stator, whose cylindrical
rings have rectangular channels. The average spacing
between the rotating and immobile members of the
working chamber is 0.3 mm. The rotor rotation speed is
5000 rpm, to which corresponds the shear rate gradient
of 17.4 104 s
. The treatment duration was 10 s.