ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 6, pp. 1057−1061. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © A.V. Dedov, E.A. Vlasenko, 2015, published in Zhurnal Prikladnoi Khimii, 2015, Vol. 88, No. 6, pp. 963−967.
Mechanism of Plasticizer Evaporation from Polyvinyl Chloride
Filled with Dispersed Carbon Fiber
A. V. Dedov and E. A. Vlasenko
Ivan Fedorov State University of Printing Arts, ul. Pryanishnikova 2A, Moscow, 127550 Russia
Received June 9, 2015
Abstract—The mechanism of dioctyl phthalate evaporation from polyvinyl chloride ﬁ lms ﬁ lled with dispersed
carbon ﬁ ber was studied by thermal gravimetric analysis. At a low degree of ﬁ lling, the evaporation is controlled
by the diffusion of the plasticizer in the polymer. At increased degrees of ﬁ lling, evaporation of the plasticizer from
the ﬁ lm surface becomes the limiting step. The change in the plasticizer evaporation mechanism is associated with
the effect of the carbon ﬁ ber on the formation of the polymer matrix structure and on the plasticizer distribution.
One of the ways of modiﬁ cation of the physicom-
echanical properties of materials based on plasticized
polyvinyl chloride (PVC) is introduction of dispersed
carbon ﬁ ber . In particular, introduction of carbon
ﬁ ber into PVC imparts electrical conductivity to the
material and eliminates the problem of the generation of
static electricity . In operation of PVC-based materi-
als, changes in their properties are mainly determined by
the plasticizer desorption. A decrease in the plasticizer
content leads to an increase in the glass transition point
of PVC. Reliable determination of the mechanism of the
plasticizer desorption from PVC with different degrees
of ﬁ lling with carbon ﬁ ber is of practical signiﬁ cance.
The desorption of plasticizers from PVC is determined
by their transfer from the bulk of the material to its
surface and by the removal from the surface via different
pathways depending on the phase state of the surrounding
medium. The relay mechanism of desorption determines
the dependence of the process kinetics either on the rate
of the plasticizer transfer from the bulk of PVC to the
surface or on the rate of its transfer from the surface to
the surrounding medium . The step with the lowest
rate of the plasticizer transfer is the limiting step of the
desorption process. Therefore, along with the problem
of modeling the desorption kinetics, the problem of
determining the limiting step of the process and its
dependence on the structure of ﬁ lled PVC is topical.
Determination of the limiting step is of practical
importance when studying the evaporation of plasticizers
under the conditions when the transfer ﬂ uxes from the
bulk to the surface and from the surface are close [4–6].
In extraction and migration (contact of PVC with a solid
capable to take up the released plasticizer), the rate of the
plasticizer transfer from the surface to the surrounding
medium is, as a rule, considerably higher than the rate of
its transfer from the bulk to the PVC surface.
When the limiting step of the evaporation is the
plasticizer transfer from the bulk to the surface, the
diffusion coefﬁ cient of the plasticizer in PVC is used as
a kinetic parameter reﬂ ecting the process rate. In the case
when the transfer from the surface is the limiting step
of the desorption, the plasticizer volatility is used as the
kinetic parameter . Determination of the limiting step
of the evaporation process ensures the adequate choice
of methods for reducing the process rate. Apparently,
methods for reducing the plasticizer volatility differ from
methods for reducing the rate of its diffusion in PVC.
In this study, the mechanism of the plasticizer
evaporation from ﬁ lled PVC was studied using thermal
gravimetric analysis (TGA) [7, 8]. The model for
predicting the kinetics of one-step weight loss processes