ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 8, pp. 1309−1316. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © I.A. Kazakov, A.N. Krasnovskii,
2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89, No. 8, pp. 1062−1070.
AND POLYMERIC MATERIALS
Effect of Functionalized Multiwalled Carbon
Nanotubes on the Feasibility of Fabrication
of Composite Glass Fiber Reinforced Plastic Rebars
I. A. Kazakov and A. N. Krasnovskii*
STANKIN Moscow State University of Technology, Vadkovskii per. 1, Moscow, 127055 Russia
Received August 2, 2016
Abstract—The effect of COOH-functionalized multiwalled carbon nanotubes on the temperature–velocity condi-
tions of the fabrication of composite glass ﬁ ber reinforced plastic rebars (so-called needletrusion) used in building
was studied. EPIKOTE 862 epoxy oligomer (Bisphenol F diglycidyl ether) in combination with EPICUREW cur-
ing agent (aromatic diamine) in 100 : 26.4 ratio was used as binder. The use of functionalized multiwalled carbon
nanotubes as additives to the unmodiﬁ ed epoxy binder for fabrication of composite materials by needletrusion
allows production of high-quality items with the required characteristics without loss in the production capacity.
It is preferable to introduce nanotubes in an amount of no more than 0.2 wt %.
Carbon nanotubes (CNTs) exhibit unique thermal,
mechanical, and electric properties owing to structural
integrity, high speciﬁ c surface area, high levels of
strength and electrical conductivity, and possibility
of covalent interactions via surface functional groups
[1–5]. High speciﬁ c surface area of CNTs considerably
enhances the capability of the matrix for stress transfer,
which makes composite materials with CNT additions
promising in building industry, in particular, in
production of composite rebars .
Composite rebars are bars of carbon, glass, or basalt
ﬁ bers with a special external layer ensuring adhesion of
the bar to concrete. Epoxy resins are widely used as the
main component of the binder in rebar production owing
to high levels of their mechanical and chemical properties
and to high temperature of thermal deformation.
High level of mechanical and chemical properties
of epoxy polymers is due to curing reactions in which
a low-molecular-mass resin transforms into a polymer
matrix of three-dimensional network structure. Curing
is initiated using a wide range of curing agents such as
aliphatic or aromatic amines, anhydrides, etc.
A study of curing of epoxy composites is important for
the development and calculation of process parameters.
One of the most informative and well-developed
methods for studying the kinetics of chemical reactions
is differential scanning calorimetry (DSC). Numerous
DSC studies have shown that addition of CNTs to the
resin can inﬂ uence the curing kinetics.
Owing to high speciﬁ c surface area and presence of
various surface functional groups, CNTs, when added
to epoxy resin, not only improve the heat resistance,
strength, modulus characteristics, and bearing capacity,
but also inﬂ uence the curing process, altering the ﬁ nal
properties of the produced items [7–13].
As noted by Qiu et al. , CNTs in a resin can act
as a catalyst, whereas other studies show that CNTs
decelerate the curing [15–17]. Tao et al.  found that
addition of CNTs decreased the total heat of the reaction
and the ﬁ nal degree of curing. Yang et al.  found
that amino groups on the surface of multilayered CNTs
added in a small amount decelerated the curing relative
to the initial epoxy resin, but at higher concentrations
they appreciably decreased the activation energy of