ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 1, pp. 165−172. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © S.N. Malakhov, A.V. Bakirov, P.V. Dmitryakov, S.N. Chvalun, 2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89, No. 1, pp. 140−148.
AND POLYMERIC MATERIALS
Nanocomposite Nonwoven Materials Based on Polyamide-6
and Montmorillonite, Prepared
by Electrospinning of the Polymer Melt
S. N. Malakhov
, A. V. Bakirov
, P. V. Dmitryakov
, and S. N. Chvalun
National Research Center “Kurchatov Institute,” pl. Akademika Kurchatova 1, Moscow, 123182 Russia
Karpov Institute of Physical Chemistry, Vorontsovo Pole 10, Moscow, 105064 Russia
Received January 11, 2016
Abstract—The effect of montmorillonite on the structure and properties of nonwoven microﬁ brous materials
based on polyamide-6 and prepared by electrospinning of the polymer melt was studied. Addition of 3% mont-
morillonite into the melt increases its viscosity and electrical conductivity, with the mean diameter of the formed
ﬁ bers increasing from 8 to 12 μm. As shown by X-ray diffraction, IR spectroscopy, and differential scanning
calorimetry, pellets of the pristine polyamide are characterized by prevalence of crystals of the stable α-form,
whereas in the composites and nonwoven materials the metastable γ-form prevails. Addition of montmorillonite
only slightly inﬂ uences the contact angles, and the resulting materials exhibit nearly superhydrophobic properties.
Polymer composites containing nanoparticles attract
today much attention of researchers and engineers.
Addition of a small amount of a nanosized ﬁ ller into
a polymer matrix allows signiﬁ cantly improve the
polymer characteristics (mechanical, electrophysical,
thermal, barrier) or imparting to it new properties, e.g.,
antibacterial or wound-healing.
Polyamide-6 (PA) exhibits superb physicochemical
characteristics (good mechanical properties, heat re-
sistance, resistance to a wide range of chemicals) and
has therefore found wide use in production of various
(in particular, ﬁ brous) materials. Nanoclays, primar-
ily montmorillonite (MMT), are widely used as ﬁ ll-
ers for polyamide-6. MMT is used both for preparing
nanocomposites by the melt procedure [1–6] (including
the procedure that involves the subsequent ﬁ ber forma-
tion by melt extrusion ) and for preparing nonwoven
nanocomposite materials by electrospinning of the poly-
mer solution [8–14].
For example, a series of nonwoven materials with
the mean ﬁ ber diameter of 100–600 nm, containing
1–10 wt % MMT, were prepared by electrospinning
from solutions of polyamide in hexaﬂ uoroisopropanol
 and formic acid [9–14]; the crystal structure, heat
resistance, and mechanical properties of these materials
were studied. Li et al.  showed that addition of 5%
ММТ led to an increase in the Young’s modulus of a
single ﬁ ber by a factor of 2 relative to the ﬁ bers of the
same diameter prepared from pure polyamide. A decrease
in the mean ﬁ ber diameter led to an increase in the
Young’s modulus and to enhancement of the mechanical
properties of the ﬁ brous materials. As shown by Li et al.
, in nonwoven materials containing ММТ the ﬁ ber
surface is considerably rougher, and, correspondingly,
the contact surface area between water molecules and
nanoﬁ bers is larger than that in the materials made
of pure polyamide. As a result, the water absorption
increased from 7.4% for pure PA to 13.6 and 25.5% for
the material containing 1 and 2% ММТ, respectively.
Agarwal et al.  suggested using a nanoﬁ brous
membrane based on polyamide with the addition of
5% nanoclay as one of layers for packaging foodstuffs.