69
Mater. Res. Soc. Symp. Proc. Vol. 1371 © 2012 Materials Research Society
DOI: 10.1557/opl.2012.
Polymer Nanohybrids With High Electrical Conductivities
R. Yañez-Macías
1
, P. González-Morones
1
, C. Ávila-Orta
1
, S. Torres-Rincón
1
, J. Valdéz-Garza
1
,
A. Rosales-Jasso
1
, J.G. Telles-Padilla
1
, A. Saénz-Galindo
2
1
Research Center for Applied Chemistry (CIQA), Blvd. Enrique Reyna No 140, C. P. 25253,
Saltillo, Coah.
2
Faculty of Chemical Sciences, Autonomous University of Coahuila (UAC), Blvd V. Carranza
s/n, Col. República Oriente, Saltillo, Coah.
.
ABSTRACT
Multiwalled carbon nanotube (MWCNT)/Nylon-6 nanohybrids were prepared by in situ
polymerization under microwave irradiation. The effect of time and power of irradiation on the
surface conductivity of the nanohybrid was studied. It was observed that the resistivity increases
with irradiation time at low microwave power (200W). On the other hand, at high power (600W)
an opposite behavior was observed. And at intermediate power (400W) the resistivity was
independent of the irradiation time. Resistivity values range from 10
2
to 10
1
Ω/sq. This behavior
was associated with the polymer nanocoating covering the surface of the carbon nanotubes.
INTRODUCTION
The use of microwave energy is an alternative method to carry out polymerization
reactions due to its selective and effective heating. [1] Because of the structure, carbon nanotubes
(CNT) and ε-caprolactam can absorb this type of energy [2] making it possible to heat and reach
the necessary reaction temperature.
The term nanohybrid involves covalently linking a functional group directly to the
surface of a nanoparticle. The defect sites on the CNTs surface allow attachment of functional
groups or polymer moieties
3
. The functionalization of CNTs with polymers might represent
some advantages to ensure the compatibility of the nanoparticle with the polymer matrix or to
fabricate conductive materials such as nanotubes but with polymer properties.
EXPERIMENTAL DETAILS
Reactive grade ε-caprolactam (monomer) and aminocaproic acid (initiator) were obtained
from Sigma Aldrich, MWCNT were purchased from Nanoamor Inc. USA (purity 95%, average
external diameter 30-50 nm, length 10-20 μm). The microwave polymerizations were conducted
in a MARS X microwave oven with an operating power of 200, 400, 600 W and frequency of
2.45 GHz.
To synthesize Nylon-6/MWCNT nanocomposites, amounts of 26.1 g of ε-caprolactam,
3.9 g of aminocaproic acid and 0.6 g of MWCNT were ground and mixed together and placed
into a quartz vessel. The reaction temperature was 230°C. The products were first dissolved in
formic acid, and subsequently washed with methanol to remove residual monomer, this
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