Electrophysical properties of woven polymer mesh fabrics
Dragana D. Cerovic ,
1,2
Koviljka A. Asanovic ,
3
Slavica B. Maletic ,
1
Filip S. Marinkovic,
1
Ivan M. Petronijevic,
1
Jablan R. Dojcilovic
1
1
Faculty of Physics, University of Belgrade, Studentski trg 12, 11000, Belgrade Serbia
2
The College of Textile Design, Technology and Management, Starine Novaka 24, 11000 Belgrade, Serbia
3
Department of Textile Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000
Belgrade, Serbia
Correspondence to: D. D. Cerovic (E-mail: cecadragana@ff.bg.ac.rs)
ABSTRACT: The investigation was performed on three woven mesh fabrics made of polyethylene terephthalate (PET), polyamide
(PA) 6.6 monofilaments, and PA 6.6 with carbon filament (CF). The dielectric properties were examined as functions of frequency at
room conditions and as functions of frequency and temperature under the vacuum. It was observed at lower frequency higher changes
of dielectric permittivity for the sample with CFs at room conditions. For PET and PA 6.6, dielectric permittivity in the vacuum was
steady and little lower; furthermore, dielectric spectra showed the existence of γ-, β-, and α-relaxations. The dc volume electrical resistiv-
ity was investigated in the function of relative humidity at room temperature for PA 6.6 and PA 6.6 with CF. For the sample with the
CF, a decrease in the dc electrical resistivity of nine orders of magnitude in the direction with CF was registered as compared to the
direction without a conductive filament. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48456.
KEYWORDS: dc electrical resistivity; dielectric properties; polymer mesh
Received 5 April 2019; accepted 11 August 2019
DOI: 10.1002/app.48456
INTRODUCTION
Fibrous polymeric materials in form of woven fabrics are pre-
ferred to other types of material when the end product needs to
be flexible, thin, lightweight, and mechanically resistant, which is
especially achieved in cases where woven fabrics are made from
monofilaments. The widespread use of woven fabrics for the
application as the substrates in electronics implicates the need to
investigate their electrophysical properties (dielectric properties
and dc volume electrical resistivity). The relative dielectric per-
mittivity describes the ability to polarize a material subjected to
an electrical field until the dielectric tangent of losses corresponds
with energy losses in materials. Measuring these parameters, it is
possible to monitor the dynamics of the band and different
molecular groups under the influence of an electric periodic field
in a wide temperature and frequency range. Also, measuring the
dc electrical resistivity, it is possible to monitor how strongly that
fabric opposes the flow of the electric current in a different air
humidity conditions. Woven fabrics are composites of fibers, air,
and moisture, whose electrophysical properties under the given
conditions depend on the basic polymeric substance, the manner
in which materials are formed, as well as the type of
arrangement.
1–3
Furthermore, the relative humidity of the envi-
ronment significantly influences the values of electrophysical
properties of porous structures like woven materials.
4,5
For real
applications, it is important to know how internal (properties of
the material) and external (humidity, temperature, and fre-
quency) factors influence electrophysical properties, that is, the
behavior of woven fabrics as the substrates in order to minimize
any unwanted effects.
Polyamide (PA) and polyethylene terephthalate (PET) are complex
engineering semi-crystalline polymers used for a wide range of
applications in different forms, among others, as substrates in
electronics.
6–8
PA 6.6, also called nylon 6.6, is represented by the
repeating unit CONH(CH
2
)
6
NHCO(CH
2
)
4
. PET has an ali-
phatic sequence COOCH
2
CH
2
OCO , which, with its six main
chain bonds matches the CH
2
sequences in aliphatic PA 6.6,
alternating with benzene rings.
1
The basic difference between these
two linear polymers is that the PA 6.6 fibers are made up of linear
macromolecules, whose structural units are linked by the
NH CO group, which can form hydrogen bonds, whereas PET
fibers are composed of benzene rings, CH
2
and COO
groups, none of which attracts water strongly.
1
The condensation
polymers, PET and PA 6.6, can have only one possible configuration
but can take up many different conformations.
9
The value of the
glass-transition temperature (T
g
) is lower for PA 6.6 (50
C,
10
) than
that for PET (67
C,
10
), because PET contains a large fraction of
© 2019 Wiley Periodicals, Inc.
48456 (1 of 7) J. APPL. POLYM. SCI. 2019, DOI: 10.1002/APP.48456