Abstract:
Polyamide and its nanocomposites have shown remarkable properties to be used for
electrical applications, especially in high voltage cables or motor insulation applications.
However, in these environments the insulation materials are exposed to humid and high
temperature conditions which deteriorates the structure of polyamide-based insulators
hence degrades its electrical properties. To analyze the effect of temperature and humidity
on dielectric properties, neat polyamide (nPA/PA-0), 1wt.% polyamide ZnO
nanocomposite (PA-1), 3wt.% polyamide ZnO nanocomposite (PA-3), 5wt.% polyamide
ZnO nanocomposite (PA-5) and 7wt.% polyamide ZnO nanocomposite (PA-7) were
prepared. These composites were then subjected to accelerated conditions of humidity and
temperature (85°C & 85% RH) in a hydrothermal aging chamber for 300 hours. The
relative permittivity and tan δ depending on temperature and frequency of each sample
were analyzed after every 100 hours. The analyses showed that increase in temperature
results in high relative permittivity and loss factor and among all the nanocomposites PA3
performed
better.
The
investigation
for
frequency
dependency
of
dielectric
properties
showed
that relative permittivity and dissipation factor decrease with increase in
frequency for which PA-1 performed better. The effect of elevated temperature conditions
was significant as the aged composites showed an increase in the values compared to
unaged composites but they were in acceptable limit required for a good insulating
material. The effect of addition of ZnO was also observed as nanocomposites performed
better than the neat polyamide and nano filler performed even better due to intactness of
composite structure or greater surface area and surface energy.
