The effect of temperature on the dielectric properties of the newly blended rubber
material Natural Rubber (NR) with Nitrile Butadiene Rubber (NBR) at 80:20 concentrations
was investigated. The dielectric constant and dielectric loss were carried out into two ways, i.e.,
the temperature dependences and frequency dependences. Low frequency range
measurements were conducted with the impedance spectrometer and high frequencies used
microwave bench system X and K band. The temperature dependence of dielectric behavior is
constancy between the frequency ranges 1584.9 HZ and 5.01E6 Hz but the dielectric constant
decreases as frequency increases from 1 HZ to 1E7 HZ and 9 GHZ to 26 GHZ at room temperature. It
was concluded that mechanical blending of the two rubber materials is the simplest mean
to obtain a variety of physical properties from the constituent rubber materials NR and NBR.
Rubber is one of the most important polymers. It
is extensively used in many applications because of its unique performance and number of specific properties like energy
absorption, damping characteristics, long service life at ambient
temperature, with low cost and high performance. In an attempt to get further applications instead of making a new
elastomer, the blend can be made between any two already available rubber materials. Physical
mixing of two or more different elastomers is known as blending. In a rubber blend, the
constituent rubber materials are usually present in significant proportions
of weight or volume with respect to each other, but seldom all in equal proportions. There is no doubt that the
main reason for blending is economy (Haji Sidek et al., 2001a). The blending of different
rubber materials is the most promising and feasible approach (Haji Sidek et al., 2001b) and has become technically
important. Although a large number of combinations of rubbers
can be blended, there are a few that lead to totally miscible systems (Kyung-Sub Lee et al., 2005). They found that the adhesions between uncross linked layers of isoprene rubber and
Nitrile Butadiene Rubber (NBR) is dependent on
rate and temperature .
Since these blends find wide applications as insulating materials in electrical appliances due
to their low dielectric loss, the dielectric analysis of rubber materials and their blends might
provide even more useful information. The thermal stability as well as the thermal and electrical properties
of rubber materials which are affected by temperature changes play an important role in
many industrial applications such as wire and cable insulation, heat shrinkable materials, rubber
tyres, and electronic packaging (Badway, 1996). The mechanical blending of two rubber materials is
the simplest means to obtain a variety of physical properties from the constituent rubber
materials like Natural Rubber (NR), NBR and NR blended with NBR to enhance the oil resistance of NR
and thermal resistance properties of NBR. Chuah et al. (1995) carried out experiments to test
the hypothesis using carbon black as the filler in blends of NR and NBR with an acrylonitrile content
of 45%. The present study is focused on the behavior of NR/NBR, which are blended in the
ratio of 80:20. The objective of this study is to investigate temperature dependence of dielectric
properties in gum and reinforced states.
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