Relationship between the Relative Dielectric Constant and the Monomer Sequence of Acrylonitrile in Rubber

Abstract

Acrylonitrile-butadiene rubbers (NBRs) have a lower glass transition temperature (T g) and a higher dielectric constant than other rubbers. To understand how a low T g and a high dielectric constant are compatible, we focused on the acrylonitrile (AN) monomer sequence in rubber and synthesized random and alternating copolymers to evaluate the effect of the sequence. The AN monomer sequence dependence of the relative dielectric constant was investigated by the C–N stretching vibration of the nitrile group through Fourier transform infrared spectroscopy and internal rotation potential energy measurements around the C–C bond within the nitrile group based on dimer model calculations. The alternating copolymers, including NBR, showed a higher dielectric constant than random copolymers. The alternating copolymer shifted from ∼2243 cm–1 for polyAN to ∼2236 cm–1 for NBRs, while the random copolymer only shifted to ∼2239 cm–1. The peak of the C–N stretching vibration was correlated with the AN sequence. The sequence dependence of the shift can be explained by the C–N bond length calculation. The internal rotation potential energy between gauche and trans of the NBR model was the lowest, indicating that the NBR main chain is flexible and that AN in the main chain rotates easily. Therefore, NBR has a high dielectric constant and a low T g because of the presence of an alternating sequence and the flexibility of the NBR main chain.

Capacitive Interdigitated Electrodes Sensor for the Field Device to Measure Moisture Content in the Nitrile Gloves Manufacturing Industry

“…Consistent with our present findings, Wang et al (2017) also reported that materials with high moisture exhibits greater capacitance due to high dielectric constant of water (ε r = 80). NBR at 100Hz have a dielectric constant of 10 or more at room temperature (Matsuno et al, 2021). During drying process, water diffuses and dries off from glove surface, causing drastic drop in gloves dielectric constant.…”

Capacitive Interdigitated Electrodes Sensor for the Field Device to Measure Moisture Content in the Nitrile Gloves Manufacturing Industry

“…Consistent with our present findings, Wang et al (2017) also reported that materials with high moisture exhibits greater capacitance due to high dielectric constant of water (εr = 80). NBR at 100Hz have a dielectric constant of 10 or more at room temperature (Matsuno et al, 2021). During drying process, water diffuses and dries off from glove surface, causing drastic drop in gloves dielectric constant.…”

Actuator Performance of a Hydrogenated Carboxylated Acrylonitrile–Butadiene Rubber/Silica-Coated BaTiO3 Dielectric Elastomer

“…An elastomer having flexibility and a high dielectric constant is needed. In our previous research, we reported that HXNBR exhibited a high dielectric constant (14) and flexibility . Additionally, Poikelispää et al reported the high actuation performance of NBR rubbers .…”

“…In our previous research, we reported that HXNBR exhibited a high dielectric constant (14) and flexibility. 27 Additionally, Poikelispaä̈et al reported the high actuation performance of NBR rubbers. 2 This suggested that a DEA composed of HXNBR (having a high dielectric constant) and silica-coated BaTiO 3 particles can be applied to a high electric field, leading to high generated stress and strain.…”