Fabrication of functionalized graphene filled carboxylated nitrile rubber nanocomposites as flexible dielectric materials
Hexadecylamine (HDA) was used to covalently functionalize graphite oxide followed by its reduction to form functionalized graphene nanosheets (GNS–HDA). Subsequently, GNS–HDA has been used as filler in fabricating carboxylated nitrile rubber (XNBR) nanocomposites via solution mixing. Mechanical measurements of XNBR/GNS–HDA-2 nanocomposites compared to neat XNBR exhibited 60% improvement in tensile strength (TS), 62% improvement in elongation at break (EB) and 13% reduction in Young's modulus (YM). Thermogravimetric studies demonstrate that incorporation of GNS–HDA into a XNBR polymer matrix increases the thermal stability of composites with GNS–HDA loading. Further investigations show significant enhancement in the dielectric constant of XNBR/GNS–HDA-2 (127.6) compared to neat XNBR (8.9) at 100 Hz. The corresponding value of the dielectric loss of the composite was enhanced only ∼2 times. Such enhanced TS, EB, reduced YM and dielectric constants while retaining low dielectric loss enables the possible application of XNBR/GNS–HDA as flexible dielectric materials in electronic devices.