Abstract:
Dielectric polymers have drawn great interest due to their applications in energy harvesting/storage devices, sensors and actuators owing to the merits of high breakdown strength, good flexibility, easy processing and low cost. However, how to achieve the combination of high dielectric constant and low dielectric loss is still an important scientific problem to be solved in this field. Therefore, based on a strategy of "bridges" effect between filler and matrix, this work prepared the epoxidized natural rubber (ENR) based dielectric composites (P-rGO/ENR) with segregated structure through latex blending and in-situ hot pressing reduction, using graphene oxide (GO) as filler, ENR latex as the matrix, and phytic acid (PA) as a modifying agent. The results show that PA can “bridge” GO and ENR by ring-opening reactions, respectively. As a result, the interfacial interaction between GO and ENR can be greatly enhanced. At the same time, the ENR latex particles force the GO nanosheets into the interstitial space between them because the ENR latex particles act as an excluded volume. As a result, GO nanosheets are self-assembled and coated on the surface of ENR latex microspheres. Finally, during the drying or co-coagulation procedure, these GO-coated ENR latex microspheres connect with each other to form a continuous three-dimensional segregated structure. The dielectric constant of the P-rGO/ENR composite (2wt%GO), is as high as 569903 and the conductivity is 10
−4 S/cm as well as maintains a low dielectric loss (<5) at 100 Hz.