Synthesis and characterization of polyimide/liquid acrylonitrile-butadiene rubber composite films

High energy storage composite films were synthesized by solution blending polyimide (PI) and liquid acrylonitrile-butadiene rubber (LNBR). Experimental results showed that the composite films exhibited outstanding mechanical, thermal, and dielectric properties. When the content of LNBR was 5 wt%, the composite films showed remarkable thermal properties, superior tensile strength (106.02 MPa) and tensile modulus (2.57 GPa), high dielectric constant (4.79, 1 kHz), and low dielectric loss (0.0075, 1 kHz). Noticeably, the breakdown strength still remains at a high level (303.59 kV mm⁻¹). In addition, the dielectric constant of the composite films decreased slightly with the increasing frequency. The dielectric loss were less than 0.025 within the testing frequency range. In particular, the composite films exhibited high energy storage density (up to 1.95 J cm⁻³). This study indicated that the PI/LNBR composite films will be a promising candidate for high energy storage materials.