Green dielectric materials composed of natural graphite minerals and biodegradable polymer

Polymeric nanocomposites are a promising dielectric due to their low cost, easy processability and flexibility but most polymers are difficult to treat and recycle leading to “white pollution”. Here, we report an eco-friendly “green” dielectric material made from natural graphite minerals and biodegradable poly(butylene succinate) synthesized by solution casting and hot pressing. Dielectric constant of resulting composite films agreed quite well with percolation theory and a low percolation threshold fc = 5.98% was obtained due to a high aspect ratio of natural graphite minerals. Composite films possessed a high dielectric constant of 113, around 28 times higher than that of pristine PBS (103) when volume fraction reached 5.5%. Furthermore, dynamic mechanical properties of composite films can be improved at the same time. Dielectric constant of composite films can be greatly improved by incorporating natural graphite minerals while mechanical flexibility can be maintained to be as good as that of pure polymer matrix.