Conductive polymer composites with double percolated architecture of carbon nanoparticles and ceramic microparticles for high heat dissipation and sharp PTC switching

In classical self-limiting heating devices where conductive polymer composites (CPC) are used, one of the main problems to solve is the stability of properties with time. Different strategies are proposed to stabilize the morphologies during the structuring of these heterogeneous materials. Some of them are well known in the use of co-continuous polymer blends or confinement but the interest of this work is to combine different structuring methods such as volume exclusion, adsorption and multiple percolations to achieve original properties. In fact the CPC developed exhibit enhanced heat dissipation and thermal stability (up to 180 degrees C), independent adjustability of electrical and thermal conductivity, and a sharp and large amplitude PTC effect. These original results were obtained with a co-continuous structure associating a thermally conductive polymer phase (syndiotactic poly(styrene) (sPS) filled with aluminum oxide (Al2O3) or boron nitride (BN)) with an electrically conductive polymer phase (high-density poly(ethylene)) (hdPE) filled with carbon nanoparticles (CNP) in appropriate proportions.