The Using of Graphene Nano‐Platelets for a Better through‐Plane Thermal Conductivity for Polypropylene

Abstract

In‐plane alignment of graphene nanoplatelets (GNPs) in thin thermal interface material layers suppresses the through‐plane heat transport, which limits the performance of materials. In order to suppress the in‐plane alignment of the GNP filler within polypropylene (PP) and increase the through‐plane component, modification of GNP (MG) was performed in this study. For this aim, GNP was treated with diallyldimethylammonium chloride solution and filled with PP at different weight fractions by using a laboratory type high‐speed thermo‐kinetic mixer. The effect of MG loading into PP on thermal conductivity and surface resistivity of PP was measured. With using MG as a conductive filler for PP, instead of GNP, through‐plane conductivity increased by 11%, however in‐plane conductivity decreased by 33%. Modified GNP‐filled PP showed better through‐plane conductivity and surface resistivity than those of unmodified GNP‐filled PP. Tensile and three point bending tests were performed to determine tensile and flexural properties of composites. Dynamic mechanical analysis was carried out to evaluate viscoelastic properties, such as storage modulus and loss modulus of composites. The thermal properties of samples were measured by using a differential scanning calorimetry, thermogravimetric analysis, and thermo‐mechanical analysis. Scanning electron microscopy was utilized to observe the fracture surfaces of the composites after tensile tests. POLYM. COMPOS., 40:E1320–E1328, 2019. © 2018 Society of Plastics Engineers