A combination of graphene and graphene nanoplatelets: An effective way to improve thermal conductivity for polymers

Graphene has emerged as an efficient filler in polymer matrices due to its unique properties. What is not entirely clear, however, is how to transfer the unique attributes exhibited at the nanoscale to the macroscale. The primary focus of this study was on understanding the main causes that lead to the improvement of thermal conductivity for polymers with a hybrid reinforcement material consisting of graphene and graphene nanoplatelets. The thermal properties of epoxy matrix composites filled with the hybrid reinforcement material were studied experimentally in order to provide an effective way to improve thermal conductivity for polymers. Comparisons with other existing reinforcement materials were made in terms of thermal properties. A mathematical model was developed to evaluate the effectiveness of the hybrid reinforcement material in improving thermal conductivity. The results indicated that a twenty-fold increase in thermal conductivity can be achieved for epoxy resins when the content of the hybrid reinforcement material is 8% by weight. The main cause is that the hybrid reinforcement material can significantly reduce interfacial thermal resistance. The hybrid reinforcement material is quite effective compared to other existing reinforcement materials. The thermal performance of the resultant composite materials has no significant degradation at high temperatures.