Graphite films/carbon fiber fabric/ polyurethane composites with ultrahigh in-plane thermal conductivity and enhanced mechanical properties

Thermally conductive composites have attracted great attention in virtue of their crucial role in thermal management. In this work, laminated composites were prepared by laying graphite films (GF) and carbon fiber fabrics (CF) in a certain order, then penetrating thermoplastic polyurethane (TPU), finally hot-pressing. In order to enhance the inter-layer strength, the graphite films were perforated with arrays of 1 mm holes in diameter which have intervals of 4 mm and permit the seeping of liquid TPU through them. The in-plane thermal conductivity (TC) of composite reaches 242 W m⁻¹ K⁻¹ with the loading of 25 vol% GF and 60 vol% CF, which is 1210 times that of pure TPU. The great improvement of TC is ascribed to the thermal conductive pathways formed by continuous GF with ultrahigh TC. The addition of CF enhances markedly the mechanical properties of composites. Bending strength and modulus of composites are 5.56 and 17.09 times that of pure TPU, respectively. The proposed design and manufacture method are facile and effective to obtain polymeric composites simultaneously with high TC and good mechanical properties. (paper)