Ice template method assists in obtaining carbonized cellulose/boron nitride aerogel with 3D spatial network structure to enhance the thermal conductivity and flame retardancy of epoxy-based composites

In the field of modern microelectronic packaging materials, there is a great need for polymer-based composites with both excellent thermal conduction and flame retardancy properties. However, the enhancement efficiency of polymer-based composites is actually lower than the theoretically predicted values due to the phonon scattering in polymer matrix and the interfacial thermal resistance (Ritr) caused by the lack of continuous thermal conductive paths between the polymer matrix and fillers. In this work, a novel epoxy-based composite is reported by constructing 3D carbonized cellulose/boric acid ball mill modified boron nitride aerogel (CCA/m-BN) network using ice-templated combined with a customized directional freezing mold approach, and then infiltrating it with epoxy (EP) matrix. The fabricated CCA/m-BN/EP exhibits a significantly enhanced thermal conductivity (TC) up to 2.11 W/(m K) at a low m-BN loading of 9.6 wt% compared to that of pure PE (0.19 W/(m K)) and traditionally blended m-BN/EP composite (0.40 W/(m K)) as well that of CCACT/m-BN/EP composite (1.54 W/(m K)) obtained with ordinary directional freezing mold. In addition, CCA/m-BN/EP also exhibited a desired flame retardancy performance with considerable reductions being seen in peak of total heat release (THR) and total smoke production (TSP) compared with other composites. The obtained CCA/m-BN/EP composite with high TC and good flame retardancy properties is a highly prospective candidate as next-generation thermal dissipating material for electronic devices.Graphical abstract