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 (R-itr) 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 CCA(CT)/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.