Biobased and Recyclable Epoxy Composite with High Thermal Conductivity Based on Disulfide Exchange

The demand for thermal management materials is growing due to the rapid development of electronics. However, most thermally conductive composites cannot be recycled after use, resulting in a significant waste of resources and environmental pollution. In this work, a recyclable and reprocessable high thermally conductive epoxy resin composite is developed by utilizing biobased raw materials epoxidized soybean oil (ESO). The recyclability and reprocessability are achieved by disulfide exchange. The thermal conductivity of the matrix is improved by adding boron nitride (BN) fillers, which are further compelled to be aligned in the matrix to fabricate a highly thermally conductive bulk epoxy composite in an oriented direction. Results reveal that a thermal conductivity of 3.01 W m–1 K–1 is achieved in the composites with aligned arrangement BN, which is increased by 32.6% compared to composites with randomly distributed filler. Moreover, due to the disulfide exchange, the matrix can be decomposed under chemical conditions, which allows for the filler to be completely separated through physical filtration for reuse, completing the closed-loop recycling of the filler. This study provides an effective and facile method for the fabrication of biobased thermal management materials and also offers paramount potential for sustainable development.