Abstract Polymer nanocomposites for thermal management applications, such as flexible electronics, sensors, and stretchable devices, require enhanced thermal conductivity while maintaining mechanical flexibility. However, achieving a balance between thermal and mechanical properties remains a significant challenge, as improving one property often compromises the other. In this study, we design and fabricate elastic, compliant, and moldable polymer blend nanocomposites with enhanced thermal conductivity. The nanocomposite system comprises dynamically vulcanized rubbery polyisoprene (PI) as the continuous matrix and stiffer polystyrene (PS) as the dispersed phase, along with two-dimensional (2D) boron nitride (BN) as the thermally conductive filler. The PI matrix is selectively crosslinked, whereas the PS phase remains non-crosslinked, making the composites processable. BN is uniformly distributed in both polymer phases to facilitate effective thermal conduction. A hot-pressing step following extrusion aligns the 2D BN predominantly in the in-plane direction, inducing anisotropy in both thermal conductivity and elastic modulus. At a BN loading of 40 vol%, the in-plane thermal conductivity increases by approximately sevenfold and the cross-plane thermal conductivity by twofold compared to the unfilled PS/PI blend. Similarly, the in-plane elastic modulus is enhanced by approximately 10 times and the cross-plane modulus by about 2.5 times. The overall modulus remains below 8 MPa across all compositions, ensuring that the composites remain soft and compliant. We anticipate that the materials developed in this study can be modified for the next generation of thermally conductive yet mechanically flexible applications.
Pokhrel et al. (Mon,) studied this question.