Control of a Dual-Cross-Linked Boron Nitride Framework and the Optimized Design of the Thermal Conductive Network for Its Thermoresponsive Polymeric Composites

With the development of polymer-based composite materials technologies and the continuous expansion of its application scale, the research focus has shifted from performance and quality to multifunctionality. Conventional thermally conductive composites are static and passive. Thermoresponsive polymeric composites are dynamic and active; they are able to perceive changes in ambient temperature and exhibit simple and direct responses, which have attracted considerable attention. Herein, thermoresponsive polymeric composites were achieved using an elastic boron nitride framework (BNF) as the architecture and a phase-transition matrix for freezing temporary shapes. We use molecular simulation guiding to control the dual-cross-linked network that is based on its stable chemical bond as permanent cross-linking and tunable composition of the hydrogen bond as recoverable cross-linking. The resulting BNF exhibited attractive elasticity and high compressive strength (0.04 MPa). In addition, we optimized the design of the thermal conductive network to obtain thermoresponsive polymeric composites with their own good thermal conductivity and thermal transfer capability. The obtained thermoresponsive polymeric composites have good heat dissipation (Delta T-max = 10 degrees C), indicating temperature capability through the self-shape change. This study paves the way to fabricate multifunctional composites and, through materials structural design and performance regulation, promote the development of heat dissipation materials.