To meet the non-removable application scenarios of most integrated electronics, the development of polymer-based packaging materials possessing superior thermal conductivity and self-healing characteristics simultaneously is necessary. However, on account of the complexity of composite structure and composition , its self-heal remains a formidable challenge. Herein, we have designed a self-healing and thermally conductive bi-functional polyurethane composites with Diels-Alder structure (PUDA) and silver nanowires (AgNWs). The hydrogen-bonding network at the interface of AgNWs and PUDA facilitated the dispersion of AgNWs in the matrix, which endows the composites with desirable thermal conductivity . Incorporating 3, 6, 9, 12, and 15 wt% of AgNWs into PUDA leads to increases in thermal conductivity of 33%, 104%, 154%, 321%, and 371%, respectively. In particular, the novel composites incorporated 12 wt% AgNWs exhibited the most efficient balance between self-healing efficiency and thermal conductivity performance. The thermal conductivity of PUDA/AgNWs with 12% of AgNWs content is 1.01 W/mK, which is 4.8 times that of PUDA (0.21 W/mK). After two reconstitution cycles, the thermal conductivity of PUDA/AgNWs-12 was restored to 85%. This study demonstrates the successful preparation of composites possessing both desirable thermal conductivity and self-healing capabilities, rendering them suitable for use as thermal interface materials in thermal management systems and flexible electronics applications.
A novel polyurethane resin containing acrylate function and Diels-Alder (DA) structure was synthesized, with potential thermal reversibility and UV curable properties. The UV curing process was monitored by Fourier transform infrared spectroscopy (FTIR), which indicated that the DA structure was stable during curing process and the final acrylate C C conversion is 82.5%. The cured film exhibited good repeatedly thermal reversibility. The retro-Diels-Alder (rDA) reaction of the cured film occurred at temperatures higher than 85.5 °C and was obviously accelerated by increasing temperature, which was confirmed by the results of FTIR, differential scanning calorimeter (DSC) and dynamic thermomechanical analysis (DMA). The cured film displayed acceptable thermal stability up to 278.3 °C according to the thermal gravimetric analysis (TGA) results. Finally, a cured film with excellent physical properties was obtained.
危险品化学品经营许可证（带存储）