Hexagonal boron nitride (BN) platelets, also known as white graphite, are often used to improve the thermal conductivities of polymeric matrices. Due to the poor interfacial compatibility between BN platelets and polymeric matrices, in this study, polyrhodanine (PRd) was used to modify BN platelets and prepared functionalized BN-PRd platelets, thereby enhancing the interfacial interaction between the thermal conductive filler and polymeric matrix. Then, BN-PRd platelets were dispersed into the nitrile butadiene rubber (NBR) matrix to yield high thermally conductive composites. The presence of NC═S groups in PRd allowed the combination of PRd and NBR chains containing stable covalent bonds via vulcanization reaction. The thermal conductivity of the as-prepared 30 vol% BN-PRd/NBR composite reached 0.40 W/mK, representing an increment of 135% over pure NBR (0.17 W/mK). In addition, the largest tensile strength of NBR composite containing 30 vol% BN-PRd platelets was 880% times of pure NBR. The 30 vol% BN-PRd/NBR composite also displayed a relatively high dielectric constant (9.35 at 100 Hz) and a low dielectric loss tangent value (0.07 at 100 Hz), indicating their usefulness as dielectric flexible materials of microelectronics. In sum, the simplicity and good efficiency of formation of covalent bonds between boron nitride and rubber chains look very promising for large-scale industrial production of high thermally conductive composites.

中文翻译：

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通过在氮化硼和橡胶链之间形成共价键来增强聚合物复合材料的导热性和机械性能

六方氮化硼 (BN) 片晶，也称为白石墨，通常用于提高聚合物基体的热导率。由于BN片晶与聚合物基体的界面相容性较差，本研究采用聚罗丹宁（PRd）对BN片晶进行改性，制备功能化BN-PRd片晶，从而增强导热填料与聚合物基体之间的界面相互作用。然后，将 BN-PRd 薄片分散到丁腈橡胶 (NBR) 基体中以产生高导热复合材料。N 的存在PRd 中的 C=S 基团允许 PRd 和含有稳定共价键的 NBR 链通过硫化反应结合。所制备的 30 vol% BN-PRd/NBR 复合材料的热导率达到 0.40 W/mK，比纯 NBR (0.17 W/mK) 增加了 135%。此外，含有 30 vol% BN-PRd 片晶的 NBR 复合材料的最大拉伸强度是纯 NBR 的 880%。30 vol% BN-PRd/NBR 复合材料还显示出相对较高的介电常数（100 Hz 时为 9.35）和低介电损耗角正切值（100 Hz 时为 0.07），表明它们可用作微电子的介电柔性材料。总之，氮化硼和橡胶链之间形成共价键的简单性和良好的效率对于高导热复合材料的大规模工业生产非常有前景。