With the rapid advancement of electronic technology, consumer electronics are becoming increasingly miniaturized and compact. Consequently, there is a growing demand for enhanced thermal management in the packaging of electronic components—driving the trend toward high-thermal-conductivity packaging materials. According to studies, for every 2°C rise in temperature, the reliability of electronic components drops by 10%. This underscores the critical need for packaging materials that can efficiently dissipate the heat generated by devices, thereby minimizing thermal-induced performance degradation and ensuring long-term device reliability.

　　Insulating thermally conductive polymer-based composites are materials that can transfer heat while maintaining electrical insulation, making them highly valuable in applications such as thermal management systems, aerospace engineering, and electronics. Table 1 lists the thermal conductivity of several polymers; as the data reveals, most polymer materials exhibit poor thermal performance. Even high-density polyethylene, which boasts relatively good thermal conductivity, achieves a thermal conductivity of only 0.44 W/(m·K). Therefore, researching and developing insulating resin-based composites with enhanced thermal conductivity is of critical practical importance.

　　Currently, there are three main approaches to enhancing the thermal conductivity of polymer materials: 1. Synthesizing polymers with inherently high thermal conductivity or incorporating thermally efficient functional groups into the molecular chains; 2. Exploring advanced polymer processing techniques and equipment to optimize the chain arrangement within the polymer, enabling it to achieve a highly crystalline structure that facilitates heat transfer via phonon conduction; 3. Adding highly thermally conductive fillers. Among these, the first two methods face significant challenges—such as complex manufacturing processes and stringent equipment requirements—which currently make large-scale production difficult to achieve. In contrast, the third approach, involving thermally conductive fillers, is widely adopted due to its simplicity, efficiency, and ease of control.

　　As a thermal conductive filler, it should meet the following basic requirements: high thermal conductivity, chemical inertness toward the polymer matrix, and excellent chemical and thermal stability. Boron nitride stands out as an ideal filler for fabricating highly insulating, thermally conductive polymers due to its low dielectric constant, high volume resistivity, and superior thermal conductivity. Consequently, BN/polymer composites have become a key research focus in the development of advanced insulating and thermally conductive polymer-based materials.

　　The properties of thermally conductive fillers/polymer composites depend on factors such as the morphology of the filler—specifically, its size, shape, and dispersion within the polymer matrix—all of which significantly influence the thermal conductivity of the polymer. By combining different forms of boron nitride as fillers, polymer composites can achieve outstanding thermal performance.