Concurrent enhancement of dimensional stability and thermal conductivity of thermoplastic polyamide 12T/Boron nitride composites by constructing oriented structure

Excellent thermal management property and high-temperature dimensional stability are very important for the materials applied in the electronic devices. In this study, high temperature resistant PA12T was applied as the matrix, and PA12T/BN composites with oriented structure were fabricated by the injection molding method. Morphology, thermal conductivity, thermal expansion property and mechanical properties of the composite were systematically investigated. Results demonstrate that when the content of BN is 40 wt%, the in-plane thermal conductivity and thermal expansion coefficient of the composites are 6.5 W/(m·K) and 36 ppm/°C, respectively, which are 4 times higher and 80% lower than those along the through-plane direction. Meanwhile, the thermal expansion behavior and mechanism of the composite with oriented filler structure are well revealed by finite element analysis, and the simulated results will provide important guidance for the design and application of the composite. Furthermore, by using the PA12T/BN composite with oriented structure as the substrate of printed circuit board, temperature gradient as well as thermal stress inside the device can be well controlled. Therefore, the PA12T/BN composite has great potential in the application as the substrate or packaging materials of electronic devices.