Rational construction of polyester/polydimethylsiloxane/boron nitride composite with enhanced thermal conductivity and mechanical properties

Abstract With the swift evolution of information technology, the heat dissipation of high‐power devices cannot be ignored, and the innovative polymer materials with high thermal conductivity have become the new center of relevant research. Herein, polyester/polydimethylsiloxane/boron nitride (PET/PDMS/BN) composites with excellent mechanical properties, flame retardant performance, and thermal conductivity were prepared by the method of multi‐layer coating. Firstly, boron nitride/polydimethylsiloxane (BN/PDMS) slurries were mechanically stirred and were coated on polyester (PET) fiber cloths, which later were fully immersed and wrapped up by slurries. Composites then became thick enough with multi‐layer PET fiber cloths overlapping each other. Fixated by the smooth and flat acrylic board, PET/PDMS/BN composites were obtained after curing at a certain temperature. Besides, drawbacks like sedimentation and agglomeration caused by the overwhelming quantity of fillers in traditional composites could be avoided through this process, which was beneficial for improving the thermal conductivity. The in‐plane thermal conductivity could be up to 1.99 −1 W/m·K −1 at 40 wt% filler content, and when the filler content was 60 wt%, the out‐of‐plane thermal conductivity could be 1.01 −1 W/m·K −1 , demonstrating an enhanced in‐plane orientation. Moreover, this work still succeeded in maintaining a robust structure with a high filler content, which enhanced the potential for industrial applications of composites. Highlights Raw materials are cheap, and the preparation procedure is simple and convenient. PET/PDMS/BN excels in flexibility and mechanical properties. The in‐plane thermal conductivity of PET/PDMS/BN is 1.99 Wm −1 K −1 (40 wt% BN). PET/PDMS/BN adjusts well with various roughnesses surfaces in practical usages. The synergy between thermal conductivity and flame retardancy is impressive.