Polyethylene-BN nanosheets nanocomposites with enhanced thermal and mechanical properties

Polyethylene (PE) are in demand for electrical insulation and thermal management applications; however, their low mechanical and thermal properties pose major challenges. Herein, we report on novel properties of PE-boron nitride (BN) nanocomposites prepared by melt compounding followed by injection molding. The thermal and mechanical properties of silane-functionalized (sBN) and non-functionalized (pBN) PE-BN nanocomposites were studied in order to assess the role of silane functional groups at the interface of BN nanosheets and PE matrix. In comparison with PE materials, addition of 5 wt % BN nanosheets increases tensile modulus of elasticity by 37 and 42%, flexural modulus of elasticity by 24 and 30%, tensile strength by 15 and 27%, and storage modulus by 80 and 91% for pBN and sBN nanocomposites, respectively. Besides mechanical reinforcement, thermal and thermomechanical properties were evaluated for PE-BN nanocomposites. While thermal stability of PE-pBN and PE-sBN nanocomposites was comparable, coefficient of thermal expansion was decreased by 12 and 20% at 5 wt % pBN and sBN nanosheets, respectively. These polymer nanocomposites with enhanced mechanical and thermal properties can be an excellent choice for application in insulation materials, including thermal interface layers in electronic devices.