UHMWPE fibers reinforced gradient structure to break the thermal-dielectric-mechanical trade-off in high filled polyethylene.

In view of the diversified demands for thermal management materials in soaring developments of electrical systems, the high thermally conductive composites often suffer from their poor mechanical properties and electrical insulation. Targeting at enhancing simultaneous thermal conductivity, dielectric and mechanical properties, the fibers reinforced gradient structured polyethylene-based composites consisting of ultrahigh molecular weight polyethylene (UHMWPE) fiber layer and hybrid-filled layer are proposed and successfully prepared by simple overlapping-hot pressing. The fibers collaborated with gradient arrangement of hybrid-filled layer in modulating the temperature, electric and stress field distribution. The resultant as-designed composites exhibit excellent thermal conductivity of 0.91 W/(m·K), ultrahigh tensile strength of 104.7 MPa and superior breakdown strength of 161.5 kV/mm, which are increased by 18%, 1374% and 37% than those of the homogeneous composites, respectively. This work provides a new strategy for manufacturing high-performance polymer-based composites. [Display omitted] • A new strategy was proposed to design PE-based composites with high thermal-dielectric-mechanical performances. • The UHMWPE fibers reinforced gradient structure was constructed through simple overlapping-hot pressing. • The structured composites have ultrahigh tensile strength, superior breakdown strength and high thermal conductivity. • The fibers collaborated with hybrid-filled layer in modulating the temperature, electric and stress field distribution. [ABSTRACT FROM AUTHOR]