Simultaneously enhanced thermal conductivity and mechanical properties of PP/BN composites via constructing reinforced segregated structure with a trace amount of BN wrapped PP fiber

[Display omitted] •Constructing fiber reinforced segregated structure.•BN orient along the fiber surface forming robust thermally conductive network.•Simultaneously enhanced thermal conductivity and mechanical properties. Segregated structure with continuous filler network but isolated matrix is a classic prototype to increase the thermal conductivity (TC) of the composites. However, such prototype only finds limited applications due to both the poor mechanical properties originated from the discontinuity of the polymer matrix and the mediately improved TC of the continuous filler network arising from the random contact of the fillers. In this work, a reinforced segregated structure in which the continuous phase is made with boron nitride (BN) wrapped a trace amount of PP fiber (PF), is first proposed in order to enhance the TC and mechanical properties simultaneously. In such reinforced segregated structure, BN aligns on the surfaces of PF thus forms a long-range ordered, high thermal conductive pathway. As expected, an enhancement of 244%, 133% and 103% in the TC, elongation at break and tensile strength of the composite with reinforced segregated structure are successfully achieved compared with typical segregated structure. Therefore, this work offers some new insights into the design of a segregated structure to balance the TC and mechanical properties.