Self-assembly of diazonium-modified boron nitride nanosheets and glass fibre: A strategy synergistically improving mechanical, insulating and thermal properties of glass fibre reinforced polymer composites

Glass fibre reinforced polymer composite with excellent comprehensive properties are extensive demanded in power industry attributed to the development of power equipment reliability. However, how to realize the synergistic control of mechanical, insulating and thermal properties of composites in industry needs further exploration. Herein, glass fibre reinforced polymer with high thermal conductivity, excellent mechanical and breakdown strength has been successfully prepared based on a highly scalable ‘nanofillers self-assembling’ method. Boron nitride nanosheets modified via diazo coupling were introduced as the self-assembled layer of glass fibre to improve the insulation properties of the composite. By adjusting the number of self-assembly layers, the synergistic improvement of composite properties is realized. Specifically, the flexural and tensile strengths of the modified composites reached 379.45 and 303.49 MPa, respectively, about 16.95% and 23.47% higher than untreated sample. Moreover, the breakdown strength of self-assembled composites has been promoted by 7.02 and 26.51% compared with untreated one and the sample reinforced by polydopamine modified glass fibres. Simultaneously, thermal conductivity of modified composites has been enhanced from 0.31 to 2.12 W/(m·K) due to highly thermally conductive boron nitride nanosheet and the transport process of organic semiconductor carriers and phonons. Therefore, this work provides a feasible method for the preparation of composites with high comprehensive properties, and provides a reference for the preparation of reliable power equipment.