Bioactive chitosan-polydopamine nanoparticles for cross-scale interfacial functionalization: Enhanced electrical insulation and mechanical properties of basalt fiber composites

The poor interfacial bonding between basalt fibers and the matrix restricts its application in the field of electrical equipment, while most interfacial treatments face the problems of technical complexity and environmental pollution. In this study, chitosan(CS) and polydopamine (PDA) nanoparticle were synergistically constructed on the surface of basalt fibers in order to form a cross-scale bioactive composite coating, the mechanism of interfacial bonding enhancement was analyzed by characterizing the wettability of basalt fibers, and electrical and mechanical property tests were carried out for the composites. The results showed that DCS-BF-2 exhibited a 53.66 % increase in tensile strength and 63.38 % increase in resin permeability compared to CR-BF, exhibiting more prominent infiltration properties. Compared to the untreated composite CR-BFRP, DCS-BFRP-2 composites showed improved insulating and mechanical properties: the breakdown strength and flashover voltage increased by 16.01 % and 31.93 %, respectively, and the dielectric loss decreased by 33.71 %. In terms of mechanical properties, the transverse tensile strength of DCS-BF-2 fiber bundles was increased by 39.62 %, the flexural strength and interlayer shear strength of DCS-BFRP-2 composites were increased by 19.50 % and 43.9 %, respectively, and the fiber-resin interfacial bonding performance was also effectively improved. • PDA and CS were constructed on the surface of BF to form a composite coating. • The permeability of resin in BF was increased by 63.38 % after coating treatment. • Composite coating enhances BF surface energy(61.77 mN/m), and it has stronger chemically active. • Composite coating makes BFRP have higher breakdown strength(28.33 kV/mm) and lower dielectric loss. • Composite coating acts as a bridge and enhances the interfacial bonding strength between BF and resin.