High-Performance Basalt-Fiber-Reinforced Laminated Composites: Free of Fiber Surface Modification and Sizing Agent

Thanks to the advantages of synthesis-free, excellent mechanical properties and heat resistance, basalt fibers (BFs) have been viewed as a new generation of reinforcement, which is a promising substitute for synthetic glass fibers. However, achieving satisfied comprehensive performances for BF-reinforced composites is still a great challenge because of the poor interfacial compatibility of BF toward conventional matrix resins. In this study, a melamine–hexamethylenediamine (MH) thermoset was used for the first time as the matrix of BF-reinforced laminated composites. With no surface modifications performed and no sizing agent used, the BF-reinforced MH composites (BFRMH) exhibited excellent comprehensive performances. Specifically, the BFRMH composites have heat deflection temperature above 300 °C, flexural strength up to 750 MPa, and interlaminar shear strength above 68 MPa. Particularly, the BFRMH composites are highly resistant to extreme temperature as enhanced mechanical strength and toughness were observed at 77 K, and 78% flexural strength retained even after treated at 798 K. These performances are far superior to that of reported BF-reinforced composites and of the glass-fiber-reinforced composites. In addition, the excellent chemical resistance, insulating property, conductivity, as well as flame retardancy (UL94-5VA) suggest that the BFRMH composites are potential materials for electrical and electronic applications. The results of this work revealed the great potential and suitability of the MH resin matrix for fabricating BF-reinforced composites, due to its excellent interfacial compatibility.