New simple strategy for improving interfacial adhesion of basalt fiber composites by adhering bio-based β-cyclodextrin on fiber

Though basalt fiber has excellent mechanical properties and attractive green feature, the ultralow interfacial strength of fiber-to-polymer greatly limits its application. Herein, investigation into the first use of β-cyclodextrin (β-CD) and silane coupling agent as surface modifier for basalt fiber by dint of chemical grafting strategy was presented. The resulted fiber was discovered to provide the growth of 61.5% in fiber-to-epoxy adhesion relative to untreated basalt fibers in epoxy. The change in interfacial strength is associated with the improved epoxy wetting behavior and increased covalent interactions contributed by the unique conical hollow ring architecture of β-CD that offers more acting sites to be linked and accommodated with more silane coupling agents for subsequent chemical crosslinking and physical entanglement with greater epoxy molecules. Additionally, the crack deflection by "rigid" β-CD at interphase dissipates more energy. First proved superiority of β-CD for strengthening the interphase in this work paves the way for developing green and high-performance fiber composites, responding well to the sustainable development in engineering.