Carbon nanotubes-intervened interface design of quartz fiber/polyurethane composite fibers towards improved mechanical properties

Inspired by the Xanthium fruit-like structure, a hybrid hardness and softness structure of carbon nanotubes (CNTs) and polymer chains is considered to be a promising hybrid grafting material. The distributed hard CNTs and soft polymer chains (γ -mercaptopropyl triethyl silane, MPTS) increase the surface roughness of short quartz fibers (QFs), forming a percolated network throughout the surrounding polyurethane (PU) matrix, thereby improving the interfacial interaction between QFs and PU. The modified QFs demonstrate improved interfacial adhesion, higher fiber surface energy, and greater interfacial area failure resistance. The composite fibers exhibited better interfacial adhesion owing to the multi-scale interface structure by CNT@MPTS. In comparison to the unmodified QFs, the interfacial shear force increased by 50.59 %, respectively. Enhancements in the mechanical properties, load transfer in the interface phase, local stress elimination, and inhibition of interphase crack are also brought about by the synergistic effect of CNT and MPTS. The tensile strength of CNT@MPTS modified QFs/PU composite fibers (8% [email protected] %QFPU) rose by 16.72 %. These results indicate a promising route toward developing continuous QFs-based composites with applications as textile-reinforced polymer composites.