Ti3C2Tx MXene modified polyethylene fibers for enhancing interface properties of strain-hardening cementitious composites

MXene is a new two-dimensional transition metal carbide/nitride with remarkable hydrophilicity, which has been widely applied in multifunctional coatings. In this study, Ti3C2Tx MXene was synthesized by LiF/HCl solution etching of Ti3AlC2 and used to modify the surface of polyethylene (PE) fiber, enhancing the interfacial properties between fiber and matrix and further improving the tensile properties of strain hardening cementitious composites (SHCC). The tensile stress and strain of SHCC incorporating the MXene-coated PE (MXene@PE) fiber increased by 18.73 % and 93.60 %, respectively, accompanied by reduced crack width and crack spacing. Single fiber pullout results showed that the frictional bond strength increased by 71.35 % due to the strong chemical bond between fiber and matrix. The microstructure of MXene@PE fiber and bonding properties were characterized by SEM/EDS, FTIR, and XPS. The MXene was proved to have a dual effect of bonding to PE fiber and to C–S–H via covalent and hydrogen bonds.