Hierarchical Synergistic Construction of Zro₂ Nanoparticles and (3-Mercaptopropyl)Trimethoxysilane on Carbon Fiber Surface for Enhanced Interfacial Properties of Carbon Fiber /Norbornene-Polyimide Composites

Abstract

To enhance the interfacial bonding performance of carbon fiber (CF) reinforced norbornene-polyimide (PI-NA) composites (CF/PI), this study developed a simple surface modification method combining hydrothermal treatment and chemical grafting. The method successfully prepared CF/nano-species/polymer multi-scale reinforced materials, significantly enhancing interfacial strength while providing a simple and efficient composite preparation strategy. The research employed a synergistic approach of mechanical interlocking and chemical bonding by loading ZrO2 nanoparticles (ZNP) and (3-mercaptopropyl)trimethoxysilane (MPS) onto CF surfaces. ZNP improved the fiber's surface roughness, enhancing mechanical interlocking between fibers and resin. Additionally, the hydroxyl-rich surfaces of ZNP anchored on the fiber surfaces served as secondary reaction sites, facilitating the effective grafting of MPS onto the fiber surfaces. Subsequently, the thiol groups (-SH) in MPS formed chemical bonds with the norbornene groups in PI-NA through click chemistry reactions. Experimental results showed that under hydrothermal conditions at 180 °C, treating CF first with 1.5% ZrOCl2·8H2O solution for 18 hours, followed by 0.5% MPS hydrolysis solution for 2 hours, resulted in composites with interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) of 73.29 MPa and 96.0 MPa, representing increases of 37.43% and 45.01% respectively compared to untreated CF composites. This process is simple, efficient, and cost-effective, showing excellent potential for industrial applications.

Keywords: Carbon fiber, PI-NA, ZrO2 nanoparticle, MPS, interfacial strength