Self-assembled nano-polymers modified water-based sizing agent for enhancing the dual interfacial properties of carbon fibre/epoxy resin composites

The dual interface-enhanced sizing agents are prepared to simultaneously exhibit high surface roughness and high interfacial wettability through self-assembled nano-polymers. Five self-assembled nano-polymer modified water-based sizing agents (NPSAs) with various cross-linking structures are synthesized in this paper. It is demonstrated strong characteristics of homogeneous particle size in the 90–200 nm range and heat stability below 200 °C. NPSAs significantly improve the CF surface properties of both surface roughness and surface energy, with reached high values of 13.89 nm and 40.22 mN m-1. Notably, the interlaminar shear strength (ILSS), flexural strength, and fracture toughness (KIC) of CF/ER composites sized by NPSAs are enhanced to 70%, 51%, and 120% compared with the unoptimized composite, respectively. The NPSA reinforcing mechanism, enhancing interfacial properties of CF/ER composites in the interfacial interlocking and adhesion ability, was clarified by the coefficient of thermal expansion (CTE1). Additionally, NPSAs have the advantage of being applicable for simple one-pot synthesis methods, and secondly, no toxic solvents were used.