Alleviating interfacial thermal residual stress of carbon fiber-reinforced composites by molecular pulley effect of aldehyde-functionalized polyrotaxane

Herein, to alleviate interfacial thermal residual stress (ITRS) while improving the interfacial toughness and strength of carbon fiber reinforced polymer composites (CFRPs) the aldehyde-functionalized polyrotaxane (afPR) was synthesized and incorporated into naphthalenediimide (NDI) at the CFRP interphase. The formation of afPR was confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR). Unsized CFs (uCF), NDI modified CFs (NCF), and the CFs (N0.5afPR-CF) modified by NDI with 0.5 wt ratio of afPR were prepared and characterized. The chemical activity and roughness of N0.5afPR-CF were increased. N0.5afPR-CF/EP exhibited a 76.14 % enhancement in interfacial shear strength (IFSS), an enormous increase in energy absorption by 426.15 %, a remarkable increase in interfacial toughness by 342.19 %, and a significant alleviation of 73.13 % in thermal residual stress (ITRS) compared to unsized CF reinforced composites (uCF/EP), due to the molecular pulley effect of afPR. The toughening and strengthening mechanism of N0.5afPR-CF/EP had also been proposed. • Aldehyde-functionalized polyrotaxane (afPR) was prepared for composite interphase. • Interfacial shear strength and toughness were highly improved by afPR. • Interfacial thermal residual stress was significantly alleviated by afPR. • The molecular pulley effect of afPR improved the properties of composites. • AfPR shows promise for optimizing properties of carbon fiber composite interphase.