Modification of carbon fibers surfaces with polyetheramines: The role of interphase microstructure on adhesion properties of CF/epoxy composites

Interface construct plays a vital role in developing superior mechanical performance of carbon fibers (CFs)/resin composites. Herein, a facile approach for incorporation of polyetheramine (PEA) onto CFs surface by covalent bond (CF-g-PEA) was proposed, and compared to the adsorption one via Van der Waals' force (CF-c-PEA). FTIR, X-ray photoelectron spectroscopy, Raman spectra, scanning electron microscopy, atomic force microscopy, dynamic contact angle analysis, single fiber tensile testing, and interfacial shear strength were carried out to characterize the CF reinforcements and composites. Experimental results showed that both of coating and grafting PEA on CFs increased the polarity, wettability, roughness of CF surface, and interfacial shear strength, especially CF-g-PEA, which indicated covalent bond interaction can combine more PEA on CF surface than that of Van der Waals. While single fiber tensile strength of CF-c-PEA increased due to the structure of CF without destruction. Meanwhile, the reinforcing mechanisms and interfacial failure modes of composites were also explored. The results suggest that the interphases between the CFs and resin matrix can be adjusted by varying the bonding natures between CF and grafted modifiers, thereby offering a new route for appropriate designing and development of CF-based composite materials. POLYM. COMPOS., 39:E2346-E2355, 2018. (c) 2017 Society of Plastics Engineers