Improvement in interlaminar shear strength and flexural properties of carbon fiber/epoxy composite using surface-modified carbonate calcium

In the presen study, the effect of carbonate calcium (CaCO3) loading and CaCO3 modification on the interlaminar shear strength (ILSS) and flexural properties of carbon fiber/epoxy composite was investigated. Firstly, CaCO3 was functionalized with 3-glycidoxypropyltrimetoxysilane (3-GPTMS), which was confirmed by Fourier transform infrared (FTIR) spectroscopy. The CaCO3 nanoparticles were infused into carbon fiber/epoxy composite at various contents (0.5, 1, 3, and 5 wt.% with respect to the matrix) using ultrasonication and standard mixing routes. The results of mechanical tests showed that adding 3 wt.% silanized-CaCO3 improved the ILSS, flexural modulus, and flexural strength of the carbon fiber/epoxy composite by 25%, 36%, and 27%, respectively. Micrographs of fracture surface analysis confirmed that the carbon fiber/matrix interfacial bonding can be improved significantly by incorporating the silanized CaCO3 nanoparticles. The ILSS, flexural modulus, and flexural strength of the silanized CaCO3/carbon fiber/epoxy composite were greater than that of unmodified CaCO3/carbon fiber/epoxy composite. These results indicated that the silane-modified CaCO3 dispersion within the matrix of fibrous composites plays a key role to achieve high performance composites.