Effects of three types of T700 carbon fiber on the mechanical properties of their composites with bismaleimide resin

Three types of T700 carbon fibers, A-3K, A-12K and T700SC-12K, were used as reinforcements of carbon fiber/bismaleimide resin composites. The surface roughness and fuzziness of the three fibers, their damage in the preparation of the prepreg and the mechanical properties of the final composites were compared. Results indicate that the surface roughness and fuzziness of A-3K and A-12K produced using a wet-spinning method are larger than that of T700SC-12K from a dry-jet wet-spinning method. The tensile strength retention ratio in the direction parallel to the fiber axis from fibers to composites of T700SC-12K is higher than those of A-3K and A-12K, owing to the smooth surface, best wear resistance and the minimum damage produced during the preparation of the prepreg for the former. The decreasing order of tensile strength in the direction parallel to the fiber axis of the composites is T700SC-12K, A-3K and A-12K. The interfacial bonding for the composites from A-3K and A-12K is much better compared with T700SC-12K because the former two have stronger mechanical anchoring between fibers and resin matrix than the third.