Effect of spinning process on the properties of T800 carbon fiber and its reinforced composite

The surface conditions of the two different T800 carbon fibers by the wetting (T800HB) and the dry jet-wetting spinning processes (T800SC) were characterized and analyzed by scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscope (XPS) and contacting-angle measuring instrument. The mechanical properties of their multifilaments, NOL rings and unidirectional laminates were evaluated by universal material testing machine. Results show that the surface of T800HB by wetting process is rougher, while the surface of T800SC by dry jet-wetting process is more chemical-active. Both chemical interaction and mechanical engagement between fiber and resin matrix result in the similar interlaminar shear strength (ILSS) of T800HB and T800SC. However, when the composite is damaged, the interfacial bonding of T800HB/resin seems tighter dominated by the mechanical engagement, leading to brittle fracture feature of T800HB reinforced composite, while T800SC reinforced composite exhibits ductile fracture feature with weaker interfacial bonding. In addition, the tensile strength of filament of T800SC is higher than that of T800HB. Accordingly, the tensile strength of NOL ring and unidirectional laminate composite of T800SC are higher than those of T800HB. Therefore, in combination of mechanical properties of carbon fibers by two kinds of spinning processes and their reinforced composites, as well as their fracture features, compared with T800HB, T800SC is more suitable to be the reinforcement of the composite fabricated by filament winding process.