An Improved Method for The Surface Treatment OfCarbon Fibers

摘要

Carbon fibers are routinely given a surface treatment so that suitable levels of adhesion can bernestablished between the fiber and the polymeric matrices. A new process has been developed thatrnrepresents substantial improvements over existing methods. In this new method, carbon fibers arernsubjected to short wavelength ultraviolet light in the presence of flowing air and ozone gas. Thernultraviolet light interacts with oxygen to create ozone and monatomic oxygen, highly reactivernchemical species which are available to react with the fibers. Additionally, the energetic ultravioletrnphotons can interact directly with the fiber surface to create favorable conditions for interaction ofrnthe carbon fiber surface with ozone and monatomic oxygen. The result of this two-fold process is thernrapid oxygenation of the fiber surface that is essential to promote favorable interactions with thernmatrix in polymer composites. This process has the additional benefit of improving the fiber tensilernstrength by more than 10%. The changes in carbon fiber surface chemistry were investigated withrnXPS. The single fiber fragmentation test was used to measure the interfacial shear strength followingrntreatment of the carbon fibers. The new [1] method produced significant improvements in fiberrntensile strength and interfacial shear strength when tested in an epoxy matrix.