Changes in Adhesion, Physico-Chemical and Morphological Properties of Torayca~(~R) T-700G Carbon Fibers

摘要

In this study, XPS results on the Torayca T-700G carbon fibers indicate that oxygen and nitrogen contents of the fiber surface are 7-9% and 3% in the UT fiber, and 15-17% and 6-7% in the ST fiber. The values in the ST fiber are relatively higher compared to those of other carbon fibers. The dispersive and polar components of fiber surface free energy computed from the advancing dynamic contact angle are 36.3 mJ/m~2 and 3.9 mJ/m~2 in the UT and 38.9 mJ/m~2 and 11.7 mJ/m~2 in the ST fiber, respectively. STM images indicate that the UT and ST fiber have rippled surface microstructures consisting of oval-shaped grains, which form a ribbon-like structure extending along the fiber axis in twisting each other. Surface treatment roughens ST fiber surface giving 1.5 times and 1.4 times increments in average surface roughness and surface area compared with the UT fiber. The single fiber fragmentation tests demonstrate that the adhesion increases as a result of surface treatment but the fibers have lower adhesion to the epoxy resins than other PAN-based high strength carbon fibers. Adhesion of the carbon fibers to polycarbonate is increased with the increase of the consolidation temperature and the average molecular weight.