Abstract:

In order to improve the bonding performance between aramid fiber and resin matrix, the aramid fiber was modified by cold plasma in nitrogen gas.  The surface morphology, chemical composition, surface wettability and surface energy aging properties of the aramid fibers treated by nitrogen cold plasma were studied with the increase of deposition time. The fibers were observed by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and contact angle meter. The results show that the surface roughness of the fiber obviously increases after within 24 h treatment, the content of C on the fiber surface decreases and the contents of the N and O increase. The wettability changes from the hydrophobicity to hydrophilicity. The surface energy is improved. As time increases, the fiber surface remains rough. Non-polar group C—C and C—H increase, the polar group C—N, C—O and NH—C = O decrease, and the surface energy gradually reduces with the increase of contact angle, and finally tend to be stable. After 28 d, in comparison with the untreated fiber, the contact angle of the treated fibers reduces by 27.8°, and the surface energy increases by 87 %. This indicates that the cold plasma etching and modification of the surface are permanent.

Key words: cold plasma treatment, fiber modification, aramid fiber, aging property