Abstract:

The surface of para aramid fiber (Twaron) is required to be modified to improve the bonding property between aramid fiber and matrix material. So the research of phosphorylated surface modification of para aramid fiber by dilute phosphoric acid which was concentrated gradually under high temperature has been done. The research results showed that the method of dilute phosphoric acid concentrated under high temperature could modify aramid fiber effectively; XPS analysis showed that surface modification of aramid fiber by concentrated dilute phosphoric acid can introduce a large amount of phosphorus; SEM analysis showed that the surface of fiber changed from smooth to a slightly rough after modification; infrared spectrum analysis indicated that -P-OH was introduced to the surface of aramid fiber through modification, 31P-NMR analysis indicated that diphosphate groups were introduced in the structure of the modified aramid fiber; X ray diffraction and thermal gravity analysis showed that the crystal structure of modified aramid fiber didn’t change, the crystallinity of fiber increased and it maintained good thermal stability ; the modified aramid fiber kept good mechanical properties in low concentration of phosphoric acid. The technique of dilute phosphoric acid concentrated under high temperature has the advantages of short process、high velocity of modification、low cost, and has a good application prospect.