Improving Compressive Strength of Aramid Fiber by Introducing Carbon Nanotube Derivates Grafted with Oligomers of Different Conformations and Controlling Its Alignment

Abstract

Low compressive strength of aramid fiber is one of the most prominent obstacles for its application as a strengthening material. Herein, based on nucleophilic reaction of CF bonds, fluorinated carbon nanotube (FCNT) derivates grafted with oligomers of different conformations are prepared to modify (Poly‐p‐phenylene‐benzimidazole‐terephthalamide) (PBIA) fiber. CF bonds of FCNT can react with benzimidazole units and terminal amino groups of PBIA oligomers. Therefore, FCNT derivates grafted with oligomers of different conformations can be obtained. Then, the FCNT derivates are blended with PBIA solution to prepare PBIA/FCNT composite fibers. Compressive strength is improved by nearly 34.7% and 107% for the fiber modified by FCNT derivates grafted with oligomers of parallel and vertical conformations, respectively. It is found that FCNT derivates grafted with oligomers of vertical conformation may be forced to be aligned vertically to axis of the fiber, which is more beneficial to improve lateral interaction and compressive strength of the fiber.