Fabrication of carbon fiber grafted with acyl chloride functionalized multi-walled carbon nanotubes for mechanical reinforcement of nylon 6,6

Abstract Carbon fiber (CF) grafted with acyl chloride functionalized multi-walled carbon nanotube (MWCNT), or (MWCNT-CF), was prepared by the reaction of aminopyrene (AP) adsorbed on CF (CF-AP) and 1-pyrenebutyric chloride (PBC) adsorbed on MWCNT (MWCNT-PBC). It is introduced that four kinds of PA66 composites, containing single incorporation of pristine CF, two-component incorporation of pristine CF and pristine MWCNT, two-component incorporation of PBC adsorbed CF (PBC-CF) and MWCNT-PBC, and single incorporation of MWCNT-CF were fabricated by melt extrusion, and their fatigue life and tensile and interfacial properties were explored. The residual PBC on the MWCNT of MWCNT-CF was reacted with the amine end group of PA66 during the melt extrusion process to produce PA66 grafted MWCNT-CF. When the content of total carbon fillers was fixed, PA66/MWCNT-CF and PA66/CF-PBC/MWCNT-PBC composites exhibited better fatigue life and tensile strength than PA66/pristine CF/pristine MWCNT composites owing to improved interfacial adhesion between PA66 and carbon fillers. Among the composites examined, the highest fatigue life and tensile strength of the PA66/MWCNT-CF composite were owing to the hierarchical structure of MWCNT-CF and optimal interfacial adhesion caused by chain entanglement between the PA66 grafted to MWCNT-CF and matrix PA66.