Characteristics of nylon 6,6/nylon 6,6 grafted multi-walled carbon nanotube composites fabricated by reactive extrusion

Nylon 6,6 composites containing nylon 6,6 grafted multi-walled carbon nanotubes (nylon 6,6-g-MWCNT) were fabricated from nylon 6,6 and acyl chloride grafted MWCNT (MWCNT–COCl) by reactive extrusion. MWCNT–COCl was produced by reacting acid-treated MWCNTs with thionyl chloride. Formation of nylon 6,6-g-MWCNT by reactive extrusion was confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and scanning electron microscopy. To quantify the interfacial adhesion energies of nylon 6,6 and pristine and functionalized MWCNTs, the contact angles of cylindrical drop-on-fiber systems were determined using the generalized droplet shape analysis. The interfacial adhesion energy of the nylon 6,6/nylon 6,6-g-MWCNT composite was twice that of the nylon 6,6/pristine MWCNT composite. Nylon 6,6-g-MWCNTs exhibited excellent dispersion in the composite, whereas pristine MWCNTs exhibited poor dispersion when composite films were prepared by solvent casting. The reinforcement level of the composite increased with increasing MWCNT content. Among the composites examined, the nylon 6,6/nylon-g-MWCNT composite with a fixed MWCNT content exhibited the highest level of reinforcement.