Nylon 6,6/graphene nanoplatelet composite films obtained from a new solvent

Solution processing of aliphatic polyamides (nylon) is quite challenging due to the fact that only a few solvents, such as formic acid and cresol, dissolve nylon. In general, polyamide 6,6 (nylon 6,6) is dissolved in formic acid to produce porous membranes or electrospun fibers. Herein, we propose for the first time a mixture of trifluoroacetic acid (TFA) and acetone that dissolves nylon 6,6, resulting in crystalline and non-porous films. Furthermore the same mixture of solvents was proved to be an excellent co-solvent for graphene nanoplatelets that were homogeneously dispersed in the solutions to produce reinforced nylon 6,6 polymer composites. The dispersion of the nanoplates in the polymer solution was found to be very stable over time. The mechanical and electrical properties of the developed composites were studied as a function of filler content. The Young's modulus of the nylon 6,6 films increases more than two times upon the addition of the nanoplates. Furthermore, the flexible composites exhibit semiconducting behavior, with their electrical conductivity reaching 10−2 S cm−1 for 20 wt% graphene nanoplatelet concentration.