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.

Poly(3-hydroxybutyrate), a green polymer originating from prokaryotic microbes, has been used to prepare composites with graphene nanoplatelets (GnP) at different concentrations. The films were fabricated by drop-casting and were hot-pressed at a temperature lower than their melting point to provide the molecular chains enough energy to reorientate while avoiding melting and degradation. It was found that hot-pressing increases crystallinity and improves mechanical properties. The Young’s modulus increased from 1.2 to 1.6 GPa for the poly(3-hydroxybutyrate) (P(3HB)) films and from 0.5 to 2.2 GPa for the 15 wt % P(3HB)/GnP composites. Electrical resistivity decreases enormously with GnP concentration and hot-pressing, reaching 6 Ω sq^–1 for the hot-pressed 30 wt % P(3HB)/GnP composite. Finally, the hot-pressed P(3HB) samples exhibit remarkable oxygen barrier properties, with oxygen permeability reaching 2800 mL μm m^–2 day^–1, which becomes 895 mL μm m^–2 day^–1 when 15% GnP is added to the biopolymer matrix, one of the lowest values known for biopolymers and biocomposites. We propose that these biocomposites are used for elastic packaging and electronics.