C−N Coupling Reactions on Graphene with Aromatic Macromolecules and the Spatial Conformation of Grafted Macromolecules

Abstract

The fabrication of advanced graphene-based nanocomposites with high-performance polymers requires covalent modification of graphene with aromatic macromolecules.H erein, CÀNc oupling reactionsb etween fluorinated graphene (FG) and aromaticp olyamides containing the benzimidazole moiety are successfully achieved. The optimized conditions are presented based on the nucleophilic behavior of the CÀNc oupling reactiono ng raphene. Different from the CÀNc oupling reactionb etween two small aromatic molecules, the conformation of grafteda romatic poly-amidea fter reaction changes fromt orsional to paralleled alignment on graphene with the molecular length increment.N on-covalent interactions between graphene and aromatic polyamides result in this conformational change owingt ot he extended p systems of graphene and aromatic polyamides, and the synergistic effect of covalent and noncovalenti nteractions is put forward. As ac onsequence, graphene dispersibility is greatlye nhanced in the solution of aromatic polyamide.

Interfacial π–π Interactions Induced Ultralight, 300 °C-Stable, Wideband Graphene/Polyaramid Foam for Electromagnetic Wave Absorption in Both Gigahertz and Terahertz Bands

“…Then, what leads to such a macromolecular orientation phenomenon for PA along the graphene sheet? A highly possible reason is the interfacial π–π interaction. , As is well known, a high density of benzene rings in PA macromolecules could form strong π–π interactions with graphene, , which could induce dramatic effects on the properties of the composites. Comparing those three stages in the preparation of composite foam, the only difference is the reduction degree of graphene, as reflected by the I D / I G values obtained from Raman spectra (Figure e).…”