Mechanochemical Routes to Functionalized Graphene Nanofillers Tuned for Lightweight Carbon/Hydrocarbon Composites

Abstract

Graphite exfoliation by shear‐induced dry and wet processes and especially mechanochemistry represent attractive routes to carbon nanofillers. Dry ball‐milling of graphite in a planetary mill under gas pressure is a scalable and environmentally benign one‐step process, which requires neither hazardous solvents nor tedious separate functionalization and purification steps. Gas type, pressure, and milling duration govern average particle size, shape, and functionalization. Ball‐milling under Ar yields hydroxylated spherical carbon particle agglomerates, whereas ball‐milling under CO2 affords functionalized nanoplatelets without encountering agglomeration problems and highly exothermic post‐milling reactions with air. The carboxylation of graphene nanoplatelets enhances their dispersibility in various media including polypropylene (PP) even in the absence of compatibilizers. Large amounts of carboxylated nanoplatelets are dispersed in PP without massive viscosity build‐up. Functionalized carbon nanoplatelet fillers enable tailoring of recyclable lightweight carbon/hydrocarbon composites exhibiting an improved balance of stiffness, strength, toughness, electrical, and thermal conductivity.

Recent trends in covalent functionalization of 2D materials

“…However, the versatility of environmental control during the process and additional energy supply for the chemical reaction from the ball's kinetic energy makes the ball-mill method a more versatile tool for functionalization. 456,457 As shown in Fig. 12(a), performing the ball-mill process under the desired gas or liquid environment functionalizes 2D materials with selected groups.…”

New avenues for mechanochemistry in zeolite science

“…Several studies have shown that the formation of graphene sheets can be aided by mechanochemical methods, where graphite is ball milled under specific conditions and graphene in excellent quality can be obtained. [131][132][133] Such a methodology may be equally applicable to zeolites, potentially…”

Mechanochemical Synthesis and Antimicrobial Studies of 4-Hydroxy-3-thiomethylcoumarins Using Imidazolium Zwitterionic Molten Salt as an Organocatalyst

“…In general, the advantages of mechanochemical approaches are no requirement of a solvent for carrying out the reaction (solvent-free conditions), faster reaction, and considerably pure products. Due to these reasons, ball milling has been successfully used in polymerization reactions, , multicomponent organic syntheses, , including gaseous reagents and carbon materials, crystal preparation, , asymmetric organic syntheses, and some other miscellaneous applications − in medicinal and pharmaceutical chemistries. , …”