High yield production and purification of few layer graphene by Gum Arabic assisted physical sonication

Abstract

Exploiting the emulsification properties of low cost, environmentally safe Gum Arabic we demonstrate a high yield process to produce a few layer graphene with a low defect ratio, maintaining the pristine graphite structure. In addition, we demonstrate the need for and efficacy of an acid hydrolysis treatment to remove the polymer residues to produce 100% pure graphene. The scalable process gives yield of up to 5 wt% graphene based on 10 g starting graphite. The graphene product is compared with reduced graphene oxide produced through Hummer's method using UV-visible spectroscopy, SEM, TEM, and Raman spectroscopy. The two graphene materials show significant difference in these characterizations. Further, the film fabricated from this graphene exhibits 20 times higher electrical conductivity than that of the reduced graphene oxide. Sonication processing of graphite with environmentally approved biopolymers such as Gum Arabic opens up a scalable avenue for production of cheap graphene.

Application of graphene from exfoliation in kitchen mixer allows mechanical reinforcement of PVA/graphene film

“…Figure 1 shows the transparency level of deposited G GA against grid background, which could be used to confirm the thin layer nature of graphene. The wrinkleless sheets here indicate the absence of defect on the graphene surface after functionalisation with gum Arabic (Chabot et al 2013;Fan et al 2012). Sharp edges of graphene sheets meanwhile were caused by fragmentation mechanism during the exfoliation stage .…”

“…While reduction of graphene oxide to graphene was responsible for the dissociation of H-bonds in the structure, the increase of H-bonds in our PVA may be caused by the direct dispersion of G GA in the matrix. The presence of oxygen groups on G GA (Chabot et al 2013;Fan et al 2012) has led to the increase of more oxygen content in PVA. The evidences for a complete dispersion of graphene in PVA are provided by the shift of IR band at 3460 cm -1 and elimination of IR peak at 1638 cm -1 in the spectra of PVA/-graphene films.…”

Graphene/Na carboxymethyl cellulose composite for Li-ion batteries prepared by enhanced liquid exfoliation

“…polyvinylpyrrolidone [30], poly(vinyl acetate) [31], poly(methyl methacrylate) [31], Gum Arabic [32], ethylcellulose [33], sodium carboxymethylcellulose (NaCMC) [30]). However, similar to surfactants, the final graphene product is expected to be contaminated with polymer.…”

“…If graphene containing ethylcellulose solution was dried, the final graphene content in polymer composite would be less than 1.2 wt% which is extremely low taking into account that the binder content in electrode formulations usually does not exceed 5-10 wt% and amount of active material should be maximized (∼90 wt%). Another drawback of sonication assisted liquid exfoliation of graphite is time consuming: hundreds of hours of sonication are required to get reasonable graphene concentration [21,22,32] which impedes using this method for scalable graphene composite production.…”

Effects of surfactants on the properties of epoxy/graphene nanocomposites

“…For GA, by exfoliating graphite in GA aqueous solution, high yielding and stable dispersion of graphene had been achieved. [35][36][37] GA has also been reported to disperse graphene and produce hydrogel, 38 polyethylene oxide 39 nanocomposites, etc.…”