Elongational flow mixing for manufacturing of graphite nanoplatelet/polystyrene composites

Abstract

Manufacturing strategy is of prime importance for the appropriate incorporation of filler into a polymeric matrix, and this in particular refers to nanofillers. Herein, direct-graphite nanoplatelets are used as filler in polystyrene. The as-received filler material contained microscopic size agglomerates formed by nanoscopic size graphite nanoplatelets. Refining of the microagglomerates (break-up) and production of, desirably, single graphene layers (exfoliation) is the ultimate target for controlling production and thus properties of the present materials. Several processing methods including microcompounding, roll-milling/calendering, Brabender mixing chamber, and solvent processing are used and compared with elongational flow mixing by a newly developed mixer. For the present system, sonication with surfactant assistance solvent processing yields both good micro deagglomeration and production of thin graphene nanostacks/layers. Also the elongational flow mixing efficiently refines the microagglomerates. Solvent processing and microcompounding are more efficient than the other processes in the production of exfoliated thin graphene stacks/layers.

Effect of carbon black on electrical and rheological properties of graphite nanoplatelets/poly(ethylene-butyl acrylate) composites

“…The same pattern can be seen for the hybrid formulations where for example the solution-mixed 80-20 hybrid at 10 wt% (4.7 vol%) had similar conductivity level as the 7.7 vol% melt mixed composition. Based on these results, the solution-mixing process was more efficient in terms of filler dispersion in comparison with the melt-mixing one for this specific combination of polymer and filler, something that has been seen in earlier works of many authors [26,[28][29][30]. In the work by Oxfall et al, [28] GNP was mixed with polystyrene (PS), and it was observed that relatively large agglomerates were present in the composite after the melt mixing process.…”

“…Based on these results, the solution-mixing process was more efficient in terms of filler dispersion in comparison with the melt-mixing one for this specific combination of polymer and filler, something that has been seen in earlier works of many authors [26,[28][29][30]. In the work by Oxfall et al, [28] GNP was mixed with polystyrene (PS), and it was observed that relatively large agglomerates were present in the composite after the melt mixing process. However when a solutionmixing method was employed, the number of large agglomerates was dramatically reduced resulting in a higher conductivity.…”

“…In the present study, no differences could be discerned between the solvent and melt mixed systems with respect to the overall agglomerate size, se Figure 8. The decrease in percolation threshold observed when the solution-mixing method is used is thought to originate from the more efficient formation of thin graphite stacks [28].…”

Effects of Graphene Nanoplatelets and Reduced Graphene Oxide on Poly(lactic acid) and Plasticized Poly(lactic acid): A Comparative Study

“…In principle, it would be expected that the incorporation of rGO would lead to a stronger reinforcement effect than the incorporation of Graphene Nanoplatelets (xGnP), considering that the rGO exist in an exfoliated individual graphene sheets which had an even higher aspect ratio than xGnP. There are many studies on graphene composites based on a range of polymers available in literature, e.g., polycarbonate [16], Nylon [17], poly(methyl methacrylate) [18], poly(vinylidene fluoride), epoxy [19], poly(vinyl alcohol) [20], polystyrene [21], poly(ethylene disulfide) [22], poly(propylene) [23], poly(lactic acid) [24,25], etc. An investigation on the mechanical aspects of epoxy/xGnP by Chanrasekaran et al [19] showed that effective mechanical reinforcement was achieved for 0.5 wt% with 17% increase in glassy storage modulus.…”

Melt spinning of conductive textile fibers with hybridized graphite nanoplatelets and carbon black filler

“…In order to achieve a homogenous dispersion of graphene in polymers, more or less elaborate methods to disperse graphene in polymers have been applied . Among the different manufacturing methods, it was shown that solvent processing, elongational flow mixing and microcompounding are efficient in the dispersion and production of thin stacks of graphene in a polymer matrix . However, from an industrial and environmental point of view direct melt compounding is a preferred route.…”