Alignment of Dispersed Single-walled Carbon Nanotubes in Viscous Polymer Flow
نویسندگان
چکیده
This research describes the effects of shear flow-induced alignment of dispersed single-walled carbon nanotubes in viscous polymer solutions and the application of this alignment strategy to produce epoxy-based composites with superior mechanical properties. Previously, it was shown that the use of an anionic surfactant (i.e. sodium dodecylbenzene sulfonate, NaDDBS) in conjunction with a weakly binding polymer (i.e. carboxy methyl cellulose, CMC) were necessary to disperse the single-walled carbon nanotubes, and subsequently, align them in shear flow. The current work builds on these results and extends the utilization of the dispersing agents to include not only an anionic surfactant, but also a polymeric surfactant such as a Pluronic-a PEO/PPO multiblock copolymer. The epoxy matrix was incorporated into the dispersed SWNT suspension during the alignment process. It is important to note that dispersing agent concentration and identity are not the only factors to consider when aligning carbon nanotubes in shear flow as a polymer sets. It is inconclusive whether the SWNT in resulting shear flow-aligned epoxy composites were aligned. However, these composites exhibited significantly increased moduli compared to that of a pure epoxy matrix. It appears that the incorporation of dispersed SWNT into an epoxy matrix may have inhibited the alignment of the carbon nanotubes when subjected to shear forces. However, regions of localized aligned carbon nanotubes parallel and perpendicular to the shear forces may have possibly been created. The significant increase of the elastic and shear moduli of the epoxy-based matrix are discussed in light of these phenomena.
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