title: Isolation of Aramid Nanofibers for High Strength and Toughness Polymer Nanocomposites.
abstract: The development of nanoscale reinforcements that can be used to improve the mechanical properties of a polymer remains a challenge due to the long-standing difficulties with exfoliation and dispersion of existing materials. The dissimilar chemical nature of common nanofillers (e.g., carbon nanotubes, graphene) and polymeric matrix materials is the main reason for imperfect filler dispersion and, consequently, low mechanical performance of their composites relative to theoretical predictions. Here, aramid nanofibers that are intrinsically dispersible in many polymers are prepared from commercial aramid fibers (Kevlar) and isolated through a simple, scalable, and low-cost controlled dissolution method. Integration of the aramid nanofibers in an epoxy resin results in nanocomposites with simultaneously improved elastic modulus, strength, and fracture toughness. The improvement of these two mutually exclusive properties of nanocomposites is comparable to the enhancement of widely reported carbon nanotube reinforced nanocomposites but with a cost-effective and more feasible method to achieve uniform and stable dispersion. The results indicate the potential for aramid nanofibers as a new class of reinforcements for polymers.
authors.affiliation: Department of Macromolecular Science and Engineering, ‡Department of Aerospace Engineering, and §Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
authors.forename: Jiajun
authors.identifier: http://orcid.org/0000-0001-7086-7150
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Macromolecular Science and Engineering, ‡Department of Aerospace Engineering, and §Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
authors.forename: Sun Hwi
authors.initials: SH
authors.lastname: Bang
authors.affiliation: Department of Macromolecular Science and Engineering, ‡Department of Aerospace Engineering, and §Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
authors.forename: Mohammad H
authors.initials: MH
authors.lastname: Malakooti
authors.affiliation: Department of Macromolecular Science and Engineering, ‡Department of Aerospace Engineering, and §Department of Materials Science and Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
authors.forename: Henry A
authors.initials: HA
authors.lastname: Sodano
keywords: aramid nanofibers; elastic modulus; fractography; fracture toughness; nanocomposites