Abstract
The coating of natural fiber by graphene oxide (GO) has, over, this past decade, attracted increasing attention as an effective way to improve the adhesion to polymer matrices and enhance the composite properties. In particular, the GO-functionalized 30 vol% curaua fiber (Ananas Erectifolius) reinforcing epoxy composite was found to display superior tensile and thermogravimetric properties as well as higher fiber/matrix interfacial shear strength. In this brief report, dynamic mechanical analysis (DMA) was conducted in up to 50 vol% GO-functionalized curaua fiber reinforced epoxy matrix (EM) composites. The objective was not only to extend the amount incorporated but also for the first time investigate the composite viscoelastic behavior. The GO functionalization of curaua fibers (GOCF) improved the DMA storage (E′) and loss (E″) modulus compared to the non-functionalized fiber composites. Values at 30 °C of both E′ (13.44 GPa) and E″ (0.67 GPa) for 50 vol% GO-functionalized curaua fiber reinforced epoxy matrix composites (50GOCF/EM) were substantially higher than those of 20 GOCF/EM with E′ (7.08 GPa) and E″ (0.22 GPa) as well as non-functionalized 50CF/EM with E′ (11.04 GPa) and E″ (0.45 GPa). All these results are above the neat epoxy previously reported values of E′ (3.86 GPa) and E″ (0.09 GPa). As for the tangent delta, the parameters associated with damping factor and glass transition temperature were not found to be significantly changed by GO functionalization, but decreased with respect to the neat epoxy due to chain mobility restriction.
Highlights
Introduction iationsThe past decade has witnessed an exponential growth in research works on the expected next-generation classes of natural fiber polymer composites (NFPC) with special characteristics for functional and advanced applications
1b was cleaned in running water and dried on a stove at functionalized curaua fiber (CF) in epoxy matrix (EM)
Variation of E0towith temperature for the investigated functionalization. Such needs be further investigated for a possiblecomposites threshold including that of neat epoxy from a previous work
Summary
The past decade has witnessed an exponential growth in research works on the expected next-generation classes of natural fiber polymer composites (NFPC) with special characteristics for functional and advanced applications. A second class of nanocomposites display significant advantages when compared to conventional composites [3,4]. Incorporation of graphene and graphene-based materials, either separately as in both fiber and matrix, constitutes another successful class of NFPC with enhanced properties [5]. Plain graphene with a different number of layers as in monolayer pristine graphene (PG), few-layers graphene (FLG), and multilayer graphene (MGL) as well as graphene-based materials such as exfoliated nanoplatelet (GNP), flakes (GF), nanoparticles (NG), carbon nanotubes (CNT), oxide (GO), and reduced graphene oxide (rGO) are contributing to substantially.
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