In the last decade, graphene has emerged as one of the best-performing reinforcement materials for nanocomposites. Incorporation of graphene into polymer results in a nanocomposite with a new microstructure responsible for its enhanced features. A morphological state of graphene flakes is one of the factors that govern formation of microstructure. Studies showed that graphene-oxide (GO) flakes can be found either as fully exfoliated or intercalated in polymerbased nanocomposites. While traditional parameters are commonly taken into consideration in theoretical assessment of properties of composites by means of micromechanical models, the morphological state is often ignored. This research aims to investigate the effect of morphological state of GO flakes on stiffness of nanocomposites with widely used micromechanical models, e.g., rule of mixtures, Hui-Shia and Halpin-Tsai. Pure sodium alginate and nanocomposites on its basis reinforced with 1.0 and 2.5 wt% GO were used in the study. Parameters required for modelling were quantified with microstructural characterisation. Micromechanical models were adapted to account for the morphological state of intercalation observed in the characterisation study. Tensile experiments were employed to assess the adopted models, and the effect matrix stiffness, GO thickness, spacing of intercalates as well as the Poisson's ratio and stiffness of inter-flake polymer layers was studied.
Different aspects of graphene-based materials (GBMs) and GBM-nanocomposites have been investigated due to their intriguing features; one of these features is their transparency. Transparency of GBMs has been of an interest to scientists and engineers mainly with regard to electronic devices. In this study, optical transmittance of structural, purpose-made nanocomposites reinforced with GBMs was analyzed to lay a foundation for optical microstructural characterization of nanocomposites in future studies. Two main types of GBM reinforcements were studied, graphene oxide (GO) and graphite nanoplates (GNPs). The nanocomposites investigated are GO/poly(vinyl alcohol), GO/sodium alginate, and GNP/epoxy with different volume fractions of GBMs. Together with UV-visible spectrophotometry, image-processing-assisted micro and macro photography were used to assess the transparency of GBMs embedded in the matrices. The micro and macro photography methods developed were proven to be an alternative way of measuring light transmittance of semi-transparent materials. It was found that there existed a linear relationship between light absorbance and a volume fraction of GBMs embedded in the same type of polymer matrices, provided that the nanocomposites of interest had the same thicknesses. This suggests that the GBM dispersion characteristics in the same type of polymer are similar and any possible change in crystal structure of polymer due to different volumetric contents of GBM does not have an effect on light transmittance of the matrices. The study also showed that the same types of GBMs could display different optical properties in different matrix materials. The results of this study will help to develop practical microstructural characterization techniques for GBM-based nanocomposites.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.