Next Article in Journal
On the Microstructure and Isothermal Oxidation at 800, 1200, and 1300 °C of the Al-25.5Nb-6Cr-0.5Hf (at %) Alloy
Previous Article in Journal
Modeling of the Influence of Chemical Composition, Sintering Temperature, Density, and Thickness in the Light Transmittance of Four Zirconia Dental Prostheses
Article Menu

Export Article

Open AccessArticle

A Study on Exfoliation of Expanded Graphite Stacks in Candelilla Wax

1
Department of Mathematics and Physics “Ennio De Giorgi”, University of Salento, Via per Arnesano, 73100 Lecce, Italy
2
Department of Advanced Materials, Research Center for Applied Chemistry (CIQA), Blvd. Enrique Reyna 140, Saltillo 25294, Mexico
3
Applied Physics Department, CINVESTAV-IPN, Apdo. Postal 73, Mérida 97310, Yucatán, Mexico
4
Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy
*
Authors to whom correspondence should be addressed.
Materials 2019, 12(16), 2530; https://doi.org/10.3390/ma12162530
Received: 27 June 2019 / Revised: 30 July 2019 / Accepted: 1 August 2019 / Published: 8 August 2019
(This article belongs to the Special Issue Mechanical and Rheological Behaviour of Polymer-Based Systems)
  |  
PDF [6662 KB, uploaded 16 August 2019]
  |  

Abstract

A novel, green route for pre-exfoliation of graphite based on a biodegradable polymer and high-power ultrasound is presented. Candelilla wax (CW), derived from the leaves of the candelilla plant, has been used for the first time as a natural non aqueous medium to induce the pre-exfoliation of expanded graphite (EG) under ultrasonic irradiation in an economical way. The proposed method uses also D-limonene as a natural organic solvent for reducing viscosity and increasing the affinity between the polar groups of EG and candelilla wax, thus improving the intercalation/exfoliation of EG. The quality of dispersion of the nanofiller in the natural wax matrix has been evaluated using multiple techniques. The addition of EG to wax and use of ultrasonic treatment leads to a reduced crystallinity, probably due to restrictions of the molecular movements, improved thermal stability of wax, and to an increased shear thinning exponent, which are all indicative of a high degree of EG dispersion. The ultrasonic dynamic mechanical results suggest a reduction in the cluster size and a better filler dispersion in the wax matrix promoted by polar or chemical reactions between the CW fractions and the graphite stacks, which was observed by XPS analysis. The results were compared to those obtained with paraffin, a synthetic wax, and confirmed the dispersion improvement obtained by using natural wax as a pre-exfoliating medium. View Full-Text
Keywords: candelilla wax; paraffin wax; graphite; exfoliation; rheology; dynamic mechanical analysis; sound velocity; attenuation; crystallization; nanocomposite candelilla wax; paraffin wax; graphite; exfoliation; rheology; dynamic mechanical analysis; sound velocity; attenuation; crystallization; nanocomposite
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Lionetto, F.; López-Muñoz, R.; Espinoza-González, C.; Mis-Fernández, R.; Rodríguez-Fernández, O.; Maffezzoli, A. A Study on Exfoliation of Expanded Graphite Stacks in Candelilla Wax. Materials 2019, 12, 2530.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top