Structural and Dipole-Relaxation Processes in Epoxy-Multilayer Graphene Composites with Low Filler Content
| Autor: | Oleksandr V. Mischanchuk, Nadia Sigareva, Sergey V. Shul'ga, Borys Gorelov, A. M. Gorb, O. I. Polovina, Volodymyr O. Yukhymchuk |
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| Rok vydání: | 2021 |
| Předmět: |
dielectric permittivity
Materials science Polymers and Plastics Scanning electron microscope MathematicsofComputing_GENERAL Organic chemistry Article epoxy law.invention symbols.namesake polymer nanocomposites QD241-441 law Thermal stability Graphite Composite material Spectroscopy graphene multilayered Nanocomposite Graphene positron annihilation General Chemistry thermal destruction Dielectric spectroscopy TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES symbols Raman spectroscopy |
| Zdroj: | Polymers Polymers, Vol 13, Iss 3360, p 3360 (2021) Volume 13 Issue 19 |
| ISSN: | 2073-4360 |
| Popis: | Multilayered graphene nanoplatelets (MLGs) were prepared from thermally expanded graphite flakes using an electrochemical technique. Morphological characterization of MLGs was performed using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Raman spectroscopy (RS), and the Brunauer–Emmett–Teller (BET) method. DGEBA-epoxy-based nanocomposites filled with synthesized MLGs were studied using Static Mechanical Loading (SML), Thermal Desorption Mass Spectroscopy (TDMS), Broad-Band Dielectric Spectroscopy (BDS), and Positron Annihilation Lifetime Spectroscopy (PALS). The mass loading of the MLGs in the nanocomposites was varied between 0.0, 0.1, 0.2, 0.5, and 1% in the case of the SML study and 0.0, 1.0, 2, and 5% for the other measurements. Enhancements in the compression strength and the Young’s modulus were obtained at extremely low loadings (C≤ 0.01%). An essential increase in thermal stability and a decrease in destruction activation energy were observed at C≤ 5%. Both the dielectric permittivity (ε1) and the dielectric loss factor (ε2) increased with increasing C over the entire frequency region tested (4 Hz–8 MHz). Increased ε2 is correlated with decreased free volume when increasing C. Physical mechanisms of MLG–epoxy interactions underlying the effects observed are discussed. |
| Databáze: | OpenAIRE |
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