Combined effect of graphene oxide and MWCNTs on microwave absorbing performance of epoxy composites

Abstract

Currently, carbon nanotube (CNT) -based composites have been considered as microwave absorbers because of the fascinating properties of CNTs. In this work, multi-walled CNTs (MWCNTs) and graphene oxide (GO) -based epoxy composites (i.e. MWCNT/EPr and GO-MWCNT/EPr), with sample thickness of 2 mm, were prepared to study microwave absorbing properties in the frequency band of 8-18 GHz. Uniform dispersion of MWCNTs in the organic solvent and polymer matrix was achieved by preparation of GO. The test for electromagnetic parameters, i.e. complex permittivity and the permeability of the samples, was carried out with vector network analyzer (VNA) using reflectiontransmission waveguides. Results showed that GO-MWCNT/EPr composites have better absorption capability than MWCNT/EPr composites. The improved reflection loss for the composites with 0.4 wt% and 0.6 wt% of GO (out of total filler loading 6 wt%) were À14.32 dB and À14.29 dB, respectively. The improvement in reflection loss and absorption bandwidth for GO-MWCNTs composites suggested that MA features are synergistically effected by GO and MWCNTs. Further skin depth and shielding effectiveness terms are studied to observe overall mechanism of electromagnetic (EM) shielding which showed that multiple reflections also play a role in EM shielding.

Mechanically robust conductive carbon clusters confined ethylene methyl acrylate–based flexible composites for superior shielding effectiveness

“…Since a long period of time, metals have been used as EMI shielding materials but upcoming trend shifts towards polymer nanocomposites because of their light weight, noncorrosive nature and low price . Polymer nanocomposites fabricated with carbonaceous materials such as graphite, single and multiwall carbon nanotube (CNT), carbon fiber, and carbon black have been widely used as EMI shielding materials . Although use of expandable graphite, carbon nanofibers, and graphene nanoplatelets have been extensively used to reduce electrical percolation via the formation of conductive network through polymer matrices and offer necessary EMI shielding for commercialization, but they have limitations in processing, poor dispersion, and high production cost .…”

Graphene oxide/multi‐walled carbon nanotubes nanocompsite polyamide nanofiltration membrane for dyeing‐printing wastewater treatment

“…Multiwalled carbon nanotubes (MWCNTs) are nanomaterials with a multi‐layer tubular carbon structure and are well‐known for their unique pore structure, large specific surface area, and excellent thermal and mechanical properties 18 . MWCNTs are often used in the modification of polymer separation membranes 19 .…”

Desarrollo, caracterización y estudio de nuevos polímeros reforzados por dispersión de nanofases y nanofluidos

“…Investigaciones recientes [264,265], han revelado que las láminas de GO pueden adsorber nanotubos de carbono de pared múltiple a través de interacciones π-π y conseguir dispersiones estables en agua y en disolventes polares. Además, estos nanotubos de carbono actúan como puentes entre las láminas del GO, de manera que la nanoestructura híbrida presenta un efecto sinérgico notable entre las nanofases, que conlleva a una mayor capacitancia, en comparación con las nanofases por separado [266].…”

“…La unión no covalente del óxido de grafeno con el LI se puede realizar a través de interacciones van der Waals, por la interacción catión-π (entre el catión imidazolio del LI y la red sp 2 de óxido de grafeno) o por apilamiento π-π [531,532]. Mientras que como se recogía en la introducción, las interacciones π-π del óxido de grafeno con los nanotubos de carbono o la formación de puentes de nanotubos entre las láminas de óxido de grafeno han sido descritas para la formación de nanofases híbridas [264][265][266].…”

“…En las micrografías que se muestran en la Figura 4.2, correspondientes a la nanofase híbrida GO-NT, se observan las láminas de GO y los nanotubos de carbono de pared múltiple. Investigaciones recientes [264,265] han demostrado que las láminas de GO pueden adsorber nanotubos de carbono de pared múltiple a través de interacciones π-π y que estos nanotubos largos y tortuosos unen las láminas del GO e inhiben su agregación [267,269].…”