Tuning of thermal and dielectric properties for epoxy composites filled with electrospun alumina fibers and graphene nanoplatelets through hybridization

2015 ◽  
Vol 3 (27) ◽  
pp. 7195-7202 ◽  
Author(s):  
Jun-Wei Zha ◽  
Tian-Xing Zhu ◽  
Yun-Hui Wu ◽  
Si-Jiao Wang ◽  
Robert K. Y. Li ◽  
...  

Epoxy resin is widely used for electrical and electronics packaging in various forms due to its excellent adhesion, low cure shrinkage and good electrical insulation.

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1180 ◽  
Author(s):  
Ahmad Ahmad ◽  
Sidek Ab Aziz ◽  
Zulkifly Abbas ◽  
Suzan Obaiys ◽  
Ahmad Khamis ◽  
...  

The preparation of chemically reduced graphene oxide (rGO) and the optimization of epoxy resins’ properties using micro or nanofillers are now common practices. rGO nanoparticles (60 nm) based on an epoxy resin polymer were prepared at the concentrations of 0, 1, 2, 3, 4, and 5% weight percentage with fixed 6-mm thicknesses. The dielectric properties of the composites were measured by the reflection/transmission technique in connection with a vector network analyser (VNA) at a frequency range of 8–12 GHz. The microwave absorption and shielding effectiveness properties were calculated by using the reflection S11 and transmission S21 results. The microstructure and morphology of the polymer and the rGO/cured epoxy composites were studied by field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared (FT-IR) spectroscopy, and the X-ray Diffraction (X-RD) technique for characterizing crystalline materials. The dielectric and other properties of the rGO/cured epoxy composites were investigated based on the filler load and frequency. It was found that the applied frequency and the filler concentrations affected the dielectric properties of the rGO/cured epoxy composites. The results showed that the introduction of rGO particles to the composites increased their dielectric properties smoothly. The study of the dependence on frequency of both the dielectric constant ε′ and the dielectric loss ε″ showed a decrease in both quantities with increasing frequency, indicating a normal behaviour of the dielectrics. Cole–Cole plots were drawn with ε′ and ε″. A theoretical simulation in terms of the Cole–Cole dispersion law indicates that the Debye relaxation processes in the rGO/cured epoxy composites are improved due to the presence of the rGO filler. Moreover, with the addition of rGO as a filler into the Epoxy matrix, it now exhibits promise as a lightweight material for microwave absorption as well as an effective electromagnetic interference (EMI) shielding material.


Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4417
Author(s):  
Xue Li ◽  
Ling Weng ◽  
Hebing Wang ◽  
Xiaoming Wang

To promote the construction of the thermal network in the epoxy resin (EP), a certain proportion of silver nanowires (AgNWs) coupled with the hexagonal boron nitride (BN) nanoplates were chosen as fillers to improve the thermal conductivity of EP resin. Before preparing the composites, BN was treated by silane coupling agent 3-aminopropyltriethoxysilane (KH550), and AgNWs was coated by dopamine hydrochloride. The BN/AgNWs/EP composites were prepared after curing, and the thermal conductivity and dielectric properties of the composites was tested. Results showed that the AgNWs and BN were uniformly dispersed in epoxy resin. It synergistically built a thermal network and greatly increased the thermal conductivity of the composites, which increased 9% after adding AgNWs. Moreover, the electrical property test showed that the addition of AgNWs had little effect on the dielectric constant and dielectric loss of the composites, indicating a rather good electrical insulation of the composites.


2015 ◽  
Vol 815 ◽  
pp. 607-610
Author(s):  
Qing Hou ◽  
Run Hua Fan ◽  
Zi Dong Zhang ◽  
Ke Lan Yan ◽  
Chuan Bing Cheng ◽  
...  

In this paper, epoxy resin was used as matrix to prepare composite cryomilling at liquid nitrogen temperature in which the content of CNTs powder vary from 25 wt% to 40 wt%. The microstructure and dielectric properties of the composite were analyzed by SEM and RF impedance material analyzer. The result showed that permittivity of the composites turned negative after the CNTs reached certain content. The plasma oscillation of delocalized electrons in CNTs conductive networks causes negative permittivity phenomenon.


RSC Advances ◽  
2014 ◽  
Vol 4 (103) ◽  
pp. 59409-59417 ◽  
Author(s):  
Yi Wang ◽  
Jinhong Yu ◽  
Wen Dai ◽  
Dong Wang ◽  
Yingze Song ◽  
...  

1D–2D SiCNWs–GNPs hybrid nanofillers could make epoxy composites not only excellent thermal conductors but also aid them in retaining high electrical insulation.


Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2451
Author(s):  
Jianwen Zhang ◽  
Dongwei Wang ◽  
Lujia Wang ◽  
Wanwan Zuo ◽  
Lijun Zhou ◽  
...  

To study the effect of hyperbranched polyester with different kinds of terminal groups on the thermomechanical and dielectric properties of silica–epoxy resin composite, a molecular dynamics simulation method was utilized. Pure epoxy resin and four groups of silica–epoxy resin composites were established, where the silica surface was hydrogenated, grafted with silane coupling agents, and grafted with hyperbranched polyester with terminal carboxyl and terminal hydroxyl, respectively. Then the thermal conductivity, glass transition temperature, elastic modulus, dielectric constant, free volume fraction, mean square displacement, hydrogen bonds, and binding energy of the five models were calculated. The results showed that the hyperbranched polyester significantly improved the thermomechanical and dielectric properties of the silica–epoxy composites compared with other surface treatments, and the terminal groups had an obvious effect on the enhancement effect. Among them, epoxy composite modified by the hyperbranched polyester with terminal carboxy exhibited the best thermomechanical properties and lowest dielectric constant. Our analysis of the microstructure found that the two systems grafted with hyperbranched polyester had a smaller free volume fraction (FFV) and mean square displacement (MSD), and the larger number of hydrogen bonds and greater binding energy, indicating that weaker strength of molecular segments motion and stronger interfacial bonding between silica and epoxy resin matrix were the reasons for the enhancement of the thermomechanical and dielectric properties.


2021 ◽  
Vol 412 ◽  
pp. 128647
Author(s):  
Jingjing Meng ◽  
Pengfei Chen ◽  
Rui Yang ◽  
Linli Dai ◽  
Cheng Yao ◽  
...  

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