The extensive development of electronic systems and telecommunications has lead to major concerns regarding electromagnetic pollution. Motivated by environmental questions and by a wide variety of applications, the quest for materials with high efficiency to mitigate electromagnetic interferences (EMI) pollution has become a mainstream field of research. This paper reviews the state-of-the-art research in the design and characterization of polymer/carbon based composites as EMI shielding materials. After a brief introduction, in Section 1, the electromagnetic theory will be briefly discussed in Section 2 setting the foundations of the strategies to be employed to design efficient EMI shielding materials. These materials will be classified in the next section by the type of carbon fillers, involving carbon black, carbon fiber, carbon nanotubes and graphene. The importance of the dispersion method into the polymer matrix (melt-blending, solution processing, etc.) on the final material properties will be discussed. The combination of carbon fillers with other constituents such as metallic nanoparticles or conductive polymers will be the topic of Section 4. The final section will address advanced complex architectures that are currently studied to improve the performances of EMI materials and, in some cases, to impart additional properties such as thermal management and mechanical resistance. In all these studies, we will discuss the efficiency of the composites/devices to absorb and/or reflect the EMI radiation.

Polymer/carbon based composites as electromagnetic interference (EMI) shielding materials

Rational design of core-shell Co@C microspheres for high-performance microwave absorption

One of the main issues in the production of polymer nanocomposites is the dispersion state of filler as multilayered graphene (MLG) and carbon nanotubes (CNTs) tend to agglomerate due to van der Waals forces. The agglomeration can be avoided by using organic solvents, selecting suitable dispersion and production methods, and functionalizing the fillers. Another proposed method is the use of hybrid fillers as synergistic effects can cause an improvement in the dispersion state of the fillers. In this review article, various aspects of each process that can help avoid filler agglomeration and improve dispersion state are discussed in detail. This review article would be helpful for both current and prospective researchers in the field of MLG- and CNT-based polymer nanocomposites to achieve maximum enhancement in mechanical, thermal, and electrical properties of produced polymer nanocomposites.

https://northumbria-test.eprints-hosting.org/id/document/263154

Reasons and remedies for the agglomeration of multilayered graphene and carbon nanotubes in polymers

Polylactic acid (PLA)/halloysite nanotube (HNT) composite mats were successfully fabricated via electrospinning. Composite mats reinforced by both unmodified and modified HNTs with a dispersant BYK-9076 were prepared at the HNT contents of 0, 1, 5 and 10 wt%/v. The influence of HNT content and modification was investigated comprehensively, based on several characterisation techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, mechanical testing, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). Typical modified Halpin–Tsai model and modified Halpin–Tsai laminate hybrid model in conventional composite theory were used, which were found difficult to predict the entire experimental data of elastic moduli for PLA/HNT composite mats, possibly arising from the nanosized effect of HNTs and some electrospun PLA nanofibres within composite mats.

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Polylactic acid (PLA)/halloysite nanotube (HNT) composite mats: Influence of HNT content and modification

One type of electroactive shape memory nanocomposite was fabricated, including cross-linked poly(e-caprolactone) (cPCL) and conductive multiwalled carbon nanotubes (MWNTs). The cross-linking reaction of the pristine poly(e-caprolactone) (PCL) was realized by using benzoyl peroxide (BPO) as an initiator. The raw MWNTs (Raw-M) were prefunctionalized by acid-oxidation process and covalent grafting with poly (ethylene glycol) (PEG), respectively. Three kinds of nanocomposites containing cPCL/Raw-M, cPCL/acid-oxidation MWNTs (AO-M) and cPCL/PEG grafted MWNTs (PEG-M) were obtained, and the mechanical, electrical and shape memory properties were further investigated. The influence of in vitro degradation on their shape memory and mechanical properties was also evaluated. The methyl thiazolyl tetrazolium (MTT) assay was performed to estimate their biocompatibility. The results displayed that these nanocomposites could perform favorable shape memory recovery both in hot water at 55 °C and in electric field with 50...

Electro-active Shape Memory Properties of Poly(ε-caprolactone)/Functionalized Multiwalled Carbon Nanotube Nanocomposite

Compression Responses of Preform in Vacuum Infusion Process

Electroless plating was utilized to deposit Cobalt (Co) on the surface of multi-walled carbon nanotubes (MWCNTs), and the technological parameters of electroless plating were optimized. To obtain optimized processing parameters, field-emission scanning electron microscope (FESEM) as well as energy dispersive spectroscopy (EDS) results were presented to show the morphology, components of as-prepared Co-MWCNTs. Based on the optimized processing parameters, Co-MWCNTs were prepared and filled into the epoxy resin to fabricate Co-MWCNTs composites. The electromagnetic properties of pure MWCNTs composites and Co-MWCNTs composites were studied. To sum up, the pure MWCNTs composites with a filler concentration of 2 wt% had an intense absorbing peak at 15.20 GHz, where the highest reflection loss ( R ) reached −21.41 dB. Compared to the pure MWCNTs composite at the same concentration, the Co-MWCNTs composites showed a higher impedance which implies a better potential absorbing property and makes Co-MWCNTs probable to be utilized in electromagnetic absorbing field.

A study of the electromagnetic properties of Cobalt-multiwalled carbon nanotubes (Co-MWCNTs) composites

The dispersion of SWCNTs treated by dispersing agents in glass fiber reinforced polymer composites

Studies of Electromagnetic Properties of MWCNTs after Electroless Plating with Co-Fe Alloy

It is an obstacle issue for carbon nanotubes (CNTs) particularly for single-wall carbon nanotubes (SWCNTs) with nano-level dispersion in fiber reinforced polymer matrix composites. In this paper, the dispersing agents such as Volan and BYK-9076 were employed to treat SWCNTs to improve their dispersion in the glass fiber/epoxy (GF/EP) composites. The dispersing results of SWCNTs in composites were observed by scanning electron microscopy (SEM). Then the glass transition temperature (T g ) of these kinds of composites with treated and untreated SWCNTs were obtained by dynamic mechanical thermal analysis (DMTA). Moreover, the flexural tests were performed on these composites. Based on the experiment results, the dispersion of SWCNTs was improved and the flexural property of SWCNTs/GF/EP composite was enhanced too.

Zhao Yan

Papers

Compression Responses of Preform in Vacuum Infusion Process

A study of the electromagnetic properties of Cobalt-multiwalled carbon nanotubes (Co-MWCNTs) composites

The dispersion of SWCNTs treated by dispersing agents in glass fiber reinforced polymer composites

Studies of Electromagnetic Properties of MWCNTs after Electroless Plating with Co-Fe Alloy

The dispersion of SWCNTs treated by dispersing agents in glass fiber reinforced polymer composites