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1.
We report an in situ thermal reduction of graphene oxide (GO) in a styrene–ethylene/butylene–styrene (SEBS) triblock copolymer matrix during a melt‐blending process. A relatively high degree of reduction was achieved by melt‐blending premixed GO/SEBS nanocomposites in a Haake mixer for 25 min at 225 °C. Infrared spectral results revealed the successful thermal reduction of, and the strong adsorption of SEBS on, the graphene sheets. The glass transition temperature of polystyrene (PS) segments in SEBS was enhanced by the incorporation of thermally reduced graphene oxide (TRGO). The resultant TRGO/SEBS nanocomposites were used as a masterbatch to improve the mechanical properties of PS. Both the elongation at break and the flexural strength of PS/SEBS blends were enhanced with the addition of the TRGO. Our demonstration of the in situ thermal reduction of GO via melt blending is a simple, efficient strategy for preparing nanocomposites with well‐dispersed TRGO in the polymer matrix, which could be an important route for large‐scale fabrication of high‐performance graphene/polymer nanocomposites. © 2013 Society of Chemical Industry  相似文献   

2.
Nanocomposites based on poly(styrene‐b‐ethylene‐ran‐butylene‐b‐styrene) (SEBS) and carbon nanotubes (CNTs) (SEBS/CNT) as well as SEBS grafted with maleic anhydride (SEBS‐MA)/CNT were successfully prepared for electromagnetic shielding applications. Both SEBS/CNT and SEBS‐MA/CNT nanocomposites were prepared by melt compounding and were post‐processed using two different techniques: tape extrusion and compression moulding. The different nanocomposites were characterized by Raman spectroscopy and rheological analysis. Their mechanical properties, electrical properties (10-2–105 Hz) and electromagnetic shielding effectiveness (8.2–12.4 GHz) were also evaluated. The results showed that the CNT loading amount, the presence of MA in the matrix and the shaping technique used strongly influence the final morphologies and properties of the nanocomposites. Whilst the nanocomposite containing 8 wt% CNTs prepared by compression moulding presented the highest electromagnetic shielding effectiveness (with a value of 56.73 dB, which corresponds to an attenuation of 99.9996% of the incident radiation), the nanocomposite containing 5 wt% CNTs prepared by tape extrusion presented the best balance between electromagnetic and mechanical properties and was a good candidate to be used as an efficient flexible electromagnetic interference shielding material. © 2018 Society of Chemical Industry  相似文献   

3.
In this report, multiwalled carbon nanotubes (CNT) embedded poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) microspheres (CNT/SEBS) were prepared by solvent evaporation method. Reduced graphene oxide (rGO) nanosheets were used to cover the surface of CNT/SEBS microspheres. The CNT/SEBS/rGO nanocomposites with special segregated conductive network were fabricated by hot pressing these as-prepared complex microspheres. The morphology, electrical percolation threshold, electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness (SE) of CNT/SEBS/rGO composites were characterized. The shielding mechanisms were discussed in detail. Analysis of electrical conductive performance shows that the electrical percolation threshold of rGO is 0.22 vol %. Results of EMI shielding test confirmed the synergistic effect between CNT and rGO. The EMI SE of the composite filled by 2.1 vol % CNT and 3.35 vol % rGO can achieve 26 dB in 8.2− 12.4 GHz (X band), which exceeds the basic requirement for commercial application (20 dB). Its reflectance coefficient (19–41%) indicates that the most part of incident electromagnetic (EM) wave energy is attenuated through absorption mechanism. This kind of absorptive EMI shielding material can be applied without serious secondary EM radiation pollution problems. The effects of filler content, molding temperature on EMI SE, and shielding mechanism were also investigated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48542.  相似文献   

4.
Polymer nanocomposites were prepared by in situ polymerization of aniline with graphite oxide (GO), γ-Fe2O3, and BaTiO3 as electromagnetic interference (EMI) shielding materials. GO, γ-Fe2O3, and BaTiO3 nanoparticles were incorporated in the nanocomposites to improve the electromagnetic properties. The nanocomposites showed the significant improvement in both EMI shielding efficiency (SE) and thermal property due to the thermal conductivity of GO, the magnetic effect of γ-Fe2O3, and the electric effect of BaTiO3. The EMI SE of nanocomposites was improved due to the synergetic effect of reflection and absorption of electromagnetic interference by GO, γ-Fe2O3, and BaTiO3 additives.  相似文献   

5.
Graphene quantum dots (GQDs) reinforced poly(vinyl alcohol) (PVA)/polypyrrole (WPPy) nanocomposite films with various GQDs loadings were synthesized using the versatile solvent casting method. The structural and morphological properties of PVA/WPPy/GQDs nanocomposite films were investigated by employing Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The thermogravimetric analysis revealed enhanced thermal stability of synthesized nanocomposites while enhanced dielectric properties were also observed. The maximum dielectric constant value for PVA/WPPy/GQDs nanocomposite films was observed to be ε = 6,311.85 (50 Hz, 150°C). The electromagnetic interference (EMI) shielding effectiveness (SE) of nanocomposite films was determined in the X-band (8–12 GHz) and Ku-band (12–18 GHz) frequency region. The EMI SE was found to be increased from 0.8 dB for the pure PVA film to 9.8 dB for the PVA/WPPy/GQDs nanocomposite film containing 10 wt% GQDs loading. The enhanced EMI shielding efficiency of nanocomposite films has resulted from the homogenous dispersion of GQDs in PVA/WPPy blend nanocomposites. Thus, the prepared nanocomposites are envisioned to utilize as a lightweight, flexible, and low-cost material for EMI shielding applications.  相似文献   

6.
This article presents the effect of exfoliation, dispersion, and electrical conductivity of graphene sheets onto the electrical, electromagnetic interference (EMI) shielding, and gas barrier properties of thermoplastic polyurethane (TPU) based nanocomposite films. The chemically reduced graphene (CRG) and thermally reduced/annealed graphene (TRG) having Brunauer–Emmett–Teller surface areas of 18.2 and 159.6 m2/g, respectively, when solution blended with TPU matrix using N,N-dimethylformamide as a solvent. Graphene sheets based TPU nanocomposites have been evaluated and compared for EMI shielding in Ku band, electrical conductivity, and gas barrier property. TRG/TPU nanocomposite films showed excellent gas barrier against N2 gas as compared to CRG/TPU. The EMI shielding effectiveness for neat CRG and TRG graphene sheets is found to be −80, −45 dB, respectively, at 2 mm thickness. The EMI shielding data revealed that TRG/TPU nanocomposites showed better shielding at lower concentration (10 wt %), while CRG displayed better attenuation at higher concentrations. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47666.  相似文献   

7.
Ceramic matrix nanocomposites containing graphene possess superior mechanical properties. However, these nanocomposites are very difficult to be prepared using the conventional methods due to severe grain growth and simultaneous degradation of the graphene at high sintering temperatures and long dwell time. Herein, the dense ZrO2/rGO (reduced graphene oxide) nanocomposites are successfully fabricated by flash sintering of the green compacts consisting of ZrO2 nanoparticles and graphene oxide (GO) at 893–951℃ in merely 5 seconds under the alternating current (AC) electric fields of 130–150 V cm−1. The GO can be in situ thermal reduced during the flash sintering. The as-prepared ZrO2/rGO nanocomposites exhibit excellent mechanical properties. This study presents a green and simple approach to fabricate the dense ceramic matrix nanocomposites reinforced with graphene at low temperatures in a short time.  相似文献   

8.
This article aims to investigate the impact of reduced graphene oxide (RGO) nanofillers on the curing kinetics, thermal stability, mechanical modulus, electrical conductivity, and EMI shielding effectiveness of unsaturated polyester resin (UPR). The curing rates of UPR/styrene (60/40 by wt%) mixtures with small amounts of RGO (0.1–0.3 wt%) exhibit slight delays owing to the barrier and scavenger roles of 2-dimensional RGO sheets. Nonetheless, it is observed that within the cured nanocomposites, RGOs are effectively dispersed and firmly bonded to the UPR matrix at interfaces through hydrogen bonding and π-π interactions. Consequently, the nanocomposites display heightened thermal decomposition temperatures and increased residue at 800°C with higher RGO loading content. The addition of RGO notably improves the elastic storage modulus and increases the temperature associated with glass transition-related relaxation. The electrical percolation threshold is attained at a specific RGO loading between 0.2 and 0.3 wt%. Thus, the nanocomposite with 0.3 wt% RGO is characterized to have an electrical conductivity of 1.9 × 10−6 S/cm and an EMI shielding effectiveness of ~9 dB at 8 GHz, for a thickness of 1 mm.  相似文献   

9.
《Ceramics International》2022,48(2):1690-1698
Considering the promising efficiency of composites, in the current study, a graphene oxide (GO)-magnetite-Prussian blue (PB) composite material was prepared. The composite exhibited electrical conductivity, magnetic permeability, and permittivity nature, and was evaluated using electromagnetic interference (EMI) shielding studies. GO was developed by the Hummer's method, ferrite (Fe3O4) was incorporated by the sol-gel method, and PB was introduced in the mixture by an in-situ process. The fabricated samples were studied by X-ray diffraction, Raman Spectroscopy, Fourier-transform infrared spectroscopy along with EMI shielding efficiency (SE) evaluation. The SE of ?71.66 dB of reflection losses was measured at a frequency of 1.5 MHz. The GO/Fe3O4/PB composite provided the best results for the detection in the 1–18 MHz frequency range because of its excellent electric and magnetic properties. The obtained results demonstrated that the GO/Fe3O4/PB composite has promising potential applications in EMI shielding.  相似文献   

10.
In the present work, the nanocomposites based on different transition metal oxides like iron oxide (Fe2O3), zinc oxide (ZnO), silicon dioxide (SiO2), zirconium dioxide (ZrO2), and titanium dioxide (TiO2) in PVA matrix have been studied for their suitability as electromagnetic interference (EMI) shielding materials in the frequency range of 4–8 GHz (C-band) and 8–12 GHz (X-band). The nanocomposites containing 0.1, 0.5, 1.0, 5.0, and 10.0 wt% of oxides in the matrix were synthesised by solvent casting method. The EMI attenuation studies in 4–12 GHz frequency range were carried out using the Vector Network Analyzer R & S: ZVA40 method by measuring the loss due to reflection. The minimum reflectivity values for the composites containing Fe2O3, ZnO, SiO2, ZrO2, and TiO2 in PVA matrix at 10 wt% concentration level in the matrix were found to be ?38.85 dB (10.4 GHz), ?33.65 dB (10.4 GHz), ?41.90 dB (10.4 GHz), ?24.90 dB (11.0 GHz), and ?32.90 dB (9.76 GHz), respectively. Based on these results, the SiO2- and Fe2O3-based composites, which also exhibit high thermal stability and mechanical strength, are found to be low-cost and efficient EMI shielding materials.  相似文献   

11.
In this article is reported the preparation of carbon nanohorn (CNH)/graphene nanoplates (GNP)/polystyrene (PS) nanocomposites through in‐situ bulk polymerization of styrene monomer in the presence of CNH, followed by the addition of suspension polymerized GNP/PS bead during polymerization of styrene, as next‐generation multifunctional material for high electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) applications. Morphological analysis revealed selective dispersion of CNH in bulk polymerized PS matrix, where GNP/PS beads were randomly distributed. The formation of continuous CNH–CNH conductive path and GNP–CNH–GNP or CNH–GNP–CNH conductive network throughout the PS matrix at exceptionally low loading of CNH (1.0 wt %) and GNP (0.15 wt %) leads to high electrical conductivity (6.24 × 10?2 S cm?1) and EMI SE ~(?24.83 dB) when the nanocomposites was prepared in the presence of 75 wt % GNP/PS bead. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42803.  相似文献   

12.
《Ceramics International》2022,48(8):11031-11042
Polyaniline (PANI) and its composite with sulphur doped reduced graphene oxide (S-RGO) have been successively synthesized via in-situ chemical oxidative polymerization of aniline in presence of 10 wt. % S-RGO nanosheets. Physico-chemical analyses of the synthesized nanomaterial was performed with various characterization techniques such as X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Atomic Force Microscopy (AFM) and Thermogravimetric analysis/Differential Scanning Calorimetry (TGA/DSC). The results interpreted from the various characterizations confirm the doping of RGO with sulphur as well as strong interaction of PANI nanofibers and S-RGO nanosheets. TG/DSC curves confirm the enhanced thermal stability of polyaniline/sulphur doped reduced graphene oxide (PANI/S-RGO) nanocomposites with heat resistance index (THRI) of 155.2 °C in comparision to pure PANI (THRI = 145.3 °C) at a filler loading of 10 wt. %. TGA validates that thermal stability of PANI/S-RGO nanocomposite improves by 6–7 °C than pure PANI in terms of weight loss percentage at a temperature of 1117 °C. However DSC analysis confirms that PANI/S-RGO retains its structural integrity and conformity to temperatures as high as 900 °C beyond which the polymer composite starts to degrade. The electromagnetic interference shielding effectiveness (EMI SE) of PANI and PANI/S-RGO nanocomposites were measured via open-ended coaxial probe set-up connected to a Vector Network Analyser (VNA) at a broadband frequency range of 1–20 GHz (1000–20000 MHz). For EMI SE measurements the various nanomaterials were incorporated into paraffin wax and made into composite pellets of thickness 5 mm by solution casting technique. The dielectric properties, electrical conductivity and EMI SE were all greatly enhanced for the PANI/S-RGO/Paraffin composite pellets. The as synthesized PANI/S-RGO/Paraffin composite pellets exhibited highest EMI SE of ?22.5 dB (>99%) as compared to ?15.89 dB of PANI/Paraffin composite pellets. The prepared composite pellets revealed an absorption dominant mechanism of shielding with highest SEA of ?14.6 dB for PANI/S-RGO/Paraffin composite pellets.  相似文献   

13.
Poly(lactic acid)/organo‐montmorillonite (PLA/OMMT) nanocomposites toughened with maleated styrene‐ethylene/butylene‐styrene (SEBS‐g‐MAH) were prepared by melt‐compounding using co‐rotating twin‐screw extruder followed by injection molding. The dispersibility and intercalation/exfoliation of OMMT in PLA was characterized using X‐ray diffraction and transmission electron microscopy (TEM). The mechanical properties of the PLA nanocomposites was investigated by tensile and Izod impact tests. Thermogravimetric analyzer and differential scanning calorimeter were used to study the thermal behaviors of the nanocomposite. The homogenous dispersion of the OMMT silicate layers and SEBS‐g‐MAH encapsulated OMMT layered silicate can be observed from TEM. Impact strength and elongation at break of the PLA nanocomposites was enhanced significantly by the addition of SEBS‐g‐MAH. Thermal stability of the PLA/OMMT nanocomposites was improved in the presence of SEBS‐g‐MAH. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

14.
In the present work, Zeolite 13X and carbon black nanoparticles (CBNPs) reinforced polyvinylidene fluoride (PVDF) nanocomposites were obtained by a simple solvent casting technique. The structural, morphological and thermal properties of PVDF/Zeolite 13X/CBNPs nanocomposites with various loadings of Zeolite 13X and CBNPs were investigated using Fourier-transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy and thermo-gravimetric analysis. The dielectric studies were carried out in the 50 Hz–10 MHz frequency range at room temperature. The electromagnetic interference (EMI) shielding effectiveness (SE) of PVDF/Zeolite 13X/CBNPs nanocomposite was investigated in the 8–18 GHz frequency region (X-band and Ku-band). The maximum EMI SE of approximately −11.1 dB (8–12 GHz) and −11.5 dB (12–18 GHz) was observed for PVDF/CBNPs nanocomposites with 10 wt% loading of CBNPs. These findings emphasize the application of PVDF/Zeolite 13X/CBNPs nanocomposites as a potential EMI shielding material.  相似文献   

15.
To develop new tribomaterials for mechanical sliding parts, investigations were carried out on the influence of adding styrene–ethylene/butylene–styrene block copolymer (SEBS) on the rheological, mechanical, and tribological properties of polyamide 6 (PA6) nanocomposite, which is a commercial product of layered silicate (clay) filled polyamide 6 (PA6/Clay). Two kinds of block copolymers, unmodified SEBS (SEBS) and maleic anhydride‐grafted SEBS (SEBS‐g‐MA), were added with PA6/Clay nanocomposite. Dynamic viscoelastic properties in the molten state of these nanocomposites and their tensile, impact, and tribological properties of these nanocomposites were evaluated. Dynamic viscoelastic properties were found to increase with the addition of SEBS and were influenced, in particular, by block copolymers containing SEBS‐g‐MA. Influence of the addition of SEBS on mechanical properties of these systems differed for each mechanical property. Although tensile properties decreased with SEBS, Izod impact properties were improved with the addition of SEBS‐g‐MA. Tribological properties were improved with the addition of block copolymer, and the influence of the amount of addition was higher than the type of block copolymer used. These results indicate that new tribomaterials developed have sufficient balance amongst moldability, mechanical, and tribological properties. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers  相似文献   

16.
An effective synthesis strategy of hybrid metal (PtRu)/metal oxide (SnO2) nanoparticles on graphene nanocomposites is developed using a microwave-assisted one-pot reaction process. The mixture of ethylene glycol (EG) and water is used as both solvent and reactant. In the reaction system for the synthesis of SnO2/graphene nanocomposite, EG not only reduces graphene oxide (GO) to graphene, but also results in the formation of SnO2 facilitated by the presence of a small amount of water. On the other hand, in the reaction system for preparation of PtRu/graphene nanocomposites, EG acts as solvent and reducing agent for reduction of PtRu nanoparticles from their precursors and reduction of graphene from graphene oxide. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) characterizations confirm the feasibility of the microwave-assisted reaction system to simultaneously reduce graphene oxide and to form SnO2 or PtRu nanoparticles. The as-synthesized SnO2/graphene hybrid composites show a much higher supercapacitance than the pure graphene, and the as-prepared PtRu/graphene show much better electrocatalytic activity for methanol oxidation compared to the commercial E-TEK PtRu/C electrocatalysts.  相似文献   

17.
A novel nitrile butadiene rubber (NBR)/magnetite (Fe3O4) nanocomposite for electromagnetic interference (EMI) shielding at microwave frequency was successfully fabricated. The structural features of as-synthesized magnetite and NBR/Fe3O4 were examined by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The number of elastically effective chains, volume fraction of rubber, interparticle distance among conductive sites, polymer–filler interaction, and porosity of the nanocomposites were evaluated. The mechanical properties, including the tensile strength, elongation at break, and hardness, of the composites were measured. The static electrical properties, such as the electrical conductivity, carrier mobility, and number of charge carriers, as a function of magnetite content were evaluated. The interrelation between the electrical conductivity, shielding effectiveness (SE), dielectric constant, and skin depth of the composites are discussed. Finally, the EMI SE versus frequency was tested. The results reveal that an SE of 28–91 dB against EMI in the 1–12 GHz range depended on the loading of the conducting magnetite within the NBR matrix. Accordingly, these nanocomposites may used in the field of microwave absorption devices. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

18.
Electrical and electromagnetic interference shielding effectiveness (EMI SE) properties of the ethylene methyl acrylate (EMA)/multiwalled carbon nanotube (MWNT) nanocomposites have been studied. High resolution transmission electron microscope (HRTEM) was used to validate the MWNTs dispersion state and network connections of its microstructure. The electrical resistance of the nanocomposites decreases significantly with MWNTs content. DC resistivity and AC conductivity measurement on the nanocomposite samples showed that the insulator to conductor transition took place within 10 wt% MWNTs concentration. It has been found that as MWNT concentration increased network connections improved. The EMI SE of the nanocomposites has also been investigated. The highest SE (∼20 dB) of these nanocomposites is realistic for an industrial application. EMA/MWNT nanocomposites provide sufficient intrinsic EMI shielding capability which may be hopeful for electrical and electronic applications. The morphology correlates well with the electrical and electromagnetic behavior of these nanocomposites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers  相似文献   

19.
Synthesis and characterization of a novel toughener–compatibilizer for polypropylene (PP)–montmorillonite (MMT) nanocomposites were conducted to provide enhanced mechanical and thermal properties. Poly(ethylene oxide) (PEO) blocks were synthetically grafted onto maleic anhydride‐grafted polystyrene‐block‐poly(ethylene/butylene)‐block‐polystyrene (SEBS‐g‐MA). Special attention was paid to emphasize the effect of PEO‐grafted SEBS (SEBS‐g‐PEO) against SEBS‐g‐MA on morphology, static/dynamic mechanical properties and surface hydrophilicity of the resultant blends and nanocomposites. It was found that the silicate layers of neat MMT are well separated by PEO chains chemically bonded to nonpolar SEBS polymer without needing any organophilic modification of the clay as confirmed by X‐ray diffraction and transmission electron microscopy analyses. From scanning electron microscopy analyses, elastomeric domains interacting with MMT layers via PEO sites were found to be distributed in the PP matrix with higher number and smaller sizes than the corresponding blend. As a benefit of PEO grafting, SEBS‐g‐PEO‐containing nanocomposite exhibited not only higher toughness/impact strength but also increased creep recovery, as compared to corresponding SEBS‐g‐MA‐containing nanocomposite and neat PP. The damping parameter of the same nanocomposite was also found to be high in a broad range of temperatures as another advantage of the SEBS‐g‐PEO toughener–compatibilizer. The water contact angles of the blends and nanocomposites were found to be lower than that of neat hydrophobic PP which is desirable for finishing processes such as dyeing and coating. © 2018 Society of Chemical Industry  相似文献   

20.
In this study, poly(ethylene terephthalate)/organo‐montmorillonite (PET/OMMT) nanocomposites were melt‐compounded using twin screw extruder followed by injection molding. Maleic anhydride grafted styrene‐ethylene/butylene‐styrene (SEBS‐g‐MAH) was used to improve the impact properties of the PET/OMMT nanocomposites. The notched and un‐notched impact strength of PET/OMMT nanocomposites increased at about 2.5 times and 5.5 times by the addition of 5 wt % of SEBS‐g‐MAH. Atomic force microscopy (AFM) scans were taken from the polished surface of both PET/OMMT and SEBS‐g‐MAH toughened PET/OMMT nanocomposites. The addition of SEBS‐g‐MAH altered the phase structure and clay dispersion in PET matrix. It was found that some of the OMMT silicate layers were encapsulated by SEBS‐g‐MAH. Further, the addition of SEBS‐g‐MAH decreased the degree of crystallinity of the PET/OMMT nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

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