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1.
Multi‐walled carbon nanotube was modified with polymethyl methacrylate (MWCNT‐PMMA) by in situ solution radical polymerization in the presence of 2,2′‐Azobis (isobutyronitrile) as an initiator. The products with different addition of methyl methacrylate (MMA) were pressed into slices to prepare specimens for electrical conductivity testing. It was found that the MWCNT‐PMMA nanocomposites demonstrate excellent electrical conductivity. To investigate the microsphere morphology and the colloidal surfactant of MWCNTs in MWCNT‐PMMA composites, samples were submitted to scanning electron microscopy and transmission electron microscopy. The thermogravimetric analysis of the prepared composites confirmed that MWCNTs as a thermal stabilizer for PMMA, which could have a wide range of potential applications, such as in catalysts, sensors, environmental remediation, and energy storage. Two series of poly(lactic acid) (PLA) based biocomposites with different MMA additions and MWCNT‐PMMA composites contents were prepared with twin‐screw extruding and injection molding. The results show the mechanical properties changed a little with the MMA and MWCNT‐PMMA composites contents increasing, which suggested the well compatibility between MWCNT‐PMMA composites and PLA. POLYM. COMPOS., 37:503–511, 2016. © 2014 Society of Plastics Engineers  相似文献   

2.
Nanocomposites of blends of polymethylmethacrylate (PMMA) and poly(styrene‐co‐acrylonitrile) (SAN) with multi‐walled carbon nanotubes (MWCNTs) were prepared by melt mixing in a twin‐screw extruder. The dispersion state of MWCNTs in the matrix polymers was investigated using transmission electron microscopy. Interestingly enough, in most of the nanocomposites, the MWCNTs were observed to be mainly located at SAN domains, regardless of the SAN compositions in the PMMA/SAN blend and of the processing method. One possible reason for this morphology may be the π–π interactions between MWCNTs and the phenyl ring of SAN. The shift in G‐band peak observed in the Raman spectroscopy may be the indirect evidence proving these interactions. The percolation threshold for electrical conductivity of PMMA/SAN/MWCNT nanocomposites was observed to be around 1.5 wt %. Nanocomposites with PMMA‐rich composition showed higher electrical conductivity than SAN‐rich nanocomposites at a fixed MWCNT loading. The dielectric constant measurement also showed composition‐dependent behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

3.
Nanomaterials gained great importance on account of their wide range of applications in many areas. Carbon nanotubes (CNTs) exhibit exceptional electrical, thermal, gas barrier, and tensile properties and can therefore be used for the development of a new generation of composite materials. Functionalized multiwalled carbon nanotubes (MWCNTs) reinforced Polyacrylonitrile‐co‐starch nanocomposites were prepared by in situ polymerization technique. The structural property of PAN‐co‐starch/MWCNT nanocomposites was studied by X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The conductivity, tensile strength, and thermal properties of nanocomposites were measured as a function of MWCNT concentrations. The thermal stability, conductivity, and tensile strength of PAN‐co‐starch/MWCNT nanocomposites were improved with increasing concentration of MWCNTs. Oxygen barrier property of PAN‐co‐starch/MWCNT nanocomposites was calculated and it was found that, the property was reduced substantially with increase of MWCNTs proportion. The synthesized PAN‐co‐starch/MWCNT nanocomposites may used for electrostatically dissipative materials, aerospace or sporting goods, and electronic materials. © 2013 Society of Plastics Engineers  相似文献   

4.
A series of polyimide‐based nanocomposites containing polyimide‐grafted multi‐walled carbon nanotubes (PI‐g MWCNTs) and silane‐modified ceramic (aluminium nitride (AlN)) were prepared. The mechanical, thermal and electrical properties of hybrid PI‐g MWCNT/AlN/polyetherimide nanocomposites were investigated. After polyimide grafting modification, the PI‐g MWCNTs showed good dispersion and wettability in the polyetherimide matrix and imparted excellent mechanical, electrical and thermal properties. The utilization of the hybrid filler was found to be effective in increasing the thermal conductivity of the composites due to the enhanced connectivity due to the high‐aspect‐ratio MWCNT filler. The use of spherical AlN filler and PI‐g MWCNT filler resulted in composite materials with enhanced thermal conductivity and low coefficient of thermal expansion. Results indicated that the hybrid PI‐g MWCNT and AlN fillers incorporated into the polyetherimide matrix enhanced significantly the thermal stability, thermal conductivity and mechanical properties of the matrix. Copyright © 2012 Society of Chemical Industry  相似文献   

5.
Poly(ethylene terephthalate) (PET) nanocomposites reinforced with multiwall carbon nanotubes (MWCNTs) were prepared through melt compounding in a twin‐screw extruder. The presence of MWCNTs, which acted as good nucleating agents, enhanced the crystallization of PET through heterogeneous nucleation. The incorporation of a small quantity of MWCNTs improved the thermal stability of the PET/MWCNT nanocomposites. The mechanical properties of the PET/MWCNT nanocomposites increased with even a small quantity of MWCNTs. There was a significant dependence of the rheological properties of the PET/MWCNT nanocomposites on the MWCNT content. The MWCNT loading increased the shear‐thinning nature of the polymer‐nanocomposite melt. The storage modulus and loss modulus of the PET/MWCNT nanocomposites increased with increasing frequency, and this increment effect was more pronounced at lower frequencies. At higher MWCNT contents, the dominant nanotube–nanotube interactions led to the formation of interconnected or networklike structures of MWCNTs in the PET/MWCNT nanocomposites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1450–1457, 2007  相似文献   

6.
Electrical, mechanical, and thermal properties of the poly(methyl methacrylate) (PMMA) composites containing functionalized multiwalled carbon nanotubes (f‐MWCNTs) and reduced graphene oxide (rGO) hybrid nanofillers have been investigated. The observed electrical percolation threshold of FHC is 0.8 wt% with maximum conductivity of 1.21 × 10?3 S/cm at 4 wt% of f‐MWCNTs. The electrical transport mechanism and magneto resistance studied of hybrid composites have also been investigated. Progressive addition of f‐MWCNTs in rGO/PMMA composite results increase in mechanical (tensile strength and Young's modulus) and thermal (thermal stability) properties of f‐MWCNTs‐rGO/PMMA hybrid nanocomposites (FHC). The increased mechanical properties are due to the efficient load transfer from PMMA matrix to f‐MWCNTs and rGO through better chemical interaction. The strong interaction between PMMA and f‐MWCNTs‐rGO in FHC is the main cause for improved thermal stability. POLYM. ENG. SCI., 59:1075–1083, 2019. © 2019 Society of Plastics Engineers  相似文献   

7.
Polymer nanocomposites reinforced with multi‐walled carbon nanotubes (MWCNTs) have been newly introduced for semiconducting layers of high‐voltage electrical power cables. Homogeneity of the MWCNT‐reinforced polymer nanocomposites was achieved by solution mixing, and their mechanical, thermal and electrical properties were investigated depending on the type of polymer. By changing the polymer matrix, the volume resistance of the MWCNT‐reinforced polymer nanocomposites could be varied by more than four orders of magnitude. Through systematic experiments and analysis, two possible factors affecting the volume resistance were found. One is the degree of crystallinity of the polymer used and the other is the change of MWCNT morphology under strain. By increasing the degree of crystallinity above a certain level, the volume resistance linearly increased. The MWCNTs embedded in the nanocomposites gradually protruded through the surface on stretching the sample and reversibly returned back to the original positions at a relatively small strain (below 20%). Based on the criteria of tensile properties and volume resistance, a poly[ethylene‐co‐(ethyl acrylate)]/MWCNT nanocomposite was selected as the best candidate for the semiconducting layers of high‐voltage electrical power cables. Copyright © 2009 Society of Chemical Industry  相似文献   

8.
Poly (o‐anisidine) (POA) ‐ Multi‐walled carbon nanotube (MWCNT) nanocomposites were synthesized by simple in‐situ chemical oxidative technique. Synthesized nanocomposites were characterized for their structure, morphology, thermal and electrical properties. Spectral studies indicated the presence of interactions between poly (o‐anisidine) and the surface of MWCNTs. Conductivity of 2.82 × 10−2 S cm−1 was obtained for POA‐MWCNT nanocomposite sample containing 21.2% wt. of POA. POA‐MWCNT nanocomposites thus synthesized were incorporated into epoxy based coating formulation and its anticorrosion property was studied. The coatings were also characterized by physicochemical as well as physicomechanical studies. The aim of this study was to develop a facile method for the eco‐friendly synthesis of fillers having better dispersing properties for coating having superior corrosion protective properties. POLYM. COMPOS., 36:1477–1485, 2015. © 2014 Society of Plastics Engineers  相似文献   

9.
The homogenous nanocomposite films of UV/O3 oxidized multiwall carbon nanotubes (MWCNTs) subsequently modified with aniline moiety were synthesized with polymethylmethacrylate (PMMA) through free radical polymerization. The phenylamine functional groups present on the surface of MWCNTs providing an anchoring sites for deposition of Ag metal nanoparticles (NP).The in situ free radical polymerization of MMA in the presence of these well dispersed nanotubes gave a new class of radiation resistant nanocomposite films. The synthesized materials were characterized by FT‐IR, TGA, TEM, EDX, TC, DMA, universal testing machine, and optical microscopy to ascertain their structural morphologies, thermal stability, and mechanical strength. The microscopic and structural properties reflect the homogenous mixing of modified MWCNTs in polymer matrix contributing in enhancement of thermal stability, thermo‐mechanical strength, glass transition temperatures, and thermal conductivity of nanocomposites even at 0.25 wt% addition of modified nanofiller. Thermal and thermo‐mechanical behavior of pre‐ and post‐UV/O3 irradiated nanocomposite films have been compared with neat polymer. The results revealed that modified nanofiller network can effectively disperse the radiation and has a dramatic reinforcement effect on the nature of degradation of PMMA matrix. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers  相似文献   

10.
This study focuses on the electrical properties of polycarbonate (PC)/poly(ε‐caprolactone) (PCL)‐multiwall carbon nanotube (MWCNT) nanocomposites. MWCNTs were incorporated into thermoplastic PC matrix by simple melt blending using biodegradable PCL based concentrates with MWCNT loadings (3.5 wt%). Because of the lower interfacial energy between MWCNT and PCL, the nanotubes remain in their excellent dispersion state into matrix polymer. Thus, electrical percolation in PC/PCL‐MWCNT nanocomposites was obtained at lower MWCNT loading rather than direct incorporation of MWCNT into PC matrix. AC and DC electrical conductivity of miscible PC/PCL‐MWCNT nanocomposites were studied in a broad frequency range, 101?106 Hz and resulted in low percolation threshold (pc) of 0.14 wt%, and the critical exponent (t) of 2.09 from the scaling law equation. The plot of logσDC versus p?1/3 showed linear variation and indicated the existence of tunneling conduction among MWCNTs. At low MWCNT loading, the influence of large polymeric gaps between conducting clusters is the reason for the frequency dependent electrical conductivity. Transmission electron microscopy and field emission scanning electron microscopy showed that MWCNTs were homogeneously dispersed and developed a continuous interconnected network path throughout the matrix phase and miscibility behavior of the polymer blend. POLYM. ENG. SCI., 54:646–659, 2014. © 2013 Society of Plastics Engineers  相似文献   

11.
Room temperature vulcanized silicone rubber (RTVSR) nanocomposites were prepared by mixing of surface‐modified montmorillonite nanoclay or nano fumed silica, or both of them with RTVSR to improve thermal stability, electrical insulation, and flame retardant. Their tensile strength, elongation, swelling, and solubility properties at different doses of gamma radiation were investigated to study the effect of gamma radiation on the properties of the nanocomposites. The thermal stability, flammability properties, and volume resistivity of the nanocomposites were also investigated. The nanocomposite which containing fumed silica has the best thermal, mechanical properties, electrical insulation and fire retardancy. The thermal characteristics, namely, Tonset, T10%, Tcomp, and Tmax, of the nanocomposite sample containing fumed silica were 22, 23, 13, and 11 °C higher than those of the blank, respectively. The tensile strength (TS) increased when the radiation dose was increased up to 100 kGy, but elongation, swelling, and solubility decreased when the radiation dose was increased up to 150 kGy. It can be generally concluded that the nanocomposites containing fumed silica and irradiated to 100 kGy are characterized by having outstanding mechanical, thermal, fire retardant, and electrical insulation properties and hence, they may have wide industrial applications as good thermal and electrical insulating materials. J. VINYL ADDIT. TECHNOL., 26:354–361, 2020. © 2019 Society of Plastics Engineers  相似文献   

12.
This study describes the influence of triethylenetetramine (TETA) grafting of multi‐walled carbon nanotubes (MWCNTs) on the dispersion state, interfacial interaction, and thermal properties of epoxy nanocomposites. MWCNTs were first treated by a 3:1 (v/v) mixture of concentrated H2SO4/HNO3, and then TETA grafting was performed. Chemically grafted MWCNT/bisphenol‐A glycidol ether epoxy resin/2‐ethyl‐4‐methylimidazole nanocomposites were prepared. TETA grafting could establish the connection of MWCNTs to the epoxy matrix and transform the smooth and nonreactive MWCNT surface into a hybrid material that possesses the characteristics of both MWCNTs and TETA, which facilitates homogeneous dispersion of MWCNTs and improves nanotube‐epoxy interfacial interaction. Therefore, the impact property, glass transition temperature, thermal stability, and thermal conductivity of epoxy nanocomposites are enhanced. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers  相似文献   

13.
Novel poly(methyl methacrylate) (PMMA)/silica aerogel bimodal cellular foams were prepared by melt mixing and a supercritical carbon dioxide foaming process. The effects of the silica aerogel content on the morphologies and thermal‐insulating and mechanical properties of the foams were investigated by scanning electron microscopy, mechanical tests, and heat‐transfer analysis. The experimental results show that compared to the pure PMMA foam, the PMMA/silica aerogel microcellular foams exhibited more uniform cell structures, decreased cell sizes, and increased cell densities (the densities of the foams were 0.38–0.45 g/cm3). In particular, a considerable number of original nanometric cells (ca. 50 nm) were evenly embedded in the cell walls and on the inner surfaces of the micrometric cells (<10 μm). A 62.7% decrease in the thermal conductivity (0.072 W m−1 K−1) in comparison to that of raw PMMA after 0.5 wt % silica aerogel was added was obtained. Mechanical analysis of the PMMA/silica aerogel foams with 5 and 2 wt % silica aerogel showed that the compressive and flexural strengths were distinctly improved by 92 and 52%, respectively, and the dynamic storage moduli increased. The enhanced performance showed that with the addition of silica aerogel into PMMA, one can obtain thermal‐insulation materials with a favorable mechanical strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44434.  相似文献   

14.
In this paper, γ‐ray radiation technique was utilized to simply functionalize multi‐walled carbon nanotube (MWCNT) with amino groups. The successful amino functionalization of MWCNTs (MWCNTs‐Am) was proven and the physicochemical properties of MWCNTs before and after radiation grafting modifications were characterized using FT‐IR, X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated that the γ‐ray radiation had the visible effects on the surface properties of MWCNTs. The effects of various functionalized MWCNTs on morphological, thermal, and mechanical properties of an epoxy‐based nanocomposite system were investigated. Utilizing in situ polymerization, 1 wt% loading of MWCNT was used to prepare epoxy‐based nanocomposites. Compared to the neat epoxy system, nanocomposites prepared with MWCNT‐Am showed 13.0% increase in tensile strength, 20.0% increase in tensile modulus, and 24.1% increase in thermal decomposition temperature. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers  相似文献   

15.
The advantage of using 3D hybrid filler containing carboxylic acid functionalized multiwalled carbon nanotubes (c‐MWCNTs) and sodium dodecyl sulfate modified Ni–Al layered double hydroxide (sN‐LDH) over c‐MWCNTs and sN‐LDHs acting alone was investigated. PS/c‐MWCNT composites proved to be good for improvement of properties, but not to an appreciable level, especially in case of electrical conductivity, flame retardancy, rheology, and water vapor permeability. Hence, a combination of 0.3 wt % of c‐MWCNT and 3 wt % of sN‐LDH was optimized as additives to assist in the full expression of the filler traits in the nanocomposite and to obtain a versatile nanocomposite with properties specific to both the fillers. This approach slightly decreases the dispersion challenge faced with handling high loadings of CNT and also the intrinsic limitations specific to the individual fillers (i.e., inertness of CNTs and low conductivity of LDHs). Moreover, the anion/anionic repulsion of organically modified CNT/LDH facilitates effective dispersion of the additive opposing adhesion. FTIR and Raman spectroscopy provided evidence for incorporation and proper dispersion of the additives in the polymer matrix, with XRD and TEM confirming a well‐dispersed morphology of the nanocomposites. In this work, focus is made on the improvement of thermal stability, flame retardancy, melt rheology, hardness, electrical conductivity, and water vapor permeability of PS/0.3 wt % c‐MWCNT/3 wt % sN‐LDH nanocomposites over PS/0.3 wt % c‐MWCNT, making use of the synergistic effect of c‐MWCNT coupled with sN‐LDH on polystyrene. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46513.  相似文献   

16.
Nanocomposites of thermoplastic polyurethanes (TPUs), multiwalled carbon nanotubes (MWCNTs) and clays were prepared via melt processing using polyether‐ and polyester‐based TPUs, MWCNTs, and organically modified nanoclays (Cloisite C30B and C25A). Coaddition of clays and MWCNTs to TPU nanocomposites increased their electrical conductivities above those without any clay. Nanoclay alone is shown to produce no effect on electrical conductivity. TEM results show that the coaddition of nanoclay affects the nanocomposite morphology by changing the MWCNT distribution. Clay C25A and MWCNTs were observed to form network structures in the nanocomposites, resulting in improved electrical conduction. Interaction between MWCNTs and clays as well as an increase in nanocomposite viscosity caused by the coaddition of clays may influence the morphology change. Most of the nanocomposites containing both MWCNTs and clay exhibited higher dielectric constants, indicating higher electrical conductivities. Tensile properties investigations confirmed the reinforcing effects of the MWCNTs and clays. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

17.
The preparation of thermoplastic nanocomposites of waterborne polyurethane (WBPU) and multiwall carbon nanotubes (MWCNTs) via an in situ polymerization approach is presented. The effects of the presence and content of MWCNTs on the morphology and thermal, mechanical and electrical properties of the nanocomposites were investigated. Carbon nanotubes were modified with amide groups in order to enhance their chemical affinity towards WBPU. Thermogravimetric studies show enhanced thermal stability of the nanocomposites. Scanning and transmission electronic microscopy images prove that functionalized carbon nanotubes can be effectively dispersed in WBPU matrix. Mechanical properties reveal that Young's modulus and tensile strength tend to increase when appropriate amounts of MWCNTs are loaded due to the reinforcing effect of the functionalized carbon nanotubes. Thermal properties show an increase in the glass transition temperature and storage modulus with an increase in MWCNT content. X‐ray diffraction reveals better crystallization of the WBPU in the presence of MWCNTs. The WBPU/MWCNT nanocomposite film containing 1 wt% of MWCNTs exhibits a conductivity nearly five orders of magnitude higher than that of WBPU film. © 2017 Society of Chemical Industry  相似文献   

18.
The use of multi‐walled carbon nanotubes (MWCNT) as reinforcing material for thermoplastic polymer matrices, polymethyl methacrylate (PMMA), and polystyrene (PS) has been studied. MWCNT were synthesized by chemical vapor deposition (CVD) technique using ferrocene‐toluene mixture. As‐prepared nanotubes were ultrasonically dispersed in toluene and subsequently dispersed in PMMA and PS. Thin polymer composite films were fabricated by solvent casting. The effect of nanotube content on the electrical and mechanical properties of the nanocomposites was investigated. An improvement in electrical conductivity from insulating to conducting with increasing MWCNT content was observed. The carbon nanotube network showed a classical percolating network behavior with a low percolation threshold. Electromagnetic interference (EMI) shielding effectiveness value of about 18 dB was obtained in the frequency range 8.0–12 GHz (X‐band), for a 10 vol% CNT loading. An improved composite fabrication process using casting followed by compression molding and use of functionalized MWCNT resulted in increased composites strength. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers  相似文献   

19.
Ethylene‐vinyl acetate copolymer (EVA) was melt‐mixed with multiwalled carbon nanotubes (MWCNTs) and organoclays, and the effects of simultaneous use of organoclays and MWCNTs on the surface resistivity and tensile properties of EVA nanocomposites were investigated. The surface resistivity of EVA/MWCNT nanocomposite with 1 phr of MWCNT is out of our measurement range (above 1012 Ω/square). With increasing content of organoclay from 0 to 3 phr, the surface resistivity of the EVA/MWCNT/organoclay nanocomposites with 1 phr MWCNT remains out of our measurement range. However, the surface resistivity of the nanocomposite decreases to 106 Ω/square with addition of 5 phr organoclay. The tensile properties of EVA/MWCNT/organoclay nanocomposites with 1 phr MWCNT and 5 phr organocaly are similar to those of EVA/MWCNT nanocomposites with 5 phr MWCNT except tensile modulus. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers  相似文献   

20.
We demonstrate a method that involves melt blending of polycarbonate (PC) and melt‐blended acrylonitrile butadiene styrene (ABS) with multiwall carbon nanotubes (MWCNTs) to prepare electrically conducting PC/MWCNT nanocomposites at significantly low MWCNT loading. The partial solubility of ABS in PC led to a selective dispersion of the MWCNTs in the ABS phase after melt‐blending PC and ABS. Thus, a sudden rise in electrical conductivity (∼108 orders of magnitude) of the nanocomposites was found at 0.328 vol% of MWCNT, which was explained in terms of double percolation phenomena. By optimizing the ratio of PC and the ABS–MWCNT mixture, an electrical conductivity of 5.58 × 10−5 and 7.23 × 10−3 S cm−1 was achieved in the nanocomposites with MWCNT loading as low as 0.458 and 1.188 vol%, respectively. Transmission electron microscopy revealed a good dispersion and distribution of the MWCNTs in the ABS phase, leading to the formation of continuous MWCNT network structure throughout the matrix even at very low MWCNT loading. Storage modulus and thermal stability of the PC were also increased by the presence of a small amount of MWCNTs in the nanocomposites.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers  相似文献   

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