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1.
Calcium carbonate nanoparticles (nano‐CaCO3) anchored graphene oxide (GO) sheet nanohybrids (GO‐CaCO3) are fabricated, and their structure can be measured by scanning electron microscope, transmission electron microscopy, X‐ray photoelectron spectroscopy, X‐ray diffraction and Fourier‐transform infrared spectroscopy analysis. Afterwards, composite epoxy coatings, filled with GO and GO‐CaCO3 nanohybrids, are prepared via a curing process. The dispersion and anticorrosive properties of composite epoxy coatings are investigated. The results reveal that GO‐CaCO3 nanohybrids achieve a homogeneous dispersion as well as reinforce corrosion resistance of epoxy coatings. Furthermore, the anticorrosive mechanisms are tentatively proposed for the GO‐CaCO3/epoxy coatings. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

2.
In this work, a highly dispersed graphene oxide (GO) was successfully functionalized with 3‐mercaptopropyltrimethoxysilane (MPTS) molecule by silanization method. The chemically generated GO and MPTS functionalized GO (MPTS‐GO) were structurally characterized by thermogravimetric analysis (TGA), X‐ray diffraction analysis (XRD), scanning electron microscope (SEM), energy dispersive X‐ray (EDAX), fourier transform infrared spectroscopy (FT‐IR) and ultraviolet visible spectroscopy (UV‐Vis) techniques. The MPTS‐GO is highly suspensable in water. The thermal and conductivity results for MPTS‐GO are significantly increased compared to GO. Moreover, glassy carbon electrode modified with MPTS‐GO hybrid (MPTS‐GO/GCE) was prepared by casting of the MPTS‐GO solution on GCE. The MPTS‐GO/GCE showed an excellent electrocatalytic activity towards methionine (Met). This was understood from the observed less positive oxidation potential and higher oxidation current when compared to bare GC electrode. The MPTS‐GO has excellent electrocatalytic activity, making it an ideal candidate for sensor applications.  相似文献   

3.
Poly(propylene) (PP)/PP grafted styrene‐butadiene rubber (PP‐g‐SBR) nanocomposite was prepared by blending PP with PP‐g‐SBR using dynamical photografting. The crystal morphological structure, thermal behavior, and mechanical properties of PP/PP‐g‐SBR nanocomposites have been studied by photoacoustic Fourier transform infrared spectroscopy (PAS‐FT‐IR), wide‐angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and mechanical measurements. The data obtained from the mechanical measurements show that the PP‐g‐SBR as a modifier can considerably improve the mechanical properties of PP/PP‐g‐SBR nanocomposites, especially for the notched Izod impact strength (NIIS). The NIIS of the nanocomposite containing 2 wt% PP‐g‐SBR measured at 20°C is about 2.6 times that of the control sample. The results obtained from PAS‐FTIR, WAXD, SEM, and DSC measurements revealed the enhanced mechanism of impact strength of PP/PP‐g‐SBR nanocomposites as follows: (i) the β‐type crystal of PP formed and its content increased with increasing the photografting degree of PP‐g‐SBR; (ii) the size of PP‐g‐SBR phase in the PP/PP‐g‐SBR nanocomposites obviously reduced and thus the corresponding number of PP‐g‐SBR phase increased with increasing the photografting degree of PP‐g‐SBR. All the earlier changes on the crystal morphological structures are favorable for increasing the compatibility and enhancing the toughness of PP at low temperature. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

4.
Polymethacrylamide/Na‐montmorillonite nanocomposites have been prepared by free‐radical polymerization. All the nanocomposites were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and differential thermal analysis. The thermal properties of nanocomposites are notably improved by the presence of the montmorillonite layers in comparison with pure polymethacrylamide. X‐ray diffraction and scanning electron microscopy confirmed that polymethacrylamide could be easily inserted between the layers of Na‐montmorillonite to form intercalated nanocomposites, and significantly large d‐spacing expansions from 1.19 to 2.93 nm of the nanocomposites. Adsorptive properties of nanocomposites were also investigated.  相似文献   

5.
Attempts have been made to evaluate the effect of interface and degree of interfacial interaction upon electrical conductivity threshold in polypropylene/expanded graphite (PP/EG) nanocomposites, and dispersion state of graphite nanosheets. For this purpose, maleic anhydride grafted polypropylene (PPgMA) and maleic anhydride grafted EPDM (EPDMgMA) were used as compatibilizer. Nanocomposite samples containing 1–5 vol% of EG were prepared by melt mixing method using laboratory scale internal mixer. Characterization was carried out by using X‐ray diffraction (XRD), differential scanning calorimeter (DSC), thermo‐gravimetric analysis (TGA), scanning electron microscope (SEM), transmission electron microscope (TEM), and rheo‐mechanical spectroscopy (RMS). The conductivity measurements were carried out by using four point probe method according to ASTM D991. Results showed that the conductivity threshold is controlled by the extent of interfacial interaction between PP and EG. So, better conductivity was obtained using PPgMA as compatibilizer which causes higher level of interaction between PP and EG, and therefore better dispersion of the EG nanolayers in the polymer matrix. On the other hand, high levels of compatibilizers, especially EPDMgMA, caused formation of separated aggregates of EG shelled with the compatibilizer, which results in the reduction of conductivity of the nanocomposites. This finding has been verified by SEM, RMS, and conductivity measurements. Effects of EG nanolayers on crystalline structure and thermal decomposition temperature of the nanocomposites have also been investigated by DSC and TGA, respectively. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

6.
A novel method is described for the preparation of nanocomposites comprising a high performance rubber for tire application and layered silicates clay. In this work nanocomposites of solution‐styrene butadiene rubber (S‐SBR) with montmorillonite layered silicate were prepared with carboxylated nitrile rubber (XNBR), a polar rubber, as a compatibilizer. A sufficient amount of organomodified layered silicate was loaded in carboxylated nitrile rubber (XNBR) and this compound was blended as a master batch in the S‐SBR. Mixed intercalated/exfoliated morphologies in the nanocomposite are evinced by X‐ray diffraction measurements and transmission electron microscopy. Dynamic mechanical analysis also supports the compatibility of the composites. A good dispersion of the layered silicate in the S‐SBR matrix was reflected from the physical properties of the nanocomposites, especially in terms of tensile strength and high elongation properties.  相似文献   

7.
Ag/MnO2/GO nanocomposites were synthesized via the method of gas/liquid interface based on silver mirror reaction, and a non‐enzymatic H2O2 sensor was fabricated through immobilizing Ag/MnO2/GO nanocomposites on GCE. The composition and morphology of the nanocomposites were studied by energy‐dispersive X‐ray spectroscopy (EDS), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Electrochemical investigation indicated that it exhibited a favorable performance for the H2O2 detection. Its linear detection range was from 3 μM to 7 mM with a correlation coefficient of 0.9960; the sensitivity was 105.40 μA mM?1 cm?2 and the detection limit was estimated to be 0.7 μM at a signal‐to‐noise ratio of 3.  相似文献   

8.
Herein we report an easy and efficient approach to prepare lightweight porous polyimide (PI)/reduced graphene oxide (RGO) composite films. First, porous poly (amic acid) (PAA)/graphene oxide (GO) composite films were prepared via non‐solvent induced phase separation (NIPS) process. Afterwards PAA was converted into PI through thermal imidization and simultaneously GO dispersed in PAA matrix was in situ thermally reduced to RGO. The GO undergoing the same thermal treatment process as thermal imidization was characterized with thermogravimetric analysis, Raman spectra, X‐ray photoelectron spectroscopy and X‐ray diffraction to demonstrate that GO was in situ reduced during thermal imidization process. The resultant porous PI/RGO composite film (500‐µm thickness), which was prepared from pristine PAA/GO composite with 8 wt% GO, exhibited effective electrical conductivity of 0.015 S m?1 and excellent specific shielding efficiency value of 693 dB cm2 g?1. In addition, the thermal stability of the porous PI/RGO composite films was also dramatically enhanced. Compared with that of porous PI film, the 5% weight loss temperature of the composite film mentioned above was improved from 525°C to 538°C. Moreover, tensile test showed that the composite film mentioned above possessed a tensile strength of 6.97 MPa and Young's modulus of 545 MPa, respectively. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

9.
In this report, we demonstrate that both the thermal stability and the thermal conductivity of bromobutyl rubber (BIIR) nanocomposites could be improved by incorporating the ionic liquids (ILs) modified graphene oxide (GO-ILs) using a solution compounding method. The structure, thermal stability and thermal conductivity of this newly modified BIIR nanocomposites were systematically analyzed and studied. The X-ray diffraction (XRD) analysis of GO-ILs showed that ILs had been effectively intercalated into the interlayer of GO, which was found to be able to raise the exfoliation degree of GO. The increased exfoliation degree facilitated a good dispersion of GO-ILs in the BIIR matrix, as revealed by the scanning electron microscope (SEM) images. The glass transition temperatures (Tg) of the GO-ILs/BIIR nanocomposites were also raised by the addition of GO-ILs, which indicates the strong interfacial adhesion between GO-ILs and the rubber. Most importantly, the incorporation of GO-ILs in the BIIR matrix could effectively improve the thermal stability of the rubber nanocomposites according to our thermogravimetric analysis (TGA). The activation energy (Ea) of thermal decomposition of GO-ILs/BIIR nanocomposites increases with the addition of GO-ILs. Besides, the thermal conductivity of GO-ILs/BIIR nanocomposite with 4 wt% of GO-ILs had 1.3-fold improvement compared to that of unfilled BIIR.  相似文献   

10.
A group of shape memory polyurethane‐based nanocomposites containing graphene quantum dot nanoparticles (GQDs) were prepared via in‐situ polymerization method. GQD nanoparticles were synthesized by a facile and rapid microwave‐assisted method and characterized by Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction pattern, field emission scanning microscopy, transmission electron microscopy, and fluorescence analysis. Chemical structure and hydrogen bonding index (HBI[C=O]) of the nanocomposites were analyzed via FTIR spectra. The results show that the incorporation of GQDs in PU matrix reduces HBI(C=O) of nanocomposites. Crystalline structure and thermal properties of the nanocomposites were investigated by differential scanning calorimetry. As results indicate, nucleation effect of GQDs raises crystallinity content of the samples. Mechanical examinations indicate that incorporation of GQDs improves Young's modulus of the nanocomposites, while their elongation at break values are reduced. In addition, shape memory analyses reveal that the presence of GQDs in PU matrix increases the shape fixity ratios in nanocomposites.  相似文献   

11.
《先进技术聚合物》2018,29(8):2165-2173
Novel chlorinated acrylonitrile butadiene rubber (Cl‐NBR) was prepared from NBR by the alkaline hydrolysis of chloroform by using phase‐transfer catalysis. The formation of Cl‐NBR was monitored by 1H‐NMR, UV‐Vis, and Fourier transform infrared spectroscopic techniques. The percentage of chlorine attached to the rubber chain was estimated by Volhard method. The effect of polar groups on the structural and thermal properties of Cl‐NBR was analyzed by scanning electron microscopy, X‐ray diffraction analysis, differential scanning calorimetry, and thermogravimetric analysis studies. The flame retardant, oil resistance, cure behavior, and mechanical properties of chlorinated elastomer were also analyzed. The proton NMR revealed the attachment of chlorine in the backbone of NBR with new chemical shift values. The C‐Cl stretching of chlorinated NBR was confirmed from Fourier transform infrared. The UV spectrum also supported the formation of chlorinated unit in the NBR chain through the shifts and broadening of absorption peaks. The X‐ray diffraction analysis pattern indicated a decrease in the amorphous domain of NBR with an increase in the level of chemical modification. The increased glass transition temperature obtained from differential scanning calorimetry confirms the increased molecular rigidity of the chlorinated NBR and thermal transitions increased with increase in the level of chemical modification. The thermal stability of Cl‐NBR decreased with an increase in chlorine content. The flame and oil resistance of Cl‐NBR was greatly higher than pure NBR due to the increased polarity of modified rubber. The superior tensile strength of Cl‐NBR (4 times higher than pure NBR) and higher oil resistance find applications in pump diaphragms, aircraft hoses, oil‐lined tubing, and gaskets materials with the excellent flame resistant property.  相似文献   

12.
In this work, preparation and properties of different nanoclays modified by organic amines (octadecyl amine, a primary amine, and hexadecyltrimethylammonium bromide, a tertiary amine) and brominated polyisobutylene‐co‐paramethylstyrene (BIMS)‐clay nanocomposites are reported. The clays and the rubber nanocomposites have been characterized with the help of Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X‐ray diffraction (XRD). The X‐ray diffraction peaks observed in the range of 3 °–10 ° for the modified clays disappear in the rubber nanocomposites. TEM photographs show predominantly exfoliation of the clays in the range of 12 ± 4 nm in the BIMS. In the FTIR spectra of the nanocomposites, there are common peaks of virgin rubber as well as those of the clays. Excellent improvement in mechanical properties like tensile strength, elongation at break, and modulus is observed on incorporation of the nanoclays in the BIMS. Structure‐property correlation in the above nanocomposites is attempted. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4489–4502, 2004  相似文献   

13.
Novel radiation shielding nanocomposites based on a conducting polymer were fabricated and investigated to determine their abilities in attenuation of X‐rays. Polypyrrole/Pb nanocomposites were prepared through chemical reduction of lead salt by a facile solution‐phase method using t‐BuOLi‐activated LiH and in situ chemical polymerization of pyrrole in the presence of dodecyl benzene sulfonic acid as dopant and surfactant and iron chloride as the oxidant. The morphology, composition, and electrical conductivity of resulting products were characterized by scanning electron microscopy, transmission electron microscopy, X‐ray diffraction analysis, energy‐dispersive X‐ray spectroscopy, fourier transform infrared spectroscopy, and standard four‐wire technique, respectively. In order to evaluate capability of nanocomposites in radiation shielding, X‐ray photon interaction parameters such as linear attenuation coefficient, attenuation percentage, and half‐value thickness were determined for the samples with different Pb loadings and thicknesses, at photon energies of 13.95, 17.74, 20.08, 26.34, and 59.50 keV. The investigation was carried out to explore the potential of polypyrrole/Pb nanocomposites as thin and light‐weight radiation shielding materials. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

14.
Polystyrene sulfonic acid (PSSA) doped water‐soluble polyaniline (PANI)/montmorillonite (MMT) clay composites were synthesized by intercalation polymerization in aqueous medium. The properties of the composites were characterized by X‐ray diffraction (XRD), transmission electron microscope (TEM), Fourier‐transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray photoelectron spectroscopy (XPS) and conductivity measurement. The results show that the composite has a mixed nanomorphology and exfoliated silicate nanolayers of MMT clay dispersed in the polyaniline matrix. This composite is more thermal stable than that without clay samples and results in good stable temperature‐dependent dc conductivity [σdc(T)] as temperature changed.  相似文献   

15.
The present study deals with the structure–property relationship of organoclay (OC) filled nanocomposites based on rubber blend comprising of nitrile‐butadiene rubber (NBR) and phenolic resin (PH). To obtain a better insight into the characteristics of the NBR/PH/OC hybrid system, a simple model system consisting of NBR/OC nanocomposites is also taken into consideration. A series of NBR/OC and NBR/PH/OC nanocomposites containing a wide range of OC concentrations (2.5–30 phr) are prepared by using traditional open two‐roll mill. Structural analysis performed by X‐ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) exhibits mixed exfoliated and intercalated morphology at low OC content, below 7.5 phr, and a well‐ordered intercalated morphology at higher OC loading. It is shown that the dispersion of OC is also influenced by mixing time and order of mixing of components. Analysis of the cure characteristics, mechanical, and thermal properties of both the NBR/OC and NBR/PH/OC nanocomposites reveals that the OC is dispersed mainly in the NBR continuous phase, even though some is likely localized in the rubber–resin interface. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

16.
Microbial desulfurization of waste tyre rubber has been investigated with great efforts since 1990s, because waste rubber has created serious ecological and environmental problems. A microbial desulfurization technique for SBR ground rubber has been developed by a novel sulfur‐oxidizing bacterium Sphingomonas sp. The adaptability of Sphingomonas sp. with SBR ground rubber was tested with the amounts of SBR ground rubber varying from 0.5 to 4% g/l. The sol fraction of desulfurized SBR ground rubber increased 70%, compared with SBR ground rubber without desulfurization. Fourier transform infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR) spectrum and X‐ray photoelectron spectroscopy (XPS) analysis of the desulfurized surface of vulcanized SBR flakes revealed that not only the oxidation of crosslinked S? S and S? C bonds, but also the rupture of C?C double bonds had happened to SBR vulcanizates during microbial desulfurization. The cure characteristics, such as scorch time and optimum cure time of natural rubber (NR) vulcanizates filled, were found to decrease with increasing contents of desulfurized SBR ground rubber, due to some reactive groups on its surface. NR vulcanizates filled with desulfurized SBR ground rubber had lower crosslink density and hardness, higher tensile strength and elongation at break, compared with those filled with SBR ground rubber of the same amount. Dynamic mechanical properties indicated that there were better crosslink distribution and stronger interfacial bonding between NR matrix and desulfurized SBR ground rubber. Scanning electron microscope (SEM) photographs showed that the fracture surfaces of NR vulcanizates filled with desulfurized SBR ground rubber had more smooth morphologies. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

17.
Functionalized carbon nanotubes (F‐CNTs) were synthesized through the nucleophilic substitution reaction between four‐armed star poly(d ‐lactide) (4PDLA) and acryl chloride of carbon nanotubes and were characterized using Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy and thermogravimetric analysis. The results indicated that the 4PDLA was successfully grafted onto carbon nanotubes, and it contained 45.5 wt% of 4PDLA. Poly(l ‐lactide) (PLLA) nanocomposites with different F‐CNTs content were prepared by solution casting. Optical microscopy and scanning electron microscopy results showed that F‐CNTs were uniformly dispersed in the nanocomposites. Crystallization behavior and crystal structure of PLLA nanocomposites were investigated using differential scanning calorimetry, polarizing microscope and X‐ray diffraction. The results found that poly(lactide) stereocomplex crystal could be formed between PLLA and F‐CNTs. F‐CNTs played different roles in the process of solution casting and melting crystallization. Polarizing microscope also revealed that crystallization temperature had a significant effect on the nucleation and spherulites growth of PLLA. Thermal stability and mechanical properties of the nanocomposites were also investigated by thermogravimetric analysis, dynamic mechanical analysis and tensile testing. These results demonstrated that the addition of F‐CNTs obviously improved thermal stability and tensile strength of PLLA. The results showed that PLLA/F‐CNTs would have potential values in engineering fields. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

18.
Poly [styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS)/sepiolite clay nanocomposites are prepared by solvent casting method. Two types of schemes have been adopted to establish the compatibility between nonpolar polymer (SEBS) and needle‐like inorganic filler (sepiolite), either by polar modification of the nonpolar polymer or organic modification of the inorganic filler. Structure–property correlation of nanocomposites derived from two different approaches is compared. Structural and morphological analysis of nanocomposites has been investigated by Fourier transform infrared spectroscopy, X‐ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. Fourier transform infrared result shows better compatibility between SEBS and modified sepiolite clay compared to maleic anhydride grafted SEBS and pristine sepiolite in their nanocomposites. Tensile strength and % elongation are found to increase by 32 and 105%, respectively, with the addition of just 3 parts per hundred parts of resin (phr) modified sepiolite clay to pristine SEBS matrix. Moreover, thermal stability has also improved by 96°C with similar loading. This work provides a new insight into the structure and thermo‐mechanical properties of novel SEBS–sepiolite clay nanocomposites. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

19.
Polyaniline (PANI)‐montmorillonite (MMT) nanocomposites were prepared by direct intercalation of aniline molecules into MMT galleries, followed by in situ polymerization within the nano‐interlamellar spaces under solvent‐free conditions. The basal spacing of aniline‐intercalated MMT increased gradually up to 1.5 nm with increasing amounts of aniline loaded. This result suggests that aniline molecules were adsorbed by MMT clay and that intercalated aniline likely located perpendicular to the silicate sheets. After polymerization, X‐ray diffraction and Fourier transform infrared analyses confirmed the successful synthesis of PANI chains between the MMT nano‐interlayers. The scanning electron microscopy images indicated that the surface morphologies of PANI–MMTs were strongly different depending on the PANI content. The electrical conductivities of PANI nanocomposite particles in pressed pellets ranged in the order of between 10?3 and 10?2 S/cm. UV–vis spectroscopy and doping level measurement were further used to discuss the conductivities of nanocomposites. The thermal stabilities of PANI–MMT nanocomposites were examined by using thermogravimetric‐differential thermal analysis and derivative thermogravimetric analysis, and both analyses consequently demonstrated the improved thermal stabilities of the PANI chains in the nanocomposites as compared to pure PANI. The thermal stabilities of resulting nanocomposites were strongly related to the PANI content, which increased as the PANI content decreased in the nanocomposites. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2705–2714, 2005  相似文献   

20.
We report the synthesis of ionic liquid‐functionalized mesoporous silica nanoparticles ([pmim]FeCl4/MSNs) via a method of post‐grafting on parent MSNs. This hybrid material was characterized using scanning and transmission electron microscopies, energy‐dispersive X‐ray spectroscopy, nitrogen adsorption–desorption analysis, Fourier transform infrared spectroscopy, powder X‐ray diffraction and thermal analyses. The material was utilized as an efficient heterogeneous catalyst for the synthesis of N ,N ′‐diaryl‐substituted formamidines through the reaction of triethyl orthoformate with arylamines under solvent‐free conditions. The catalyst was recovered easily and reused several times without significant loss of its catalytic activity.  相似文献   

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