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1.
The mechanical and fracture properties of vinyl‐ester composites reinforced with halloysite nanotubes have been investigated. Enhancements in toughness are attributed to crack bridging, deflection, and localized plastic deformation, while strength improvements can be attributed to the large aspect ratio of fillers, favorable interfacial adhesion and dispersion, and inter‐tubular interaction. Comparisons of experimental data on elastic modulus and mathematical models for predicting particulate polymer composites have verified the models of Paul and Guth. The aspect ratio of fillers and the degree of interfacial adhesion are crucial factors in the prediction of elastic modulus in these polymer nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1716–1725, 2013  相似文献   

2.
A chemically modified sensor based on the synergistic effect of graphene and polyaniline for electrochemical sensing of calcium antagonist lercanidipine (LCP) has been developed. Scanning electron microscopy, electrochemical impedance spectroscopy, square‐wave voltammetry, and cyclic voltammetry were utilized to characterize the morphology and electroanalytical performance of the fabricated sensor. Under optimized conditions, reduction peak current was linear over the wide concentration range from 5 to 125 ng mL?1 with correlation coefficient of 0.9998. The limit of detection and the limit of quantification were found to be 1.94 and 5.89 ng mL?1. The developed sensor also exhibited good reproducibility and long‐term stability. In addition, the proposed method was successfully applied to the determination of LCP in pharmaceutical formulation which is proved by recovery studies. Graphene–polyaniline composites are expected to be promising material for biosensing applications because of the ease of fabrication, excellent electrochemical performance, and high electroactive surface area. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40959.  相似文献   

3.
Polyaniline (PANI)/reduced graphene oxide (rGO) composites were synthesized by in situ oxidative polymerization of aniline on reduced graphene sheets. Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, transmission electron microscopy, and scanning electron microscopy were used to characterize the composites. The results indicated PANI/rGO composites were produced and contained covalent bonds between the functional groups of PANI and rGO. A uniform coating of PANI on the rGO sheets had a synergistic effect on the properties of the composites. The electrochemical properties of the PANI/rGO composites produced using different feed ratios of aniline to rGO were studied. The results showed that the composites exhibited a maximum specific capacitance of 797.5 F/g at 0.5 A/g and minimum charge transfer resistance of 0.98 Ω when the feed ratio of aniline to rGO was 2:1. These values were superior to those of pure PANI and rGO. The composites also displayed excellent cycling stability, with specific capacitance retention of 92.43% after 1000 cycles. These stable structural composites show promise for the development of new supercapacitor applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46103.  相似文献   

4.
This article describes the synthesis and characterization of highly conductive polypyrrole (PPy)/multiwalled carbon nanotube (MWCNT) composites prepared by in situ polymerization of pyrrole using 5‐sulfoisophthalic acid monolithium salt [lithio sulfoisophthalic acid (LiSiPA)] as dopant and ferric chloride as oxidant. Several samples were prepared by varying the amounts of MWCNTs ranging from 1 to 5 wt %. Scanning electron microscope and transmission electron microscope images clearly show a thick coating of PPy on surface of MWCNTs. The electrical conductivity of PPy increased with increasing amount of MWCNTs and maximum conductivity observed was 52 S/cm at a loading of 5 wt % of MWCNTs. Pure PPy prepared under similar conditions had a conductivity of 25 S/cm. Electromagnetic interference (EMI) shielding effectiveness (SE) also showed a similar trend and average EMI shielding of ?108 dB (3 mm) was observed for sample having 5 wt % MWCNT in the frequency range of 8.2–12.4 GHz (X‐band). The light weight and absorption dominated total SE of ?93 to ?108 dB of these composites indicate the usefulness of these materials for microwave shielding. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45370.  相似文献   

5.
An experimental study is carried out to quantitatively assess the dispersion quality of carbon nanotubes (CNTs) in epoxy matrix as a function of CNT variant and weight fraction. To this end, two weight fractions (0.05% and 0.25%) of as-grown, oxidized, and functionalized CNTs are used to process CNT/epoxy nanocomposites. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared analysis of different variants of CNTs are used to establish the efficiency of purification route. While the relative change in mechanical properties is investigated through tensile and micro-hardness testing, thermal conductivity of different nanocomposites is measured to characterize the effect of CNT addition on the average thermal properties of epoxy. Later on, a quantitative analysis is carried out to establish the relationship between the observed improvements in average composite properties with the dispersion quality of CNTs in epoxy. It is shown that carboxylic (-COOH) functionalization reduces the average CNT agglomerate size and thus ensures better dispersion of CNTs in epoxy even at higher CNT weight fraction. The improved dispersion leads to enhanced interfacial interaction at the CNT/epoxy interface and hence provides higher relative improvement in nanocomposite properties compared to the samples prepared using as-grown and oxidized CNTs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48879.  相似文献   

6.
This work describes an empirical study of in situ interfacial dynamic inverse emulsion polymerization process under sonication of aniline in the presence of nine different types of carbon nanotubes (CNT) in toluene. The polymerization method described in this work is simple and very fast (5 min) compared to the other literature reports (3–12 h). During polymerization, CNT are coated with polyaniline (PANI) forming a core‐shell structure of nanowires as evidenced by transmission electron microscopy (TEM) and high‐resolution scanning microscopy (HRSEM). HRSEM images and surface resistivity imply that PANI coating of CNT leads to a remarkable improvement in separation and dispersion of CNT in toluene, which otherwise would have rapidly coagulate and settle. Two of the nine different CNT studied have shown the lowest surface resistivities. Films of uniform thickness were successfully produced (HRSEM of cross‐sections). The effect of film thickness on conductivity and optical properties is reported in the work. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

7.
A novel monomer, 2,6‐di(thiophene‐2‐yl)‐3,5bis(4‐(thiophene‐2‐yl)phenyl)dithieno[3,2‐b;2',3'‐d]thiophene ( Th4DTT) has been synthesized and used as an electro‐active material. It has been electropolymerized onto glassy carbon (GC) electrode in sodium dodecyl sulfate (SDS) solution (0.1 M) together with multi‐walled carbon nanotubes (MWCNT). A good capacitive characteristics for P(Th4DTT)/MWCNT composite has been obtained by electrochemical impedance spectroscopy (EIS), which is, to our best knowledge, the first report on capacitor behavior of a dithienothiophene. A synergistic effect has been resolved by Nyquist, Bode‐magnitude—phase and admittance plots. Specific capacitance of the conducting polymer/MWCNT, calculated from cyclic voltammogram (CV) together with area and charge formulas, has been found to be 20.17 F g?1. Long‐term stability of the capacitor has also been tested by CV, and the results indicated that, after 500 cycles, the specific capacitance is 87.37% of the initial capacitance. An equivalent circuit model of Rs(C1(R1(Q(R2W))))(C2R3) has been obtained to fit the experimental and theoretical data. The double layer capacitance (Cdl) value of P(Th4DTT)/MWCNT (4.43 mF cm?2) has been found to be 25 times higher than P(Th4DTT) (Cdl= 0.18 mF cm?2). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40061.  相似文献   

8.
In this work, multi‐walled carbon nanotubes (MWCNT) and poly(methyl methacrylate) (PMMA) pellets were compounded via corotating twin‐screw extruder. The produced MWCNT/PMMA nanocomposite pellets were injection molded. The effect of MWCNT concentration, injection melt temperature and holding pressure on mechanical properties of the nanocomposites were investigated. To examine the mechanical properties of the MWCNT/PMMA nanocomposites, tensile test, charpy impact test, and Rockwell hardness are considered as the outputs. Design of experiments (DoE) is done by full factorial method. The morphology of the nanocomposites was performed using scanning electron microscopy (SEM). The results revealed when MWCNT concentration are increased from 0 to 1.5 wt %, tensile strength and elongation at break were reduced about 30 and 40%, respectively, but a slight increase in hardness was observed. In addition, highest impact strength belongs to the nanocomposite with 1 wt % MWCNT. This study also shows that processing condition significantly influence on mechanical behavior of the injection molded nanocomposite. In maximum holding pressure (100 bar), the nanocomposites show highest tensile strength, elongation, impact strength and hardness. According to findings, melt temperature has a trifle effect on elongation, but it has a remarkable influence on tensile strength. In the case of impact strength, higher melt temperature is favorable. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43738.  相似文献   

9.
To recycle the nitrogen (N) and phosphorus (P) from wastewater, ferrum ammonium phosphate (FAP)–halloysite nanotubes (HNTs) were synthesized with simulated wastewater containing N, P, and Fe pollutants as raw materials. The adsorption–chemical precipitation in situ method was used to synthesize the target products, and the optimal conditions for the synthesis of the FAP–HNTs were obtained. Fourier transform Infrared (FTIR) spectroscopy, energy‐dispersive spectroscopy (EDS), scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis were conducted to characterize the samples. The FAP particle size was 20–30 nm in the FAP–HNTs. The FTIR spectra demonstrated that a small amount of water in the FAP–HNTs promoted the curing reaction. The FAP–HNTs and Exolit OP 1230 (OP) were introduced into epoxy (EP) to prepare the polymer nanocomposites. The heat release rate (HRR) and flammability of the EP composites were tested by microscale combustion calorimetry and UL‐94 instruments. The mechanical properties of the EP composites also were tested by a tension testing system. The results indicate that the flame retardancy and mechanical properties of the EP composites were improved by FAP–HNT. The addition of FAP–HNT and OP gave rise to an evident reduction of HRR and a prolonged burning time for the EP. EP/FAP–HNT/OP (20) (where 20 is the loading weight percentage) passed the UL 94 V‐0 rating. The analysis of the char revealed the synergy of the FAP–HNTs and OP in reducing the flammability of the polymers. We concluded that these polymers show potential for applications in wastewater treatment and N/P recycling. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41681.  相似文献   

10.
A chemical sensor for methyl viologen (MV2+), based on a water‐soluble conjugated polymer/single‐walled carbon‐nanotube (SWNT) composite, was fabricated. Water‐soluble poly(m‐phenylene ethynylene) with sulfonic acid side‐chain groups (mPPE‐SO3) was synthesized via a Pd‐catalyzed Sonogashira coupling reaction and used to prepare a highly stable mPPE‐SO3/SWNT composite with strong π–π interactions in water. The relationship between the optical properties and sensing capability of the mPPE‐SO3/SWNT composite in aqueous solution was investigated. The addition of MV2+ enhanced the fluorescence intensity of the mPPE‐SO3/SWNT composite by inducing a conformational change of the polymer from a helical to a random‐coil structure. The water‐soluble mPPE‐SO3/SWNT composite enabled highly sensitive fluorescence detection of MV2+ in aqueous solutions with no precipitation resulting from reaggregation of the SWNTs. This mPPE‐SO3/SWNT composite sensor system is therefore an effective turn‐on chemical sensor for MV2+. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43301.  相似文献   

11.
Multi‐walled carbon nanotube (MWCNT) was non‐covalently functionalized with room‐temperature ionic liquid (IL), 1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate and blended with epoxy pre‐polymer (ER) with the assistance of ultrasonication in the presence of acetone as a diluting medium. The ability of IL in improving the dispersion of MWCNT in epoxy pre‐polymer was evidenced by transmission optical microscopy. The corresponding epoxy/MWCNT networks cured with anhydride displayed an increase of the electrical conductivity of around three orders of magnitude with the addition of IL in a proportion of MWCNT/IL = 1:5 mass ratio. The effect of IL on dynamic mechanical properties and thermal conductivity was also evaluated. The improved thermal and electrical properties was attributed to the better dispersion of MWCNT within the epoxy matrix by IL, evidenced by transmission electron microscopy of the ER/MWCNT networks cured with anhydride. Raman spectroscopy was also used to confirm the interaction between MWCNT and IL. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43976.  相似文献   

12.
In this work, approach to use of noncovalently modified carbon nanotubes is given for preparation of functional hybrid polymeric composite materials (HPCM) based on epoxy resin. Conductive glass‐fiber plastics with resistivity in transverse and lengthwise direction 9.0·× 102 and 30–50 Ohm cm, respectively, were obtained. The tetrafluoroethylene telomer and fluorocontaining organosilicon copolymer with amino groups were used as modifiers for carbon nanotubes. Thermal, electrical, and mechanical properties of the obtained materials were studied. The mechanism of the effect of noncovalent modification of carbon nanotubes on functional properties of HPCM was discussed. It was found, that type of modifier significantly affects the level of functional properties. The use of fluorocontaining organosilicon copolymer is more optimal in comparison with tetrafluoroethylene telomer. Thus, HPCM with carbon‐fiber filler and this modifier has higher electrical conductivity and lightning strike resistance in comparison with nonmodified HPCM. This approach is promising to impart antistatic properties for glass‐fiber plastics and increase lightning resistance of carbon‐fiber plastics. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46108.  相似文献   

13.
In this study, reduced graphene oxide (RGO) has been introduced as conductive filler within polyaniline (PAni) nanotubes (PAniNTs) by in situ chemical reduction method to enhance the properties of PAniNTs. The effect of varied concentration of in situ reduced GO on the structural, thermal, electrical, and dielectric properties of RGO–PAniNTs nanocomposites have been investigated by high resolution transmission electron microscope, X‐ray diffraction, Fourier transform infrared, thermogravimetric analysis, IV characteristics, and impedance analyzer. The enhanced thermal stability of the nanocomposites has been analyzed from the derivative thermogravimetric curves in terms of onset and rapid decomposition temperature. The transport mechanisms have been studied by fitting the nonlinear IV characteristics to the Kaiser model. The dielectric relaxation phenomena have been investigated by permittivity and modulus formalisms. Characteristic relaxation frequency of RGO–PAniNTs nanocomposites shifts toward higher frequency with increasing RGO concentration indicating a distribution in conductivity relaxation. The distribution of relaxation time has been studied by fitting the imaginary modulus spectra of the nanocomposites to Bergman modified KWW function. The ac conductivity spectra are fitted to the Jonscher's power law equation and enhanced conductivity value of 1.26 × 10−3 S cm−1 is obtained for 40 wt % of RGO compared to 1.22 × 10−4 S cm−1 for PAniNTs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45883.  相似文献   

14.
In this work, a modified parallel-disks configuration on a strain-controlled ARES rheometer (TA Instrument) was used to study the evolution of the electrical resistivity at rest and during oscillatory shearing of a co-continuous immiscible polymer blend morphology based on polypropylene and /polymethyl(methacrylate) (PP/PMMA) in which various amounts (0–3 wt%) of multiwall carbon nanotubes (MWCNT) were added. The co-continuity of both PP and PMMA phases allowed the buildup of a conductive network due to the preferential localization of the conductive MWCNT at the interface between PP and PMMA. Under a stepwise increase of the oscillatory strain amplitude below a critical value (γc = 6.3%), a significant decrease in the electrical resistivity was observed for MWCNT concentrations above the percolation threshold (0.3 wt%) due to the conductive paths induced by both thermal (Brownian) motion and oscillatory shearing. However, for deformation amplitudes higher than γc, the resistivity increased due to the destruction of the MWCNT paths induced by the large deformation imposed on the PP/PMMA interface. These observations were also confirmed by the evolution of the storage modulus (G′) which remained constant for γc < 6.3% (linear viscoelastic regime), while the values decreased above γc due to the destruction of the system's morphology.  相似文献   

15.
In this work, the electrical surface conductivity enhancement of injection‐molded multiwalled carbon nanotube (MWCNT)/poly(methyl methacrylate) (PMMA) nanocomposite by using CO2 laser processing was studied. Variable input factors are considered as MWCNT concentration (in three levels 0.5, 1, and 1.5 wt %), the laser feed angle with the flow direction (in five levels 0°, 30°, 45°, 75°, and 90°), and the cavity machining method that were produced by electrodischarge machining and computer numerical control milling with finishing process. The studies show that the irradiation of laser and utilization of covering gas could enhance the CNT–CNT contacts and the surface electrical conductivity. The morphology of laser‐irradiated surface by using scanning electron microscope certified that the conductive network generated from CNT–CNT contacts can transfer the electrical current. The findings clearly show that the laser feed angle with the flow direction influenced the electrical conductivity. The maximum conductivity (~ 5.310 × 10?4 S) was observed at 75°. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42671.  相似文献   

16.
Semi-biodegradable polypropylene (PP)/poly(lactic acid) (PLA) (50:50 vol%) blend loaded with 0.6 vol% of pristine carbon nanotube (CNT) were prepared by melt compounding the components using different sequential mixing strategies: (i) all components together (PP/PLA/CNT); (ii) PP first mixed with CNT (PP@CNT/EVA) and (iii) EVA first mixed with CNT (EVA@CNT/PP). The composites presented co-continuous structure and the CNT selectively localized inside the PP phase or at the interface, regardless the order of the CNT addition into the mixing. These features were confirmed by selective extraction experiments and morphological studies: optical, scanning electron, and transmission electron microscopy. However, the preferential localization at the interface was predicted from wetting coefficient, determined from interfacial energy. Higher electrical conductivity values were achieved by using the one-step mixing approach, were all components were mixed together, whose value of around 10−4 S/m was achieved by adding 0.6 vol% of CNT to the blend. The compatibilization with polypropylene-g-maleic anhydride increased the melt viscosity of the blend and composite but did not affect the conductivity or the tensile properties of the CNT-based composite.  相似文献   

17.
In this article, the effect of Multi‐walled carbon nanotubes (MWCNTs) on the electrical conductivity and mechanical properties of polycarbonate (PC) toughened with cross‐linked ethylene‐propylene copolymer (EPC) was investigated. The solubility parameters of the PC and EPC were calculated using Hoy methods to clarify the miscibility of the polymer blends. It could be concluded that in the cooled state, the blends form a heterogeneous structure with two separate phases. The tensile, flexural, impact toughness properties of the PC/EPC blend and PC/EPC/MWCNT nanocomposites were carried out to illuminate the optimum concentration of polymer blends and MWCNTs. The 335% increment for the impact strength results appeared with combination of 10% EPC in the PC matrix. The flexural modulus and strength of PC/EPC blend increased by 75.1% and 59.1%, respectively. The Nielsen model was performed to fit the best curve of theoretical simulation to experimental results for elastomeric dispersed in the plastic matrix. Halpin‐Tsai model was applied to estimate the stiffness of nanocomposites blends with different volume fraction and aspect ratio of MWCNTs in the PC/EPC blends. Finally, in the presence of MWCNTs, all nanocomposite samples were semi‐conducting and the percolation threshold of the PC/EPC (10%) blends was between 0.5% and 1.0% MWCNTs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44661.  相似文献   

18.
Nanotubes (NTs), especially carbon nanotubes (CNTs), have attracted much attention in recent years because of their large specific surface area, and their outstanding mechanical, thermal, and electrical properties. In this review we emphasize the development of fascinating properties of polymeric carbohydrate/CNT composites, particularly in terms of their mechanical and conductivity properties and potential applications. Many methods used to modify CNTs during preparation of polymeric carbohydrate/CNT composites are presented. Moreover, we also discuss the enhanced mechanical and electrical effectiveness when hybrid CNTs or halloysite nanotubes were incorporated into different carbohydrate polymer matrices. Finally, we give a future outlook for the development of polymeric carbohydrate/CNT composites as potential alternative materials for various applications including sensors, electroactive paper, electrodes, sorbents for environmental remediation, packaging film, specialty textile, and biomedical devices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40359.  相似文献   

19.
Poly(methyl methacrylate) (PMMA) composites containing raw or purified single‐walled carbon nanotubes (SWCNTs) are prepared by in situ polymerization and solution processing. The SWCNTs are purified by centrifugation in a Pluronic surfactant, which consists of polyethyleneoxide and polypropyleneoxide blocks. Both the effects of SWCNT purity and non‐covalent functionalization with Pluronic are evaluated. Electrical conductivity of PMMA increases by 7 orders of magnitude upon the integration of raw or purified SWCNTs. The best electrical properties are measured for composites made of purified SWCNTs and prepared by in situ polymerization. Strains at fracture of the SWCNT/PMMA composites are nearly identical to those of the neat matrix. A certain decrease in the work to fracture is measured, particularly for composites containing purified SWCNTs (?31.6%). Fractography and Raman maps indicate that SWCNT dispersion in the PMMA matrix improves upon the direct addition of Pluronic, while dispersion becomes more difficult in the case of purified SWCNTs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41547.  相似文献   

20.
In this article, we present the synthesis and characterization of a new thiophenic copolymer bearing the C60 fullerene directly linked to the end of a hexamethylenic side chain. This copolymer was prepared with good yield using a simple and straightforward post‐polymerization functionalization procedure applied on a soluble regioregular polymeric precursor obtained by regiospecific organometallic coupling. Copolymer structural and photophysical properties were investigated by gel permeation chromatography, thermal analysis (DSC and TGA), NMR, IR, UV–Vis, and atomic force spectroscopy. The double‐cable copolymer possesses good solubility in common organic solvents, high filmability, thermal stability, and low segmental aggregation tendency. It was tested as a photoactive layer in a polymeric solar cell showing a power conversion efficiency under 100 mW cm?2 AM 1.5 illumination higher than 4%, more than that of the reference cell made with the conventionally used P3HT/PCBM blend. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42121.  相似文献   

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