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1.
Polyaniline (PANI)/multiwalled carbon nanotube (MWNT) composites with a uniform tubular structure were prepared from in situ polymerization by dissolving amino‐functionalized MWNT (a‐MWNT) in aniline monomer. For this the oxidized multiwalled nanotube was functionalized with ethylenediamine, which provided ethylenediamine functional group on the MWNT surface confirmed by Fourier‐transform infrared spectra (FT‐IR). The a‐MWNT was dissolved in aniline monomer, and the in situ polymerization of aniline in the presence of these well dispersed nanotubes yielded a novel tubular composite of carbon nanotube having an ordered uniform encapsulation of doped polyaniline. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that the nanotubes were coated with a PANI layer. The thermal stability and electrical conductivity of the PANI /MWNTs composites were characterized by thermogravimetric analysis (TGA) and conventional four‐probe method respectively. Compared with pure PANI, the electrical conductivity and the decomposition temperature of the MWNTs/PANI composites increased with the enhancement of MWNT content in PANI matrix. POLYM. COMPOS., 34:1119–1125, 2013. © 2013 Society of Plastics Engineers  相似文献   

2.
A novel oligomeric phosphorous–nitrogen‐containing intumescent flame retardant poly (2,6‐diaminopyridine spirocyclic pentaerythritol bisphosphonate) (PDSPB) is synthesized, and subsequently multiwalled carbon nanotube (MWNT)‐grafted oligomeric intumescent flame retardant, MWNT‐g‐PDSPB, is fabricated via chemical grafting reaction and characterized. The grafting reaction was characterized by FTIR, NMR, and XPS. After high‐density PDSPB (88 wt%) were attached to the MWNTs, core‐shell nanostructures with MWNTs as the hard core and PDSPB as the soft shell were formed. The resultant MWNT‐g‐PDSPB was soluble and stable in polar solvents, such as DMF and DMSO. MWNT‐g‐PDSPB has excellent thermal stability and charring ability. The TEM results showed that the functionalized MWNTs could achieve better dispersion in poly(ethylene vinyl acetate) (EVA) matrix. The residue char of MWNT‐g‐PDSPB is as high as 70 wt%, and the grafting of intumescent flame retardant of PDSPB can improve both the dispersion of MWNTs in polymer matrix and flame retardancy of the nanocomposites. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers  相似文献   

3.
Incorporation of carbon nanotubes (CNTs) in conducting polymer can lead to new composites with enhanced electrical and mechanical properties. However, the development of such composites has been hampered by the inability to disperse CNTs in polymer matrix due to the lack of chemical compatibility between polymers and CNTs. Covalent sidewall functionalization of carbon nanotube provides a feasible route to incorporate carbon nanotube in polymer. In this work, 4‐aminobenzene groups were grafted onto the surface of multi‐walled carbon nanotube (MWNT) via C? C covalent bond. Polyaniline (PANI)/MWNT composites were fabricated by electrochemical polymerization of aniline containing well‐dissolved functionalized MWNTs. The obtained composites can be used as catalyst supports for electrooxidation of formic acid. Cyclic voltammogram results show that platinum particles deposited in PANI/MWNT composite films exhibit higher electrocatalytic activity and better long‐term stability towards formic acid oxidation than that deposited in pure PANI films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

4.
Tzong-Ming Wu  Yen-Wen Lin 《Polymer》2006,47(10):3576-3582
This study reports the synthesis of doped polyaniline in its emeraldine salt form (PANI-ES) with carboxylic acid and acylchloride groups contained multi-walled carbon nanotubes (designated as c-MWNTs and a-MWNTs) by in situ polymerization. Both Raman spectra and HRTEM images indicate that carboxylic acid and acylchloride groups formed at both ends and on the sidewalls of the MWNTs. Based on the π-π* electron interaction between aniline monomers and functionalized MWNT and hydrogen bonding interaction between the amino groups of aniline monomers and the carboxylic acid/acylchloride groups of functionalized MWNT, aniline molecules were adsorbed and polymerized on the surface of MWNTs. Structural analysis by FESEM and HRTEM showed that PANI-ES/c-MWNT and PANI-ES/a-MWNT composites are core (c-MWNT or a-MWNT)- shell (doped-PANI-ES) tubular structures with diameters of several tens to hundreds of nanometers, depending on the PANI content. The conductivities of 0.5 wt% functionalized MWNT containing PANI-ES/c-MWNT and PANI-ES/a-MWNT composites are 60-70% higher than that of PANI without MWNT.  相似文献   

5.
High electrochemical active free‐standing multiwalled carbon nanotube (MWNT) films have been synthesized from aniline oligomer functionalized MWNTs (MWNT‐AO), by using filtration of the acidic phosphate ester (APE) doped MWNT‐AO dispersions. The homogeneously distributed MWNTs endowed APE/MWNT films automatically releasing from the filter membrane. The sheet resistivity of MWNT‐AO (850 Ω sq?1) showed a lower value than that of carboxyl MWNTs (1273 Ω sq?1), due to the doping effect of MWNT on aniline oligomer, confirmed by the N1s X‐ray photoelectron spectrum. However, it showed a higher sheet resistivity value of 1526 Ω sq?1 after further doped by APE, because of the presence of unreacted dopant. After removing the residual insulating dopant by the vacuum filtration, the resultant APE/MWNT films showed the sheet resistivity value as low as 131 Ω sq?1. Thermogravimetric analysis showed that the MWNT loading in the film can be over than 77%, which showed the specific capacitance as high as 249 F g?1. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40259.  相似文献   

6.
Ethylenediamine (EDA) covalently functionalized graphene sheets (GS‐EDA) and acidized carbon nanotubes (MWNTs‐COOH) were first prepared, followed by synthesizing l ‐aspartic acid functionalized GS‐EDA/MWNTs‐COOH (LGC) hybrid nanomaterials by using l ‐aspartic acid as a bridging agent. Then nanocomposites of high density polyethylene‐g ‐maleic anhydride (HDPE‐g ‐MAH) synergistic strengthening–toughening using LGC hybrids were prepared via melt compounding method. The surface structure of filler was characterized by using infrared (FTIR) and Raman spectrum. The synergistic strengthening–toughening effects of LGC hybrids on the HDPE‐g ‐MAH were investigated by scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), tensile, and impact tests. FTIR showed that EDA has been grafted on the graphene sheets, and ? COOH group has been introduced into MWNTs. The l ‐aspartic acid connected GS‐EDA and MWNTs‐COOH through chemical bonds. SEM observations showed that LGC hybrids were homogeneously dispersed in HDPE‐g ‐MAH nanocomposites. Tensile and impact tests indicated that the mechanical properties of nanocomposites were improved obviously when LGC hybrid nanomaterials were incorporated simultaneously. DMA analysis indicated that the storage modulus of composites was higher than that of pure HDPE‐g ‐MAH matrix. TGA results revealed that the maximum decomposition temperature of HDPE‐g ‐MAH composites containing 0.75 wt % of LGC showed 11.5 °C higher than that of HDPE‐g ‐MAH matrix. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45055.  相似文献   

7.
Thermally conductive polystyrene (PS)/multi‐walled carbon nanotubes (MWNTs) nanocomposites was prepared through a simple solution‐evaporation method assisted by ultrasonic irradiation. To enhance the dispersion of MWNTs in PS, MWNTs were chemically functionalized with poly(styrene‐co‐maleic anhydride) (SMA) (MWNT‐g‐SMA), which had benzene group and exhibited strong affinity with PS. The thermal conductive properties of PS increased and the mechanical properties decreased in presence of MWNTs, while by addition of MWNT‐g‐SMA, the properties of the composites can be improved to some extent. The thermal conductivity can reach 0.89 W/m K for the composite with 33.3 vol % MWNT‐g‐SMA, which was four times higher than that of neat PS. A linear increase of the thermal conductivity was observed with increasing MWNTs‐g‐SMA content, and the Maxwell–Eucken model and the Agari model were used for theoretical evaluation. Compared with MWNT‐OH, MWNT‐g‐SMA with larger diameter exhibited diffused boundary with the PS matrix, resulting from the strong interfacial bonding of the two phases. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

8.
This study systematically investigates the polymer–carbon nanotube (CNT) interaction when the interphase is tailored. Maleic anhydride‐grafted‐polypropylene (MA‐g‐PP) or polypropylene (PP) was noncovalently coated onto acid functionalized multiwall nanotube (f‐MWNT) through solution mixing. These coated f‐MWNTs were melt microcompounded with neat PP to form PP/f‐MWNT nanocomposites. The effects of functional groups and the thin layer of solution processed polymers, namely, MA‐g‐PP or PP, at the PP/f‐MWNT interface on crystallization and on melting behavior of matrix PP were investigated. The results were compared with a pristine MWNT (p‐MWNT) incorporated system. It was shown that PP coated CNTs can serve as a strong nucleating agent for templated polymer crystal growth. Unlike other PP nanocomposites in the literature, a relatively high shift of 7°C in melting peak maximum (Tp), along with a sharp melt endotherm was achieved with the addition of 0.3 wt% f‐MWNT via PP/f‐MWNT master batch. This indicates refinement of matrix PP crystalline region due to the tailored f‐MWNT surface chemistry. With a designed self‐seeding and templated crystal growth approach, columnar crystalline interphases were found surrounding MWNT which melted at 10.5°C higher temperature than neat PP crystallized without undergoing the same heat treatment protocol. POLYM. ENG. SCI., 59:1570–1584 2019. © 2019 Society of Plastics Engineers  相似文献   

9.
A novel cyclic initiator was synthesized from dibutyl tin(IV) oxide and hydroxyl‐functionalized multiwalled carbon nanotubes (MWNTs) and was used to initiate the ring‐opening polymerization of cyclic butylene terephthalate oligomers to prepare poly(butylene terephthalate) (PBT)/MWNT nanocomposites. The results of Fourier transform infrared and NMR spectroscopy confirmed that a graft structure of PBT on the MWNTs was formed during the in situ polymerization; this structure acted as an in situ compatibilizer in the nanocomposites. The PBT covalently attached to the MWNT surface enhanced the interface adhesion between the MWNTs and PBT matrix and, thus, improved the compatibility. The morphologies of the nanocomposites were observed by field emission scanning electron microscopy and transmission electron microscopy, which showed that the nanotubes were homogeneously dispersed in the PBT matrix when the MWNT content was lower than 0.75 wt %. Differential scanning calorimetry and thermogravimetric analysis were used to investigate the thermal properties of the nanocomposites. The results indicate that the MWNTs acted as nucleation sites in the matrix, and the efficiency of nucleation was closely related to the dispersion of the MWNTs in the matrix. Additionally, the thermal stability of PBT was improved by the addition of the MWNTs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

10.
BACKGROUND: The technological development of poly(ε‐caprolactone) (PCL) is limited by its short useful lifespan, low modulus and high crystallinity. There are a few papers dealing with the crystallization behavior of carbon nanotube‐reinforced PCL composites. However, little work has been done on the crystallization kinetics of melt‐compounded PCL/multiwalled carbon nanotube (MWNT) nanocomposites. In this study, PCL/MWNT nanocomposites were successfully prepared by a simple melt‐compounding method, and their morphology and mechanical properties as well as their crystallization kinetics were studied. RESULTS: The MWNTs were observed to be homogeneously dispersed throughout the PCL matrix. The incorporation of a very small quantity of MWNTs significantly improved the storage modulus and loss modulus of the PCL/MWNT nanocomposites. The nonisothermal crystallization behavior of the PCL/MWNT nanocomposites exhibits strong dependencies of the degree of crystallinity (Xc), peak crystallization temperature (Tp), half‐time of crystallization (t1/2) and Avrami exponent (n) on the MWNT content and cooling rate. The MWNTs in the PCL/MWNT nanocomposites exhibit a higher nucleation activity. The crystallization activation energy (Ea) calculated with the Kissinger model is higher when a small amount of MWNTs is added, then gradually decreases; all the Ea values are higher than that of pure PCL. CONCLUSION: This paper reports for the first time the preparation of high‐performance biopolymer PCL/MWNT nanocomposites prepared by a simple melt‐compounding method. The results show that the PCL/MWNT nanocomposites can broaden the applications of PCL. Copyright © 2008 Society of Chemical Industry  相似文献   

11.
An uniformly distributed film consisting of polyaniline (PANI) nanoparticles and carboxylic acid functionalized multiwalled carbon nanotubes (MWNTs‐COOH) was successfully assembled on ITO plates from a layer‐by‐layer (LBL) method by using electrostatic interactions as the main driving force. The good conjugation between PANI nanoparticles and MWNTs‐COOH resulted in significant electrochemical performance variation of the obtained films. In addition, the assembled MWNT‐COOH/PANI/ITO showed synergistic effect to the electrochemical oxidation of nifedipine (NIF) when used as a sensor. Compared with bare ITO, the oxidation potential of NIF can be decreased about 170 mV on MWNT‐COOH/PANI/ITO, and the lower detection limit of NIF was as low as 1.0 × 10?6 mol/L. In addition, the assembled electrode gave no responses to interferences such as glucose, urea, ascorbic acid, and trisodium citrate, which showed high selectivity for recognition and quantification of NIF. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43452.  相似文献   

12.
BACKGROUND: Recently, much work has focused on the efficient dispersion of carbon nanotubes (CNTs) throughout a polymer matrix for mechanical and/or electrical matrices. However, CNTs used as enhancement inclusions in a high‐performance polymer matrix, especially in poly(aryl ether ketone) (PAEK), have rarely been reported. Therefore, multi‐walled carbon nanotube (MWNT)‐modified PAEK nanocomposites were synthesized by in situ polymerization of monomers of interest in the presence of pre‐treated MWNTs. RESULTS: This process enabled a uniform dispersion of MWNT bundles in the polymer matrix. The resultant MWNT/PAEK nanocomposite films were optically transparent with significant mechanical enhancement at a very low MWNT loading (0.5 wt%). CONCLUSION: These MWNT/polymer nanocomposites are potentially useful in a variety of aerospace and terrestrial applications, due to the combination of excellent properties of MWNTs with PAEK. Copyright © 2009 Society of Chemical Industry  相似文献   

13.
BACKGROUND: The development of carbon nanotube‐reinforced composites has been impeded by the difficult dispersion of the nanotubes in polymers and the weak interaction between the nanofiller and matrices. Efficient dispersion of carbon nanotubes is essential for the formation of a functional nanotube network in a composite matrix. RESULTS: Multiwalled carbon nanotubes (MWNTs) were incorporated into a polyimide matrix to produce MWNT/polyimide nanocomposites. To disperse well the MWNTs in the matrix and thus improve the interfacial adhesion between the nanotubes and the polymer, ‘branches’ were grafted onto the surface of the nanotubes by reacting octadecyl isocyanate with carboxylated MWNTs. The functionalized MWNTs were suspended in a precursor solution, and the dispersion was cast, followed by drying and imidization to obtain MWNT/polyimide nanocomposites. CONCLUSION: The functionalized MWNTs appear as a homogeneous dispersion in the polymer matrix. The thermal stability and the mechanical properties are greatly improved, which is attributed to the strong interactions between the functionalized MWNTs and the polyimide matrix. Copyright © 2009 Society of Chemical Industry  相似文献   

14.
s‐Triazine‐based hyperbranched polyurethanes (HBPUs) with different hard segments were synthesized by A2 + B3 approach. Various kinds of multiwalled carbon nanotube (MWNT) nanocomposites with HBPU were prepared to investigate an impact of hyperbranched polymer on dispersion of MWNTs in the polymer matrix and the resulting properties of nanocomposites. Synthesized HBPUs were characterized using FTIR and NMR measurements. The highly branched structures were found very effective in enhancing the pristine MWNT dispersion in the polymer matrix. As a result, the MWNT‐reinforced HBPU nanocomposites showed a steep increase in the yield stress and modulus and enhanced shape memory effect with an increase of hard segment and MWNT loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

15.
The effect of the polymeric crosslink density on the thermal conductivity of an epoxy nanocomposite was investigated by adding two different diamine‐functionalized multiwalled carbon nanotubes (diamine‐MWNTs) to the epoxy resin as co‐curing agents and conducting fillers. Tetramethylenediamine (TMDA)‐MWNTs resulted in an epoxy nanocomposite with a higher crosslink density than octamethylenediamine (OMDA)‐MWNTs. Interestingly, epoxy/TMDA‐MWNT nanocomposites under 1.5 wt % nanotube concentration, showed a higher thermal conductivity than an epoxy/OMDA‐MWNT nanocomposite with the same concentration of nanotubes. In contrast, for higher diamine‐MWNT concentrations (over 2.0 wt %), the thermal conductivity of the epoxy/OMDA‐MWNT nanocomposite was higher than that with TMDA‐MWNTs. We observed that for low MWNT concentrations, where a percolating network was not formed, a high crosslink density enhanced the thermal conductivity via phonon transport. However, for high MWNT concentrations, a high crosslink density hinders the formation of a percolating network and lowers the thermal conductivity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44253.  相似文献   

16.
This article describes an ultrasonically assisted in situ interfacial dynamic inverse emulsion polymerization process of aniline in the presence of multiwalled carbon nanotubes (MWNT) in chloroform. During polymerization, MWNT are coated with polyaniline (PANI) forming a core‐shell structure of nanowires, as evidenced by cryogenic transmission electron microscopy. Thermogravimetric analysis curves and conversion measurements provided important knowledge regarding the unique polymerization method. Scanning electron microscopy images and surface resistivity imply that PANI/MWNTs are characterized by a structural synergistic effect. The PANI coating of MWNT leads to a remarkable improvement in separation and dispersion of MWNT in chloroform, which otherwise would rapidly coagulate and settle. The presented interfacial dynamic polymerization process is very fast, reaching 82% conversion within 5 min of sonication and produces stable clear dispersions of doped PANI in chloroform. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

17.
Multi‐walled carbon nanotube (MWNT)‐reinforced polyimide nanocomposites were synthesized by in situ polymerization of monomers in the presence of acylated MWNTs. The acyl groups associated with the MWNTs participated in the reaction through the formation of amide bonds. This process enabled uniform dispersion of MWNT bundles in the polymer matrix. The resultant MWNT–polyimide nanocomposite films were optically transparent with significant mechanical enhancement at a very low loading (0.5 wt%). Evidence has been obtained for improved interactions between the nanotubes and the matrix polymer. Copyright © 2006 Society of Chemical Industry  相似文献   

18.
Multiwalled carbon nanotube/polycaprolactone nanocomposites (MWNT/PCL) were prepared by in situ polymerization, whereby as‐received MWNTs (P‐MWNTs) and purified MWNTs (A‐MWNTs) were used as reinforcing materials. The A‐MWNTs were purified by nitric acid treatment, which introduced the carboxyl groups (COOH) on the MWNT. The micrographs of the fractured surfaces of the nanocomposites showed that the A‐MWNTs in A‐MWNT/PCL were better dispersed than P‐MWNTs in PCL matrix (P‐MWNT/PCL). Percolation thresholds of the P‐MWNT/PCL and A‐MWNT/PCL, which were studied by rheological properties, were found at ~2 wt % of the MWNT. The conductivity of the P‐MWNT/PCL was between 10?1 and 10?2 S/cm by loading of 2 wt % of MWNT although that of the A‐MWNT/PCL reached ~10?2 S/cm by loading of 7 wt % of MWNT. The conductivity of the P‐MWNT/PCL was higher than that of the A‐MWNT/PCL at the entire range of the studied MWNT loading, which might be due to the destruction of π‐network of the MWNT by acid treatment, although the A‐MWNT/PCL was better dispersed than the P‐MWNT/PCL. The amount of the MWNT at which the conductivity of the nanocomposite started to increase was strongly correlated with the percolation threshold. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1957–1963, 2007  相似文献   

19.
Polyimide/multi‐walled carbon nanotube (PI‐MWNT) nanocomposites were fabricated by an in situ polymerization process. Chemical compatibility between the PI matrix and MWNTs is achieved by pretreatment of the carbon nanotubes in a mixture of sulfuric acid and nitric acid. The dispersion of MWNTs in the PI matrix was found to be enhanced significantly after acid modification. The glass transition (Tg) and decomposition (Td) temperature of PI‐MWNT nanocomposites were improved as the MWNT content increased from 0.5 to 15 wt%. The storage modulus of the PI/MWNT nanocomposites is nine times higher than that of pristine PI at room temperature. The tensile strength of PI doubles when 7 wt% MWNTs is added. The dielectric constant of the PI‐MWNT nanocomposites increased from 3.5 to 80 (1 kHz) as the MWNT content increased to 15 wt%. The present study demonstrates that enhanced mechanical properties can be obtained through a simple in‐situ polymerization process. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers  相似文献   

20.
The paper presents the electrostatic charge dissipative performance of conducting polymer nanocomposite impregnated fabric based on polyaniline (PANI) and zinc oxide nanoparticles (ZnO NPs). Conducting polymer nanocomposites (PANI‐ZnO NPs) were synthesized by in situ chemical oxidative polymerization of aniline by using sodium dodecyl sulfate as surfactant and HCl as dopant. Coating of PANI‐ZnO nanocomposites on the cotton fabric was carried out during polymerization. The interaction of ZnO NPs with the PANI matrix was determined by Fourier transform infrared spectra (FTIR), TGA, XRD, scanning electron Microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and conductivity measurements. The conductivity of PANI‐ZnO NP coated fabric was found to be in the range 10?3 ? 10?6 S cm?1 depending on the loading concentration of ZnO NPs in the polymer matrix. TEM and HRTEM images showed that the PANI‐ZnO nanocomposites had an average diameter of 25–30 nm and were nicely dispersed in the polymer matrix. Antistatic performance of the nanocomposite impregnated fabric was investigated by static decay meter and John Chubb instrument. The static decay time of the film was in the range 0.5 ? 3.4 s on recording the decay time from 5000 V to 500 V. This indicated that the nanocomposite based on PANI‐ZnO nanocomposites has great potential to be used as an effective antistatic material. © 2015 Society of Chemical Industry  相似文献   

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