Water-dispersible nanocomposites of polyaniline and montmorillonite

Biswas, Mukul; Ray, Suprakas Sinha

doi:10.1002/1097-4628(20000923)77:13<2948::aid-app18>3.0.co;2-f

Cited by 66 publications

(62 citation statements)

References 20 publications

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“…Three layered silicates were used, i.e. the native sodium montmorillonite (MMT-Na) and two organo-modified montmorillonites MMT-Alk and MMT-(OH) 2 , that result from the exchange of the Na + cations by dimethyl 2-ethylhexyl (hydrogenated tallow alkyl) ammonium and methyl (hydrogenated tallow alkyl) bis(2-hydroxyethyl) ammonium cations, respectively. Polymerization was conducted in bulk at 100°C in the presence of 15-33 wt% of (organo)-clay depending on the filler and its dispersion in liquid -caprolactone.…”

Section: Preparation Of Pcl/clay Masterbatchesmentioning

confidence: 99%

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Polymer/layered silicate nanocomposites by combined intercalative polymerization and melt intercalation: a masterbatch process

Lepoittevin

Pantoustier

Devalckenaere

et al. 2003

Polymer

163

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Poly(ε-caprolactone) (PCL) and poly(vinyl chloride) (PVC) layered silicate nanocomposites were prepared by combination of intercalative polymerization and melt intercalation. In a first step, high clay content PCL nanocomposites were prepared by in situ polymerization of -caprolactone intercalated between selected organo-modified silicate layers. The polymerization was catalyzed with dibutyltin dimethoxide in the presence of montmorillonites, the surface of which were previously exchanged with (functionalized) long alkyl chains ammonium cations. Then, these highly filled PCL nanocomposites were added as masterbatches in commercial PCL and PVC by melt blending. The intercalation of PCL chains within the silicate layers by in situ polymerization proved to be very efficient, leading to the formation of intercalated and/or exfoliated structures depending on the organo-clay. These masterbatches were readily dispersed into the molten PCL and PVC matrices yielding intercalated/exfoliated layered silicate nanocomposites which could not be obtained by melt blending the matrix directly with the same organo-modified clays. The formation of nanocomposites was assessed both by X-ray diffraction and transmission electronic microscopy. Interestingly, this so-called 'masterbatch' two-step process allowed for preparing PCL nanocomposites even with non-modified natural clay, i.e. sodium montmorillonite, which showed a material stiffness much higher than the corresponding microcomposites recovered by direct melt intercalation. The thermal stability of PCL nanocomposites as a function of clay content was investigated by thermogravimetry (TGA).

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Section: Preparation Of Pcl/clay Masterbatchesmentioning

confidence: 99%

“…Polymer/layered silicate nanocomposites are a new class of materials with enhanced properties compared to parent conventional (micro)composites and unfilled polymers [1][2]. As a rule, the homogeneous dispersion of 3-5 wt% of thin clay layers (ca.…”

Section: Introductionmentioning

confidence: 99%

Polymer/layered silicate nanocomposites by combined intercalative polymerization and melt intercalation: a masterbatch process

Lepoittevin

Pantoustier

Devalckenaere

et al. 2003

Polymer

163

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“…After the observation of PANI intercalation into Cu 21 exchanged silicates by Cloos et al in 1979, 19 a number of studies on the preparation, properties and applications of PANI/layered silicate nanocomposites were carried out. [10][11][12][13][14][20][21][22][23][24][25][26][27][28] Most recently, Yang and Chen reported the synthesis of PANI/ organically modified clay nanocomposites and found that more PANI chains are formed between interlayer spacings of the modified clay, especially for HOOC(CH 2 ) 11 NH 3 1 modified clay because the acidic HOOC(CH 2 ) 11 NH 3 1 ions residing between interlayer spacings provide a stronger driving force for the intercalation of aniline monomer. 29 Yeh et al reported that regardless of clay content, the synthesis of PANI/clay nanocomposites with exfoliated silicate layers of clay was realized and they investigated the effect of such nanocomposites on the corrosion protection of cold rolled steel (CRS) when compared with that of an emeraldine base of PANI using a series of electrochemical measurements of corrosion potential and polarization resistance.…”

Section: Introductionmentioning

confidence: 99%

Structural changes of polyaniline/montmorillonite nanocomposites and their effects on physical properties

et al. 2003

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Polyaniline/montmorillonite (MMT) nanocomposites containing different PANI contents were prepared by the intercalation of aniline monomer into pristine MMT followed by the subsequent oxidative polymerization of the aniline in the interlayer spacings. The polyaniline/MMT nanocomposite structure intercalated with polyaniline (PANI) was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). From the full-width at half-maximum (FWHM) of the (001) reflection peaks in the XRD patterns, the PANI/ MMT nanocomposite containing 12.3 wt% PANI (PMN12) was found to be in the most disordered state. The physical interaction between the intercalated PANI and the basal surfaces of MMT was monitored by FT-IR. The room-temperature conductivity (s RT ) varied from 9.1 6 10 29 to 1.5 6 10 0 S cm 21 depending on the PANI content in the nanocomposites. The temperature dependence of dc conductivity (s dc (T)) of all the samples follows the quasi-1D variable range hopping (quasi-1D VRH) model (i.e., s dc (T) 3 exp [2(T 0 /T) 1/2 ]). The charge transport behavior of this system was interpreted from the slopes (T 0 ) of the s dc curves and the highest T 0 value was found for the PANI/MMT nanocomposite with 12.3 wt% PANI (PMN12). The FT-IR, s dc (T) and s RT results for the nanocomposites with varying content of PANI are consistently related to the structure of the PANI/MMT nanocomposites discussed in the XRD analysis. The structural argument was further supported by scanning electron microscopy (SEM) of all the samples. Thermogravimetric analysis (TGA) showed improved thermal stability for the intercalated nanocomposites in comparison with the pure PANI and a simple PANI/MMT mixture.

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“…1,9 In contrast, PANI-MMT and PPY-MMT composite dispersions showed formation of spherical particles. Magnified TEM images of a narrow section of PANI-MMT and PPY-MMT composite dispersions were taken (Figures 2a and 2b respectively) to understand how the spherical polymers were accommodated in the MMT lamellae.…”

Section: Transmission Electron Micrographic Characteristicsmentioning

confidence: 91%

“…It was also observed by these workers that the melt interaction or solvent polymerization of NVC in presence of MMT involved intercalation of the polymer in the MMT lamellae which was confirmed by the manifestation of a d-spacing of 14.04 A in the XRD scan of the PNVC (polyN-vinylcarbazole)-MMT composite. Subsequently, attempts of these authors 9,10 to polymerize ANI or PY under these conditions in presence of externally added oxidants (FeCl 3 /S 2 O 8 2À ) led to the formation of polyaniline (PANI) or polypyrrole (PPY) which were not intercalated in the MMT lamellae and existed only as surface-adsorbed polymers. On the other hand, Mehrotra and Giannelis 11,12 prepared highly oriented multi-layered PANI films by intercalative polymerization of ANI in a synthetic mica type silicate Cu fluorohectorite from liquid phase (or vapour phase).…”

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confidence: 99%

High Yield Polymerisation of Aniline and Pyrrole in Presence of Montmorillonite Clay and Formation of Nanocomposites Thereof

Ballav

Biswas

2004

Polym J

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KEY WORDSIntercalative Polymerization / Nanocomposite / Thermogravimetric Stability / Conductivity / Sorbed Cation / Considerable research attention was paid during the last decade on synthesis and evaluation of clay-polymer nanocomposites. Of the various techniques explored for such preparations impregnation of monomers followed by polymerization was used for a variety of monomers. Thus monomers like acrylonitrile, styrene, butadine, methylmethacrylate etc were impregnated into clays and were polymerized in presence of free radical initiators.1 Since the adsorption of monomer molecules between the clay lamellae was dependent on the dipole-moment of the monomer molecule, the yields of the physically inserted polymers were found to be low in general. [2][3][4][5][6] In this context we wish to report that we have achieved high yield polymerization of aniline (ANI) and pyrrole (PY) in presence of montmorillonite (MMT) clay without the addition of any extraneously added oxidants like FeCl 3 or (NH 4 ) 2 S 2 O 8 . 7 Earlier, Biswas and SinhaRoy reported 8 that the polymerization of N-vinylcarbazole (NVC) monomer could be induced in presence of MMT in bulk (NVC, MMT, 68 C) and under reflux condition using CHCl 3 solvent without any externally added oxidant. It was also observed by these workers that the melt interaction or solvent polymerization of NVC in presence of MMT involved intercalation of the polymer in the MMT lamellae which was confirmed by the manifestation of a d-spacing of 14.04A in the XRD scan of the PNVC (polyN-vinylcarbazole)-MMT composite. Subsequently, attempts of these authors 9,10 to polymerize ANI or PY under these conditions in presence of externally added oxidants (FeCl 3 /S 2 O 8 2À ) led to the formation of polyaniline (PANI) or polypyrrole (PPY) which were not intercalated in the MMT lamellae and existed only as surface-adsorbed polymers. On the other hand, Mehrotra and Giannelis 11,12 prepared highly oriented multi-layered PANI films by intercalative polymerization of ANI in a synthetic mica type silicate Cu fluorohectorite from liquid phase (or vapour phase). Gallery Cu 2þ ions introduced by an ion-exchange process, served as the oxidation centers for the polymerization of ANI.In this background the results of the present study appear to be particularly significant and provide some useful new information concerning the general field of clay-polymer interaction. The preparation, structural characterization and evaluation of some selective bulk properties of PANI-MMT and PPY-MMT composites are described in this article.

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Water-dispersible nanocomposites of polyaniline and montmorillonite

Cited by 66 publications

References 20 publications

Polymer/layered silicate nanocomposites by combined intercalative polymerization and melt intercalation: a masterbatch process

Polymer/layered silicate nanocomposites by combined intercalative polymerization and melt intercalation: a masterbatch process

Structural changes of polyaniline/montmorillonite nanocomposites and their effects on physical properties

High Yield Polymerisation of Aniline and Pyrrole in Presence of Montmorillonite Clay and Formation of Nanocomposites Thereof

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