Synthesis and characterization of polypyrrole/graphite oxide composite by in situ emulsion polymerization

This work demonstrates a feasible route to synthesize the layered polypyrrole/graphite oxide (PPy/GO) composite by in situ emulsion polymerization in the presence of cationic surfactant cetyltrimethylammonium bromide (CTAB) as emulsifier. AFM and XRD results reveal that the GO can be delaminated into nanosheets and well dispersed in aqueous solution in the presence of CTAB. The PPy nanowires are formed due to the presence of the lamellar mesostructured (CTA)₂S₂O₈ as a template. The results of the PPy/GO composite indicate the PPy insert successfully into GO interlayers, and the nanofiber‐like PPy are deposited onto the GO surface. Owing to π–π electron stacking effect between the pyrrole ring of PPy and the unoxided domain of GO sheets, the electrical conductivity of PPy/GO composite (5 S/cm) significantly improves in comparison with pure PPy nanowires (0.94 S/cm) and pristine GO (1 × 10^?6 S/cm). © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1329–1335, 2010     

Synthesis of conducting polypyrrole by radiolysis polymerization method

Conducting polypyrrole (PPy) has been synthesized by the in situ gamma radiation‐induced chemical oxidative polymerization method. This method takes advantages of the specialties of radiation‐induction, and a highly uniform polymer morphology was obtained. The resultant nanosize polypyrrole particles were characterized by Elemental Analysis, Fourier transform infrared (FT‐IR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and X‐ray Diffraction (XRD). Measurements of polymer particle sizes were obtained at <500 nm. A standard four‐point probe revealed that the chemical synthesis of PPy has a good electrical property. Also thermal stability, checked by Thermal Gravimetric Analysis in air, was ensured by this novel synthesis. Copyright © 2007 John Wiley & Sons, Ltd.     

In situ synthesis of A3‐type star polymer/clay nanocomposites by atom transfer radical polymerization

A series of A₃‐type star poly(methylmethacrylate)/clay nanocomposites is prepared by in situ atom transfer radical polymerization (ATRP) initiated from organomodified montmorillonite containing quaternary trifunctional ATRP initiator. The first order kinetic plot shows a linear behavior, indicating the controlled character of the polymerization. The resulting nanocomposites are characterized by spectroscopic (XRD), thermal (DSC and TGA), and microscopic (TEM) analyses. The exfoliated nanocomposite has been obtained when polymerization was conducted with 1% of organic clay loading. Thermal analyses show that all nanocomposites have higher glass transition values and thermal stabilities compared to neat polymer. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5257–5262     

Synthesis of polybenzoxazine/clay nanocomposites by in situ thermal ring‐opening polymerization using intercalated monomer

A new class of polybenzoxazine/montmorillonite (PBz/MMT) nanocomposites has been prepared by the in situ polymerization of the typical fluid benzoxazine monomer, 3‐pentyl‐5‐ol‐3,4‐dihydro‐1,3‐benzoxazine, with intercalated benzoxazine MMT clay. A pyridine‐substituted benzoxazine was first synthesized and quaternized by 11‐bromo‐1‐undecanol and then used for ion exchange reaction with sodium ions in MMT to obtain intercalated benzoxazine clay. Finally, this organomodified clay was dispersed in the fluid benzoxazine monomers at different loading degrees to conduct the in situ thermal ring‐opening polymerization. Polymerization through the interlayer galleries of the clay led to the PBz/MMT nanocomposite formation. The morphologies of the nanocomposites were investigated by both X‐ray diffraction and transmission electron microscopic techniques, which suggested the partially exfoliated/intercalated structures in the PBz matrix. Results of thermogravimetric analysis confirmed that the thermal stability and char yield of PBz nanocomposites increased with the increase of clay content. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

In situ polymerization of ethylene using metallocene catalysts: Effect of clay pretreatment on the properties of highly filled polyethylene nanocomposites

Highly filled polyethylene (PE)‐based nanocomposites were obtained by insitu polymerization technique. An organically modified montmorillonite, Cloisite® 15A (C15A), was previously treated with methylaluminoxane (MAO) to form a supported cocatalyst (C15A/MAO) before being contacted with a zirconocene catalyst. The main features of C15A/MAO intermediates were studied by elemental analysis, TGA, TGA‐FTIR, WAXD, and TEM. MAO reacts with the clay, replaces most of the organic surfactant within the clay galleries and destroys the typical crystrallographic order of the nanoclay. The catalytic activity in the presence of C15A/MAO is higher than in ethylene polymerization without any inorganic filler and increases with MAO supportation time. This indicates that part of the polymer chains grows within the clay galleries, separates them, and makes it possible to tune the final morphology of the composites. The polymerization results and the influence of C15A pretreatment and polymerization conditions on thermal and morphological properties of the hybrid PE/C15A nanocomposites are presented. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5390–5403, 2008     

Synthesis and in situ doping of highly conductive polypyrrole nanocomplexes with binary acids

The synthesis of doped polypyrrole (PPy) nanocomplexes and their size, morphology, doping level, and electrical conductivity are discussed. The synthetic route of doped PPy nanocomplexes is presented by means of the chemical oxidative polymerization and in situ doping process in the presence of a binary acid mixture (hydrochloric acid and perchloric acid). The electrical conductivities of the doped PPy nanocomplexes are enhanced from 0.88 to 4.5 S/cm by the optimum molar ratio of HClO₄ and HCl in the binary acid mixture. In addition, the average particle size of the doped PPy nanocomplexes decreases from 280 to 30 nm with a narrow particle size distribution when increasing the proportion of HClO₄ relative to HCl in the binary acid mixture; this result is confirmed by scanning electron microscopy, transmission electron microscopy, and capillary hydrodynamic fractionation instrument analyses. Moreover, at different molar ratios in the binary acid mixture, the zeta‐potential and oxidation level of the doped PPy nanocomplexes have a confirmed association with particle size and electrical properties. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2329–2336     

Facile one‐step synthesis of electromagnetic functionalized polypyrrole/Fe3O4 nanotubes via a self‐assembly process

This article reports a simple self‐assembly process for facile one‐step synthesis of novel electromagnetic functionalized polypyrrole (PPy)/Fe₃O₄ composite nanotubes using p‐toluenesulfonic acid (p‐TSA) as the dopant and FeCl₃ as the oxidant. The key trick of the present method is to use FeCl₃ as the oxidant for both PPy and Fe₃O₄ in the same time to synthesize PPy/Fe₃O₄ composite nanotubes in one‐step. This facile one‐step method is much simpler than the conventional approach using the Fe₃O₄ nanoparticles as the additives. Compared to the similar composites synthesized using the conventional method, the as‐prepared PPy‐p‐TSA/Fe₃O₄ composite nanotubes using the facile one‐step self‐assembly process show much higher room‐temperature conductivity. Moreover, the composite nanotubes display interesting ferromagnetic behavior. The electrical properties of the PPy‐p‐TSA/Fe₃O₄ composite nanotubes are dominated by the amount of FeCl₃ while their magnetic properties are controlled by the amount of FeCl₂. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 320–326, 2010     

Covalently linked nanocomposites of polypyrrole with graphene: Strategic design toward optimized properties

Graphene‐based nanocomposites with conducting polymers have attracted increasing interest due to the enhanced synergistic properties, which can potentiate and broaden applications. In this context, covalent functionalization stands out as a strategic designing tool, which optimizes the interaction between the nanocomposites components. Herein, covalently linked polymeric nanocomposites were obtained between graphene derivatives and polypyrrole (Ppy) under mild routes (i.e., aqueous, room temperature). First, pyrrole was covalently functionalized on graphene oxide (GO) through stable amide bonds and further polymerization with FeCl₃ led to the polymeric nanocomposites. Finally, to improve conductivity, GO was reduced using NaBH₄. Similarly, analogous non‐covalent nanocomposites were obtained for comparison purposes. All samples were thoroughly characterized by thermogravimetric analysis, scanning electron microscopy, and infrared and Raman spectroscopy, confirming the targeted functionalization, polymerization, and reduction processes. Moreover, the covalent link effectively enhances the interaction of the nanocomposite's components as evidenced by its improved electrochemical stability (300 cycles), compared to the non‐covalent composites which loses conductivity in the initial stages. Indeed, Ppy is known for its low stability, limiting its applications. Overall, the results herein evidence that covalently linked nanocomposites can be successfully obtained with optimized electrochemical response, promising for applications as supercapacitors and artificial muscles. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 579–588     

PMMA/MMT nanocomposites prepared by one-step in situ intercalative solution polymerization

Poly(methylmetacrylate)/montmorillonite (PMMA)/(MMT) nanocomposites were prepared by one-step in situ intercalative solution polymerization involving simultaneous modification of MMT with quaternary ammonium salts (QAS), polymerization and polymer intercalation. Polymerization proceeded at 70 °C in a mixture of ethanol and water, whereas the nanocomposite was precipitated with only water. Four QAS’s with different alkyl chain lengths, as well as a QAS with an additional acrylic group, were used to study the influence of the type of quaternary ammonium salt on intercalation. The largest extent of intercalation was achieved in nanocomposites with the QAS having one long alkyl (C16) chain. The obtained PMMA/MMT intercalated nanocomposites exhibited a higher glass transition temperature, better thermal stability, and improved solvent resistance than the pure PMMA.     

Tubular polypyrrole synthesized by in situ doping polymerization in the presence of organic function acids as dopants

Tubular polypyrrole (PPy) could be synthesized by in situ doping polymerization in the presence of β‐naphthalene sulfonic acid (NSA) as dopant. The resultant tubular PPy–NSA not only exhibits high room temperature conductivity (ς_RT = 10 S/cm) but is also soluble in m‐cresol. The molecular structure of PPy–NSA is identical to the characteristic structure of PPy synthesized by a conventional method. It has been demonstrated that NSA dopant with large molecular size and plate–lebe structure is a key factor to control formation of tubular PPy–NSA. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1443–1449, 1999     

Electrical conductivity of poly(ethylene terephthalate)/expanded graphite nanocomposites prepared by in situ polymerization

Nanocomposites based on poly(ethylene terephthalate) (PET) and expanded graphite (EG) have been prepared by in situ polymerization. Morphology of the nanocomposites has been examined by electronic microscopy. The relationship between the preparation method, morphology, and electrical conductivity was studied. Electronic microscopy images reveal that the nanocomposites exhibit well dispersed graphene platelets. The incorporation of EG to the PET results in a sharp insulator‐to‐conductor transition with a percolation threshold (?_c) as low as 0.05 wt %. An electrical conductivity of 10^?3 S/cm was achieved for 0.4 wt % of EG. The low percolation threshold and relatively high electrical conductivity are attributed to the high aspect ratio, large surface area, and uniform dispersion of the EG sheets in PET matrix. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Preparation and characterization of polymer/silica nanocomposites via double in situ miniemulsion polymerization

Polymer/SiO₂ nanocomposite microspheres were prepared by double in situ miniemulsion polymerization in the presence of methyl methacrylate, butyl acrylate, γ‐methacryloxy(propyl) trimethoxysilane, and tetraethoxysilane (TEOS). By taking full advantage of phase separation between the growing polymer particles and TEOS, inorganic/polymer microspheres were fabricated successfully in a one‐step process with the formation of SiO₂ particles and the polymerization of organic monomers taking place simultaneously. The morphology of nanocomposite microspheres and the microstructure, mechanical properties, thermal properties, and optical properties of the nanocomposite films were characterized and discussed. The results showed that hybrid microspheres had a raspberry‐like structure with silica nanoparticles on the shells of polymer. The silica particles of about 20 nm were highly dispersed within the nanocomposite films without aggregations. The transmittance of nanocomposite film was comparable to that of the copolymer film at around 70–80% from 400 to 800 nm. The mechanical properties and the fire‐retardant behavior of the polymer matrix were improved by the incorporation of silica nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3128–3134, 2010     

Preparation of polystyrene/montmorillonite nanocomposites using a new radical initiator-montmorillonite hybrid via in situ intercalative polymerization

Polystyrene/montmorillonite (PS/MMT) nanocomposites were prepared by in situ free radical intercalative polymerization, using 1, 3 and 5 wt% of a new cationic radical initiator-MMT hybrid. The corresponding nanocomposites were designated as PS/MMT-1, PS/MMT-3 and PS/MMT-5, respectively. The silicate layers were well exfoliated and randomly dispersed in the PS/MMT-1 and PS/MMT-3, but were less exfoliated in the PS/MMT-5, due to the predominant extra-gallery polymerization over the intra-gallery polymerization. The unique properties of nanocomposites resulted from the strong interactions between the nano-sized silicate layer surfaces and the polymer chains. The onset temperature of thermal degradation, and the glass transition temperature, increased with increasing hybrid content, up to 3 wt%. The molecular weights of the PS in the PS/MMT-1 and PS/MMT-3 were less than those calculated theoretically, due to the predominant intra-gallery polymerization.     

In situ polymerization and morphology of polypyrrole obtained in water‐soluble polymer templates

Several water‐soluble polymers were used as templates for the in situ polymerization of pyrrole to determine their effect on the generation of nanosized polypyrrole (PPy) particles. The polymers used include: polyvinyl alcohol (PVA), polyethylene oxide (PEO), poly(vinyl butyral), polystyrene sulfonic acid, poly(ethylene‐alt‐maleic anhydride) (PEMA), poly(octadecene‐alt‐maleic anhydride), poly(N‐vinyl pyrrolidone), poly(vinyl butyral‐co‐vinyl alcohol‐co‐vinyl acetate), poly(N‐isopropyl acrylamide), poly(ethylene oxide‐block‐propylene oxide), hydroxypropyl methyl cellulose, and guar gum. The oxidative polymerization of pyrrole was carried out with FeCl₃ as an oxidant. The morphology of PPy particles obtained after drying the resulting aqueous dispersions was examined by optical microscopy, and selected samples were further analyzed via atomic force microscopy. Among the template polymers, PVA was the most efficient in generating stable dispersions of PPy nanospheres in water, followed by PEO and PEMA. The average size of PPy nanospheres was in the range of 160 nm and found to depend on the molecular weight and concentration of PVA. Model reactions and kinetics of the polymerization reaction of pyrrole in PVA were carried out by hydrogen ¹H NMR spectroscopy using ammonium persulfate as an oxidant. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and characterization of carbon nanotube/polypyrrole core–shell nanocomposites via in situ inverse microemulsion

We demonstrate here a feasible approach to the preparation of multiwalled carbon nanotube (MWNT)/polypyrrole (PPy) core–shell nanowires by in situ inverse microemulsion. Transmission electron microscopy and scanning electron microscopy showed that the carbon nanotubes were uniformly coated with a PPy layer with a thickness of several to several tens of nanometers, depending on the MWNT content. Fourier transform infrared spectra suggested that there was strong interaction between the π‐bonded surface of the carbon nanotubes and the conjugated structure of the PPy shell layer. The thermal stability and electrical conductivity of the MWNT/PPy composites were examined with thermogravimetric analysis and a conventional four‐probe method. In comparison with pure PPy, the decomposition temperature of the MWNT/PPy (1 wt % MWNT) composites increased from 305 to 335 °C, and the electrical conductivity of the MWNT/PPy (1 wt % MWNT) composites increased by 1 order of magnitude. The current–voltage curves of the MWNT/PPy nanocomposites followed Ohm's law, reflecting the metallic character of the MWNT/PPy nanocomposites. The cyclic voltammetry measurements revealed that PPy/MWNT composites showed an enhancement in the specific charge capacity with respect to that of pure PPy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6105–6115, 2005     

Pendant cyclic carbonate‐polymer/Na‐smectite nanocomposites via in situ intercalative polymerization and solution intercalation

Nanocomposites of sodium smectite with polyether‐ and polystyrene‐containing pendant cyclic carbonates offer a novel approach to improving hydraulic barrier properties of Na‐smectite liners to saline leachates. The cyclic carbonate polyethers were prepared by cationic ring opening polymerization of a cyclic carbonate‐containing epoxide, whilst polystyrene polymers having pendant cyclic carbonate groups were obtained from radical photopolymerization of styrene. Na‐smectite nanocomposites of these polymers were formed via clay in situ polymerization and solution intercalation methods. X‐ray diffraction (XRD) and FT‐IR analysis confirmed that the polyether can be intercalated within the layers of smectite via in situ as well as solution intercalation of the pre‐formed polymer. The cyclic carbonate polyether nanocomposite was more resistant to leaching in 3M aqueous sodium chloride than its respective cyclic carbonate. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2421–2429     

In situ polymerization of ethylene with bis(imino)pyridine iron(II) catalysts supported on clay: The synthesis and characterization of polyethylene–clay nanocomposites

Polyethylene–clay nanocomposites were synthesized by in situ polymerization with 2,6‐bis[1‐(2,6‐diisopropylphenylimino)ethyl] pyridine iron(II) dichloride supported on a modified montmorillonite clay pretreated with methylaluminoxane (MAO). The catalysts and the obtained nanocomposites were examined with wide‐angle X‐ray scattering. The exfoliation of the clay was further established by transmission electron microscopy. Upon the treatment of the clay with MAO, there was an increase in the d‐spacing of the clay galleries. No further increase in the d‐spacing of the galleries was observed with the iron catalyst supported on the MAO‐treated clay. The catalyst activity for ethylene polymerization was independent of the Al/Fe ratio. The exfoliation of the clay inside the polymer matrix depended on various parameters, such as the clay content, catalyst content, and Al/Fe ratio. The crystallinity percentage and crystallite size of the nanocomposites were affected by the degree of exfoliation of the clay. Moreover, when ethylene was polymerized with a mixture of the homogeneous iron(II) catalyst and clay, the degree of exfoliation was significantly lower than when the polymerization was performed with a preformed clay‐supported catalyst. This observation suggested that in the supported catalyst, at least some of the active centers resided within the galleries of the clay. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 304–318, 2005     

Phase transition in polyamide‐66/montmorillonite nanocomposites on annealing

The crystalline‐phase transition in polyamide‐66/montmorillonite nanocomposites before melting was investigated by in situ X‐ray diffraction and is reported for the first time in this work. The phase‐transition temperature in the nanocomposites was 170 °C, 20 °C lower than that in polyamide‐66. The lower phase‐transition temperature of the nanocomposites could be attributed to the γ‐phase‐favorable environment caused by silicate layers. Meanwhile, the addition of silicate layers changed the crystal structure of the polyamide‐66 matrix and influenced the phase‐transition behavior. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 63–67, 2003     

Conducting polyaniline‐coated nano silica by in situ chemical oxidative grafting polymerization

Polyaniline (PAni) grafted nano silica were synthesized successfully by in situ polymerization of aniline (An) using ammonium persulphate (APS) as oxidant by three procedures: Firstly, γ‐(2,3‐epoxypropoxy)propyltrimethoxysilane (EPTMS) reacted with nano silica. Secondly, the EPTMS modified nano silica reacted with An as an initiator site introduced onto the silica surface, and finally PAni grafted silica was obtained by in situ chemical oxidative An. The chemical grafting of PAni was confirmed by FTIR and UV–Vis. The percentages of grafting EPTMS and An onto nano silica were 24.5 wt% and 10.3 wt%, respectively, calculated from elemental analysis (EA), while the percentage of grafting PAni was 157.7 wt% as a mass ratio of the grafting PAni and charged nano silica, investigated by TGA. In addition, characteristic agglomerate morphology of PAni was observed in the composite by SEM. The electrical conductivity of the product was 2.6 × 10^?6 S cm^?1 and it manifested that the resulted product was a typical semiconductor. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and characterization of conducting polythiophene/carbon nanotubes composites

Conducting polythiophene (PTh)/single‐wall carbon nanotubes (SWNTs) composites were synthesized by the in situ chemical oxidative polymerization method. The resulting cablelike morphology of the composite (SWNT–PTh) structures was characterized with elemental analysis, X‐ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared, ultraviolet–visible spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, X‐ray diffraction, and transmission electron microscopy. The standard four‐point‐probe method was used to measure the conductivity of the samples. Field emission scanning electron microscopy and transmission electron microscopy analysis revealed that the SWNT–PTh composites were core (SWNTs) and shell (PTh) hybrid structures. Spectroscopic analysis data for the composites were almost identical to those for PTh, supporting the idea that SWNTs served as templates in the formation of a coaxial nanostructure for the composites. The physical properties of the composites were measured and also showed that the SWNTs were modified by conducting PTh with an enhancement of various properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5283–5290, 2006