Synthesize and characterization of styrene‐N‐phenyl maleimide/montmorillonite nanocomposites prepared through emulsion polymerization

Composites of organomodified (OMMT) and pristine montmorillonite (MMT) intercalated by styrene‐N‐phenyl maleimide (PMI) copolymer were prepared by emulsion intercalative polymerization. X‐ray diffraction (XRD) and transmission electron microscopy results show that the dispersability of clay in the matrix was greatly improved by the incorporation of polar moiety PMI. The dispersability of OMMT in the matrix is better than MMT. XRD patterns of the extracted nanocomposites showed that d₀₀₁ of the clay are much larger than that of the original OMMT and MMT, which indicates that the interaction of copolymer with the clay layers was greatly improved by incorporation with polar monomer PMI. The thermal property of the composites was greatly improved by the intercalation with clay. The DSC results showed that the glass transition of the composites became inconspicuous, which indicated that the movement of the polymer segment was extremely confined by the clay layer. The consistency factor of the melts of the composites increased monotonically with a decreasing flow index showing stronger shear thinning property of the composites. The rheological activity energy of the composites decreased more than that of the pure copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1010–1015, 2005     

Synthesis and characterization of poly(urethane‐benzoxazine)/clay hybrid nanocomposites

Poly(urethane‐benzoxazine)/clay hybrid nanocomposites (PU/Pa–OMMTs) were prepared from an in situ copolymerization of a polyurethane (PU) prepolymer and a monofunctional benzoxazine monomer, 3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (Pa), in the presence of an organophilic montmorillonite (OMMT), by solvent method using DMAc. OMMT was made from cation‐exchange of Na‐montmorillonite (MMT) with dodecyl ammonium chloride. The formation of the exfoliated nanocomposite structures of PU/Pa‐OMMT was confirmed by XRD from the disappearance of the peak due to the basal diffraction of the layer‐structured clay found in both MMT and OMMT. DSC showed that, in the presence of OMMT, the curing temperature of PU/Pa lowered by ca. 60°C for the onset and ca. 20°C for the maximum. After curing at 190°C for 1 h, the exothermic peak on DSC disappeared. All the obtained films of PU/Pa–OMMT were deep yellow and transparent. As the content of OMMT increased, both the tensile modulus and strength of PU/Pa–OMMT films increased, while the elongation decreased. The characteristics of the PU/Pa–OMMT films changed from plastics to elastomers depending on OMMT content and PU/Pa ratio. PU/Pa–OMMT films also exhibited excellent resistance to the solvents such as tetrahydrofuran, N,N‐dimethylformamide and N‐methyl‐2‐pyrrolidinone. The thermal stability of PU/Pa were enhanced remarkably even with small amount of OMMT. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4075–4083, 2003     

The effect of clay modification on the mechanical properties of poly(methyl methacrylate)/organomodified montmorillonite nanocomposites prepared by in situ suspension polymerization

Poly(methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ suspension polymerization. MMT was previously organically modified by different modification agents [dioctadecyl dimethyl ammonium chloride (DODAC) and methacrylatoethyltrimethyl ammonium chloride (MTC)] and different modification method (cation‐exchange reaction and grafting reaction), ultimately giving rise to five kinds of organomodified MMT (OMMT). The structure of the OMMT was studied by Wide angle X‐ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FTIR). Meanwhile, the structure of the PMMA/MMT nanocomposites microspheres was also investigated by WAXD. The molecular weight of the polymers extracted from PMMA/MMT nanocomposites was measured by gel permeation chromatograph (GPC). Finally, the mechanical properties of these PMMA/MMT nanocomposites were studied in detail. It was found that large interlayer spacing (d₀₀₁) of OMMT could not entirely ensure an exfoliated structure of resultant PMMA/MMT nanocomposites, while OMMT with relative small d₀₀₁ could still yield exfoliated structure as long as the compatibility between OMMT and polymer matrix was favorable. In addition, the results of mechanical investigation indicated that the compatibility between OMMT and PMMA matrix turned out to be the dominant factor deciding the final mechanical properties of PMMA/MMT nanocomposites. POLYM. COMPOS., 37:1705–1714, 2016. © 2014 Society of Plastics Engineers     

Polypropylene nanocomposites prepared with natural and ODTABr‐modified montmorillonite

In this study, the main goal is to obtain montmorillonite nanocomposites of polypropylene (PP). To achieve this goal, a two‐phase study was performed. In the first part of the work, organomodified clay (OMMT) was synthesized and characterized. Octadecyltrimethylammonium bromide (ODTABr) cationic surfactant was added to the clay (Na‐activated montmorillonite, MMT) dispersions in different concentrations in the range of 5 × 10^?5–1 × 10^?2 mol/L. Rheologic, electrokinetic, and spectral analyses indicated that ODTABr has interacted with MMT at optimum conditions when the concentration was 1 × 10^?2 mol/L. In the second part, modified (OMMT) and unmodified (MMT) montmorillonite were used to obtain PP nanocomposites (OMMT/PP and MMT/PP, respectively). The nanocomposites were prepared by melt intercalation where the montmorillonite contents were 1 or 5% (w/w) for each case. The thermal analyses showed that the thermal properties of OMMT/PP nanocomposites were better than MMT/PP, and both of them were also better than pure polymer. Increase in the concentration of MMT (or OMMT) decreased the thermal resistance. Based on the IR absorption intensity changes of regularity and conformational bands, it is found that the content of the helical structure of macromolecular chains has increased with increasing concentrations of both MMT and OMMT in the nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Solid‐state graft polymerization of styrene in spherical polypropylene particles in the presence of montmorillonite

In this work, cetyltrimethyl ammonium bromide and methacryloyloxyethyhrimethyl ammonium chloride were used to prepare organophilic montmorillonite (O‐MMT). Then, polypropylene (PP)–clay nanocomposites were prepared by the in situ grafting polymerization of styrene (St)‐containing O‐MMT onto PP with tert‐butyl perbenzoate as an initiator in the solid state. Fourier transform infrared spectroscopy, gel permeation chromatography, transmission electron microscopy, and X‐ray diffraction were applied to study the structure of the layered silicate and modified PP. The surfaces of the composites and, thus, the distribution of the clay in the PP matrix were characterized by scanning electron microscopy. The rheology and mechanical properties were studied and are discussed. According to the characterization results, OMMT and St were already grafted onto the PP main chain. Also, the intercalated structure of montmorillonite could be stabilized, and a stable exfoliated structure could be attained. Namely, intercalated PP/OMMT nanocomposites were obtained. The rheological results clearly show that these PP/OMMT nanocomposites had long‐chain‐branched structures. The peroxide modification of PP had minor effects on the tensile and bending strengths of the modified PP; however, this modification resulted in a significant reduction in the impact strength. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of the Addition of Toluene on the Structure and Properties of Styrene‐Isoprene‐Butadiene Rubber/Montmorillonite Nanocomposites

Summary: Styrene‐isoprene‐butadiene rubber/montmorillonite nanocomposites were synthesized by the addition of toluene into clay and living anionic polymerization. These silicate layers (B‐M) were exfoliated within 30 min after polymerization initiation, whereas the layers in the nanocomposites prepared without using toluene (A‐M) were only partially exfoliated and not well‐dispersed in the matrix. The results of TEM and X‐ray diffraction revealed disperse silicates and a strong interaction between the terpolymer matrix and clay in the B‐M nanocomposites. The B‐M‐exfoliated nanocomposites exhibited higher decomposition and glass transition temperatures, storage moduli, tensile strengths and elongations at the break than those of the pure terpolymer and A‐M. With an organophilic montmorillonite (OMMT) content of 3 wt.‐%, the exfoliated nanocomposite exhibited the best thermal stability and mechanical properties. In addition, GPC and ¹H NMR results showed that the introduction of OMMT caused a slight increase in the of terpolymer, but hardly affected the microstructure of the terpolymer independent of the preparation method. Thus, the addition of toluene plays an important role in enhancing the dispersion of OMMT, which leads to the improvement of the structure and properties of the B‐M nanocomposites.

TEM image of the SIBR/MMT nanocomposite.     

Complex formation of montmorillonite clay with polymers. Part 2: The use of montmorillonite clay–vinyl monomer complex as a comonomer in the copolymerization reaction of styrene–acrylonitrile monomers

The bulk copolymerization of styrene–acrylonitrile monomers using styrene‐N⁺–montmorillonite complex as a comonomer in the polymerization was studied. The X‐ray diffraction (XRD) analysis showed that part of the styrene‐N⁺–montmorillonite complex remained non‐dispersed (immiscible) and the copolymer was excluded from the interlayer of the immiscible part of the clay. The successive chemical extraction process revealed that a reasonable amount of the styrene–acrylonitrile copolymer was directly attached to the styrene‐N⁺–montmorillonite complex and enveloped the clay. Highly exfoliated clay lamella and nanospheres (3–5 nm) were observed by transmission electron microscopy (TEM). The montmorillonite clay assume two different morphologies, immiscible and exfoliated, on the basis of the XRD and TEM data. A simple method of calculation of the ratio of the exfoliated/immiscible amounts of the clay indicated that the amount of the styrene‐N⁺–montmorillonite complex exfoliated into separate lamella was 40 % (w/w) of the amount of the clay samples containing 2 % of the (styrene‐N⁺–montmorillonite complex) clay. This amount of exfoliated clay decreases with the increase of the concentration of the clay. The presence of the styrene‐N⁺–montmorillonite clay in the copolymerization reaction had a minor effect on both the copolymer composition and the molecular weight. Modification of the clay with the derivatized styrene monomer can achieve a nanocomposite using a percentage no more than 4 % (w/w) of complex in the copolymer. Copyright © 2004 Society of Chemical Industry     

Preparation and characterization of polystyrene–clay nanocomposites by free‐radical polymerization

The polymerizable cationic surfactant, vinylbenzyldimethylethanolammouium chloride (VBDEAC), was synthesized to functionalize montmorillonite (MMT) clay and used to prepare exfoliated polystyrene–clay nanocomposites. The organophilic MMT was prepared by Na⁺ exchanged montmorillonite and ammonium cations of the VBDEAC in an aqueous medium. Polystyrene–clay nanocomposites were prepared by free‐radical polymerization of the styrene containing intercalated organophilic MMT. Dispersion of the intercalated montmorillonite in the polystyrene matrix determined by X‐ray diffraction reveals that the basal spacing is higher than 17.6 nm. These nanocomposites were characterized by differential scanning calorimetry (DSC), transmission electron micrograph (TEM), thermal gravimetric analysis (TGA), and mechanical properties. The exfoliated nanocomposites have higher thermal stability and better mechanical properties than the pure polystyrene. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1370–1377, 2002     

Styrene–butadiene–styrene/montmorillonite nanocomposites synthesized by anionic polymerization

We successfully synthesized an exfoliated styrene–butadiene–styrene triblock copolymer (SBS)/montmorillonite nanocomposite by anionic polymerization. Gel permeation chromatography showed that the introduction of organophilic montmorillonite (OMMT) resulted in a small high‐molecular‐weight fraction of SBS in the composites, leading to a slight increase in the weight‐average and number‐average molecular weights as well as the polydispersity index. The results from ¹H‐NMR revealed that the introduction of OMMT almost did not affect the microstructure of the copolymer when the OMMT concentration was lower than 4 wt %. Transmission electron microscopy and X‐ray diffraction showed a completely exfoliated nanocomposite, in which both polystyrene and polybutadiene blocks entered the OMMT galleries, leading to the dispersion of OMMT layers on a nanoscale. The exfoliated nanocomposite exhibited higher thermal stability, glass‐transition temperature, elongation at break, and storage modulus than pure SBS. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Preparation of exfoliated high‐impact polystyrene/MMT nanocomposites via in situ polymerization under controlling viscosity of the reaction medium

Exfoliated high‐impact polystyrene (HIPS)/montmorillonite (MMT) nanocomposites were prepared via in situ polymerization of styrene in the presence of polybutadiene, using an intercalated cationic radical initiator‐MMT hybrid (organoclay). In the solution polymerization in toluene, the silicate layers of the clay were well exfoliated, due to the low extra‐gallery viscosity that can facilitate the diffusion of styrene monomers into the clay layers during the polymerization. The exfoliated HIPS/MMT nanocomposites were also successfully prepared by controlling the viscosity of the reaction medium with prolong swelling of the organoclay in styrene, prior to bulk polymerization. The HIPS/MMT nanocomposites, obtained from bulk polymerization, exhibited a significant improvement in thermal stability, compared to those obtained from solution polymerization as well as the pure polymer counterparts. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers     

Effect of polymer matrix/montmorillonite compatibility on morphology and melt rheology of polypropylene nanocomposites

In this study, Ca²⁺‐montmorillonite (Ca²⁺‐MMT) and organo‐montmorillonite (OMMT) were modified by three compatibilizers with different degrees of polarity [poly(ethylene glycol) (PEG), alkyl‐PEG, and polypropylene (PP)‐g‐PEG]. PP/MMT nanocomposites were prepared by melt blending and characterized using X‐ray diffraction and transmission electron microscopy. The results showed the degree of dispersion of OMMT in the PP/PP‐g‐PEG/OMMT (PMOM) nanocomposite was considerably higher than those in the PP/PEG/OMMT and PP/alkyl‐PEG/OMMT nanocomposites, which indicated that the dispersion was relative to the compatibility between modified OMMT and PP matrix. Linear viscoelasticity of PP/MMT nanocomposites in melt states was investigated by small amplitude dynamic rheology measurements. With the addition of the modified MMT, the shear viscosities and storage modulus of all the PP/MMT nanocomposites decreased. It can be attributed to the plasticization effect of PEG segments in the three modifiers. This rheological behavior was different from most surfactant modified MMT nanocomposites which typically showed an increase in dynamic modulus and viscosity relative to the polymer matrix. The unusual rheological observations were explained in terms of the compatibility between the polymer matrix and MMT. In addition, the mechanical properties of PP/MMT nanocomposites were improved. A simultaneous increase in the tensile strength and toughness was observed in PP/PMOM nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of the nature and combinations of solvents in the intercalation of clay with block copolymers on the properties of polymer nanocomposites

Polystyrene (PS) nanocomposites were prepared by the free‐radical polymerization of styrene in the presence of organically modified montmorillonite (MMT) clays. MMT clay was modified with a low‐molecular‐weight and quarternized block copolymer of styrene and 4‐vinylpyridine [poly(styrene‐b‐4‐vinylpyridine) (SVP)] with 36.4 wt % PS and 63.6 wt % poly(4‐vinylpyridine) (P4VP). Special attention was paid to the modification, which was carried out in different compositions of a solvent mixture of tetrahydrofuran (THF) and water. The swelling behavior of the MMT clay was studied by an X‐ray diffraction technique. The diffraction peak shifted to lower 2θ angles for all of the modified clays, which indicated the intercalation of the quarternized SVP copolymer into the MMT layers in different degrees. Higher interlayer distances, which showed a high degree of block copolymer insertion, were obtained for solvent compositions with THF in water. The resultant nanocomposites were characterized by X‐ray diffraction, atomic force microscopy, scanning electron microscopy, thermogravimetric analysis, and dynamic mechanical analysis. The desired exfoliated nanocomposite structure was achieved when the MMT modification was conducted in 50 or 66 wt % THF, whereas the other modifications all resulted in intercalated structures. The resulting exfoliated nanocomposite was found to have better thermal stability and dynamic mechanical performance compared to the others, even with 2% clay loading. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of poly(butyl acrylate‐co‐methyl methacrylate)/montmorillonite waterborne nanocomposite via semibatch emulsion polymerization

Poly(butyl acrylate‐co‐methyl methacrylate)‐montmorillonite (MMT) waterborne nanocomposites were successfully synthesized by semibatch emulsion polymerization. The syntheses of the nanocomposites were performed in presence of sodium montmorillonite (Na‐MMT) and organically modified montmorillonite (O‐MMT). O‐MMT was used directly after the modification of Na‐MMT with dimethyl dioctadecyl ammonium chloride. Both Na‐MMT and O‐MMT were sonified to obtain nanocomposites with 47 wt % solids and 3 wt % Na‐MMT or O‐MMT content. Average particle sizes of Na‐MMT nanocomposites were measured as 110–150 nm while O‐MMT nanocomposites were measured as 200–350 nm. Both Na‐MMT and O‐MMT increased thermal, mechanical, and barrier properties (water vapor and oxygen permeability) of the pristine copolymer explicitly. X‐ray diffraction and transmission electron microscope studies show that exfoliated morphology was obtained. The gloss values of O‐MMT nanocomposites were found to be higher than that of the pristine copolymer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42373.     

Effect of organic modifiers and silicate type on filler dispersion,thermal, and mechanical properties of ABS‐clay nanocomposites

Acrylonitrile–butadiene–styrene (ABS)–clay composite and intercalated nanocomposites were prepared by melt processing, using Na‐montmorillonite (MMT), several chemically different organically modified MMT (OMMT) and Na‐laponite clays. The polymer–clay hybrids were characterized by WAXD, TEM, DSC, TGA, tensile, and impact tests. Intercalated nanocomposites are formed with organoclays, a composite is obtained with unmodified MMT, and the nanocomposite based on synthetic laponite is almost exfoliated. An unintercalated nanocomposite is formed by one of the organically modified clays, with similar overall stack dispersion as compared to the intercalated nanocomposites. T_g of ABS is unaffected by incorporation of the silicate filler in its matrix upto 4 wt % loading for different aspect ratios and organic modifications. A significant improvement in the onset of thermal decomposition (40–44°C at 4 wt % organoclay) is seen. The Young's modulus shows improvement, the elongation‐at‐break shows reduction, and the tensile strength shows improvement. Notched and unnotched impact strength of the intercalated MMT nanocomposites is lower as compared to that of ABS matrix. However, laponite and overexchanged organomontmorillonite clay lead to improvement in ductility. For the MMT clays, the Young's modulus (E) correlates with the intercalation change in organoclay interlayer separation (Δd₀₀₁) as influenced by the chemistry of the modifier. Although ABS‐laponite composites are exfoliated, the intercalated OMMT‐based nanocomposites show greater improvement in modulus. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

New fabricate of styrene-butadiene rubber/montmorillonite nanocomposites by anionic polymerization

Styrene-butadiene rubber/montmorillonite (SBR/MMT) nanocomposites were successfully synthesized by in situ living anionic polymerization with n-BuLi as initiator. The results from kinetics study and ¹H NMR indicated that the addition of organophilic montmorillonite (OMMT) did not changed the living copolymerization and the components of the copolymer on the whole when OMMT content was lower than 3 wt %. However, gel permeation chromatography showed that the introduction of OMMT resulted in small amount of high-molecular weight fraction of SBR in the composites, leading to an increase in the weight-average molecular weight and polydispersity index, but the unchangeableness of the number-average molecular weight. The result from transmission electron microscopy and X-ray diffraction revealed that a completely exfoliated structure existed in the nanocomposite with 25 wt % styrene and OMMT content from 1 to 4 wt %, and styrene played an important role in the expanding of OMMT layers. Moreover, the nanocomposites possessed higher glass-transition temperature, thermal stability, tensile strength and elongation at break than SBR when the OMMT content ranged from 2.5 to 4 wt %. A schema was proposed to illustrate the formation of the nanocomposite and the exfoliation structure with physical cross-linking between SBR chains and OMMT.     

Properties of water‐soluble acrylic copolymer/montmorillonite nanocomposites for warp sizing

Acrylic copolymer/montmorillonite (MMT) nanocomposites for warp sizing were prepared in the presence of Na⁺‐MMT by the in situ intercalative polymerization of acrylic acid, acrylamide, and methyl acrylate in water solution. The properties of the solution and cast film were tested according to an application in sizing process of the nanocomposite size with various MMT contents. The results indicate that, for an exfoliated structure corresponding to the MMT content increasing to 7 wt %, the performance parameters of solution viscosity, glass‐transition temperature, and tensile strength of the film increased and the moisture sorption, abrasion loss, and elongation at break of the film decreased. When the intercalated structure of MMT was 9 wt %, the gathered MMT layers acted as a common inorganic filler in the copolymer matrix, with limited contribution to the properties of the composite. The adhesion work of the nanocomposite solution was calculated by use of the Young–Dupre relation, which showed maximum values at an MMT content of 3 wt % on the surfaces of both the polyester and cellulose films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of clay modification on the morphological,mechanical, and thermal properties of polyamide 6/polypropylene/montmorillonite nanocomposites

Polyamide 6/polypropylene (PA6/PP = 70/30 parts) blends containing 4 phr (parts per hundred resin) of organophilic montmorillonite (OMMT) were prepared by melt compounding. The sodium montmorillonite (Na‐MMT) was modified using three different types of alkyl ammonium salts, namely dodecylamine, 12‐aminolauric acid, and stearylamine. The effect of clay modification on the morphological and mechanical properties of PA6/PP nanocomposites was investigated using x‐ray diffraction (XRD), transmission electron microscopy (TEM), tensile, flexural, and impact tests. The thermal properties of PA6/PP nanocomposites were characterized using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and heat distortion temperature (HDT). XRD and TEM results indicated the formation of exfoliated structure for the PA6/PP nanocomposites prepared using stearylamine modified montmorillonite. On the other hand, a mixture of intercalated and exfoliated structures was found for the PA6/PP nanocomposites prepared using 12‐aminolauric acid and dodecylamine modified montmorillonite. Incorporation of OMMT increased the stiffness but decreased the ductility and toughness of PA6/PP blend. The PA6/PP nanocomposite containing stearylamine modified montmorillonite showed the highest tensile, flexural, and thermal properties among all nanocomposites. This could be attributed to better exfoliated structure in the PA6/PP nanocomposite containing stearylamine modified montmorillonite. The storage modulus and HDT of PA6/PP blend were increased significantly with the incorporation of both Na‐MMT and OMMT. The highest value in both storage modulus and HDT was found in the PA6/PP nanocomposite containing stearylamine modified montmorillonite due to its better exfoliated structure. POLYM. COMPOS., 31:1156–1167, 2010. © 2009 Society of Plastics Engineers     

Polystyrene nanocomposite materials by in situ polymerization into montmorillonite–vinyl monomer interlayers

A different series of new polystyrene–clay nanocomposites have been prepared by grafting polymerization of styrene with vinyl‐montmorillonite (MMT) clay. The synthesis was achieved through two steps. The first step is the modification of clay with the vinyl monomers, such as N,N‐dimethyl‐n‐octadecyl‐4‐vinylbenzyl‐ammonium chloride, n‐octadecyl‐4‐vinylbenzyl‐ammonium chloride, triphenyl‐4‐vinylbenzyl‐phosphonium chloride, and tri‐n‐butyl‐4‐vinylbenzyl‐phosphonium chloride. The second step is the polymerization of styrene with different ratios of vinyl‐MMT clay. The materials produced were characterized by different physical and chemical methods: (1) IR spectra, confirming the intercalation of the vinyl‐cation within the clay interlayers; (2) thermogravimetric analysis (TGA), showing higher thermal stability for PS–nanocomposites than polystyrene (PS) and higher thermal stability of nanocomposites with of phosphonium moieties than nanocomposites with ammonium moieties; (3) swelling measurements in different organic solvents, showing that the swelling degree in hydrophobic solvents increases as the clay ratio decreases; (4) X‐ray diffraction (XRD), illustrating that the nanocomposites were exfoliated at up to a 25 wt % of organoclay content; and (5) scanning electron microscopy (SEM), showing a complete dispersion of PS into clay galleries. Also, transmission electron microscopy (TEM) showed nanosize spherical particles of ～ 150–400 nm appearing in the images. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3739–3750, 2007     

Photodegradation of some low‐density polyethylene–montmorillonite nanocomposites containing an oligomeric compatibilizer

The photo‐oxidation behavior at the exposed surfaces of maleated low‐density polyethylene [LDPE poly(ethylene‐co‐butylacrylate‐co‐maleic anhydride) (PEBAMA)] and montmorillonite (MMT) composites was studied using attenuated total reflection Fourier transform infrared spectroscopy, X‐ray diffraction (XRD), transmission electron microscopy (TEM), and mechanical testing. Two different MMT clays were used with the maleated polyethylene, an unmodified clay, MMT, and an organically modified montmorillonite (OMMT) clay which was significantly exfoliated in the composite. The morphologies of sample films were examined by XRD and TEM. The results were explained in terms of the effect of the compatibilizing agent PEBAMA on the clay dispersion. It was found that the OMMT particles were exfoliated in the polymer matrix in the presence of the PEBAMA, whereas the MMT clay particles were agglomerated in this matrix. Both mechanical and spectroscopic analyses showed that the rates of photo oxidative degradation of the LDPE‐PEBAMA–OMMT were higher than those for LDPE and LDPE‐PEBAMA–MMT. The acceleration of the photo‐oxidative degradation for LDPE‐PEBAMA–OMMT is attributed to the effects of the compatibilizer and the organic modifier in the composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40788.     

Preparation and characterization of exfoliated organic montmorillonite/poly(3,4‐ethyldioxythiophene) nanocomposites

Montmorillonite, organically modified by octadecylammine salt, has been adopted to successfully fabricate the exfoliated organic montmorillonite/poly(3,4‐ethyldioxythiophene) (OMMT/PEDOT) nanocomposites by in situ polymerization in aqueous media. Hydrochloric acid, 1,5‐naphthalenedisulfonic acid, and sodium benzenesulphonate have been employed to activate the polymerization of 3,4‐ethyldioxythiophene by offering active sites on the layers of montmorillonite. The resulting exfoliated nanocomposites have been characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, thermogravimetric analysis, and electrical conductivity measurement and showed controllable conductivity in the range of 10^?7 to 10^?2 S/cm and improved thermal stability compared with pure PEDOT. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009