Effect of ethylene glycidyl methacrylate compatibilizer on the structure and mechanical properties of clay nanocomposites modified with ethylene vinyl acetate copolymer

The structure and mechanical properties of clay modified with ethylene vinyl acetate copolymer in the presence of ethylene glycidyl methacrylate (EGMA) were investigated as a function of compatibilizer and clay contents. The structure and properties were determined by X‐ray diffraction, transmission electron microscopy, differential scanning calorimetry, and thermogravimetric analysis (TGA). The presence of EGMA caused strong exfoliation of the clay in the polymer matrix, although at higher clay contents, some clay layers still existed. The more effective exfoliation, however, did not seem to substantially influence the tensile properties of the nanocomposites because the EGMA itself had a much stronger influence, which overshadowed any possible influence that the EGMA–clay interaction may have had on these properties. The thermal stability of the nanocomposites (as studied by TGA) improved in the presence of EGMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4095–4101, 2007     

Melt‐intercalation nanocomposites with fluorinated polymers and a correlation for nanocomposite formation

Various fluorinated polymers were investigated to produce polymer nanocomposites with special clays. Natural and organically treated montmorillonite clays were melt‐compounded with the polymers. Characterization by wide‐angle X‐ray scattering and transmission electron microscopy showed the separation of montmorillonite layers and the formation of polymer nanocomposites. Organically treated montmorillonite clay dispersed in poly(vinylidene fluoride) and various vinylidene fluoride copolymers and formed nanocomposites. Natural and organophilic clays were not well dispersed in other fluorinated copolymers and polyethylene. A correlation was developed for the formation of polymer–clay nanocomposite structures in chlorinated and fluorinated polymers in terms of the dielectric constant. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1061–1071, 2004     

Effect of clay on the properties of poly(styrene‐co‐acrylonitrile)–clay nanocomposites

Clay‐dispersed poly(styrene‐co‐acrylonitrile) nanocomposites (PSAN) were synthesized by a free radical polymerization process. The montmorillonite (MMT) was modified by a cationic surfactant hexadecyltrimethylammonium chloride. The structures of PSAN were determined by wide‐angle X‐ray diffraction and FTIR spectroscopy. The dispersion of silicate layers in the polymer matrix was also revealed by transmission electron microscopy (TEM). It was confirmed that the clay was intercalated and exfoliated in the PSAN matrix. The increased thermal stability of PSAN with the addition of clay was observed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The dielectric properties of PSAN were measured in the frequency range 100 Hz to 1 MHz at 35–70°C. It was found that the dielectric constant from the dipole orientation had been suppressed due to the intercalation of clay. The dielectric loss is strongly related to the residual sodium content of clay, which increases as the sodium content increases by the addition of clay. Copyright © 2004 Society of Chemical Industry     

Preparation of nanoclay‐dispersed polystyrene nanofibers via atom transfer radical polymerization and electrospinning

In this study, clay‐dispersed polystyrene (PS) nanocomposites were prepared with the in situ atom transfer radical polymerization method and were subsequently electrospun to form nanofibers 450–650 nm in diameter. The polymer chains extracted from the clay‐dispersed nanofibers exhibited a narrow range of molecular weight distribution. Thermogravimetric analysis (TGA) confirmed a higher thermal stability of the resulting nanocomposites compared to PS. The effect of the weight ratio of montmorillonite on the thermal properties of the nanocomposites was also studied by TGA. Differential scanning calorimetry revealed that the addition of the nanoclay increased the glass‐transition temperature. Moreover, degradation of the bromide chain‐end functionality took place at low temperatures. Scanning electron microscopy showed that the average diameter of the fibers was around 500 nm. The dispersion of clay layers was also evaluated by Al atoms in the PS matrix with the energy‐dispersive X‐ray detection technique. Transmission electron microscopy confirmed the exfoliation of the nanoclay within the matrix. However, the clay layers were oriented along the nanofiber axis. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Comparative study of nanocomposites of polyolefin compatibilizers containing kaolinite and montmorillonite organoclays

This work studied the morphology and physical properties of nanocomposites of different ethylene copolymers and functionalized polyethylenes with two different types of organoclays, to assess the potential application of these fillers as reinforcing components in the design of polyethylene and other polyolefinic based nanocomposites with enhanced properties. A polyethylene‐grafted‐maleic anhydride (PEMA), a poly(ethylene‐co‐acrylic acid), a poly(ethylene‐co‐vinyl acetate), and an ionomer of poly(ethylene‐co‐methacrylic acid) containing a small fraction of polyamide 6 were used to prepare nanocomposites by melt compounding in internal mixer. Two different types of commercial clays were used to obtain nanocomposites with the same organoclay content (5 wt %), i.e., an organomodified montmorillonite and an organomodified kaolinite. The morphology was evaluated by wide angle X‐ray scattering, scanning electron microscopy, transmission electron microscopy, and optical microscopy. The thermal, mechanical and barrier properties were evaluated by differential scanning calorimetry and thermogravimetric analysis, tensile tests and oxygen transmission rate experiments, respectively. From the results, it was seen that PEMA and the ionomer are the best polymer matrices to disperse both organoclays under the conditions applied. Kaolinite and montmorillonite appeared to be dispersed in the nanorange, however, higher aspect ratio was observed for montmorillonite. The best improvements in thermal degradation and in mechanical reinforcement were shown for organomodified kaolinite nanocomposites. But the best improvements in thermo‐oxidative degradation and in oxygen barrier were seen for the nanocomposites with organomodified montmorillonite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of clay with different cation exchange capacity on the morphology and properties of poly(methyl methacrylate)/clay nanocomposites

PMMA/clay nanocomposites were successfully prepared by in situ free‐radical polymerization with the organic modified MMT‐clay using methyl methacrylate monomer and benzoyl peroxide initiator. Two clays with different cation exchange capacity have been used to prepare and compare the several properties. The clays have been modified using Amphoterge K2 by ion exchange reaction to increase the compatibility between the clay and polymer matrices. The modified clays have been characterized by wide‐angle X‐ray diffraction pattern, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA). The powdered X‐ray diffraction and transmission electron microscopy techniques were employed to study the morphology of the PMMA/clay nanocomposites which indicate that the modified clays are dispersed in PMMA matrix to form both exfoliated and intercalated PMMA/modified clay nanocomposites. The thermomechanical properties were examined by TGA, differential scanning calorimetry, and dynamic mechanical analysis. Gas permeability analyzer shows the excellent gas barrier property of the nanocomposites, which is in good agreement with the morphology. The optical property was measured by UV–vis spectroscopy which shows that these materials have good optical clarity and UV resistance. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Synthesis and properties of BCDA‐based polyimide–clay nanocomposites

Bicyclo[2.2.2]oct‐7‐ene‐2,3,5,6‐tetracarboxylic dianhydride (BCDA)‐based polyimide–clay nanocomposites were prepared from their precursor, namely polyamic acid, by a solution‐casting method. The organoclay was prepared by treating sodium montmorillonite (Kunipia F) clay with dodecyltrimethylammonium bromide at 80 °C. Polyamic acid solutions containing various weight percentages of organoclay were prepared from 4,4′‐(4,4′‐isopropylidenediphenyl‐1,1′‐diyldioxy)‐dianiline and BCDA in N‐methyl‐2‐pyrrolidone containing dispersed particles of organoclay at 20 °C. These solutions were cast on a glass plate using a Doctor's blade and then heated subsequently to obtain nanocomposite films. The nanocomposites were characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal mechanical analysis, dynamic mechanical analysis, polarizing microscopy, scanning electron microscopy, transmission electron microscopy, wide‐angle X‐ray diffraction (WAXD) and thermogravimetric analysis. The glass transition temperature of the nanocomposites was found to be higher than that of pristine polymer. The coefficient of thermal expansion of the nanocomposites decreased with increasing organoclay content. WAXD studies indicated that the extent of silicate layer separation in the nanocomposite films depended upon the organoclay content. Tensile strength and modulus of the nanocomposite containing 1% organoclay were significantly higher when compared to pristine polymer and other nanocomposites. The thermal stability of the nanocomposites was found to be higher than that of pristine polymer in air and nitrogen atmosphere. Copyright © 2007 Society of Chemical Industry     

High‐performance polyimide–clay nanocomposite materials based on a dual intercalating agent system

BACKGROUND: Polymer–clay nanocomposites (PCNs) have attracted considerable interest in recent years owing to their unique physical and chemical properties that lead to a wide range of applications. A series of PCN materials consisting of polyimide and layered montmorillonite (MMT) clay were successfully prepared by in situ polymerization. RESULTS: Silicate layers are better dispersed in polymer matrices when dual intercalating agents (hexadecyltrimethylammonium bromide–4,4′‐oxydianiline) are applied for MMT modification according to wide‐angle X‐ray diffraction and transmission electron microscopy studies. Effects of single and dual intercalating agents on thermal stability, mechanical strength and the molecular barrier of PCN materials consisting of organo‐modified MMT were studied by means of thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analyses, gas permeability analysis and vapor permeability analysis. CONCLUSION: Improved thermal and mechanical stabilities, as well as barrier properties were observed for the PCN materials containing dual intercalating agent‐modified MMT. Copyright © 2008 Society of Chemical Industry     

Functional copolymer/organo‐montmorillonite nanoarchitectures. IX. Synthesis and nanostructure–morphology–thermal behaviour relationships of poly[(maleic anhydride)‐alt‐(acrylic acid)]/organo‐ montmorillonite nanocomposites

Functional copolymer/clay hybrids were synthesized by radical‐initiated interlamellar copolymerization of maleic anhydride/maleic acid and acrylic acid with 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride as a water‐soluble ionizable radical initiator in the presence of reactive (octadecylamine‐montmorillonite (ODA‐MMT)) and non‐reactive (dimethyldodecylammonium‐montmorillonite) organoclays at 60 °C in aqueous medium under nitrogen atmosphere. The monomers were dissolved in aqueous medium, and the two types of clay particles used were easily dissolved and dispersed partially swollen, respectively, in deionized water. Structure, thermal behaviour and morphology of the synthesized nanocomposites were investigated using Fourier transform infrared spectroscopy, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and scanning and transmission electron microscopy. It is demonstrated that intercalative copolymerization proceeds via ion exchange between organoclays and carboxylic groups of monomers/polymers, which essentially improves interfacial interactions of polymer matrix and clay layers through strong hydrogen bonding. In the case of intercalative copolymerization in the presence of ODA‐MMT clay, a similar improvement is provided by in situ hydrogen bonding and amidolysis of carboxylic/anhydride groups from copolymer chains with primary amine groups of ODA‐MMT. The nanocomposites exhibit higher degree of intercalation/exfoliation of copolymer chains, improved thermal properties and fine dispersed morphology. Copyright © 2011 Society of Chemical Industry     

Synthesis and properties of polystyrene–montmorillonite nanocomposites by suspension polymerization

Organophilic montmorillonite was prepared using ion‐exchange method between sodium ions in clay layers and stearyltrimethyl ammonium chloride in the various solvents, including deionized water, ethanol, acetone, and toluene. The montmorillonite has the largest d₀₀₁ spacing, as determined by X‐ray diffraction in toluene, than the other solvents considered. Ethanol can completely wash out the overexchanged stearyltrimethyl ammonium chloride among layers of montmorillonite. However, deionized water is the preferred ion‐exchange solvent. The thermal stability of organophilic montmorillonite was investigated by high‐resolution thermogravimetric analysis (TGA). Polystyrene–montmorillonite nanocomposites were obtained by suspension free radical polymerization of styrene in the dispersed organophilic montmorillonite. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) revealed that montmorillonite had been exfoliated. 5.0 wt % of clay in the synthesized nanocomposite was found to be the optimum content that improved both thermal and mechanical properties over those of pure polystyrene under the experimental conditions applied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 101–109, 2004     

Use of a new natural clay to produce poly(methyl methacrylate)‐based nanocomposites

Nanocomposites of poly(methyl methacrylate) (PMMA) filled with 3 wt% of modified natural Algerian clay (AC; montmorillonite type) were prepared by either in situ polymerization of methyl methacrylate initiated by 2,2′‐azobisisobutyronitrile or a melt‐mixing process with preformed PMMA via twin‐screw extrusion. The organo‐modification of the AC montmorillonite was achieved by ion exchange of Na⁺ with octadecyldimethylhydroxyethylammonium bromide. Up to now, this AC montmorillonite has found applications only in the petroleum industry as a rheological additive for drilling muds and in water purification processes; its use as reinforcement in polymer matrices has not been reported yet. The modified clay was characterized using X‐ray diffraction (XRD), which showed an important shift of the interlayer spacing after organo‐modification. The degree of dispersion of the clay in the polymer matrix and the resulting morphology of nanocomposites were evaluated using XRD and transmission electron microscopy. The resulting intercalated PMMA nanocomposites were analysed using thermogravimetric analysis and differential scanning calorimetry. The glass transition temperature of the nanocomposites was not significantly influenced by the presence of the modified clay while the thermal stability was considerably improved compared to unfilled PMMA. This Algerian natural montmorillonite can serve as reinforcing nanofiller for polymer matrices and is of real interest for the fabrication of nanocomposite materials with improved properties. Copyright © 2009 Society of Chemical Industry     

Preparation and properties of polyimide–clay nanocomposite materials for anticorrosion application

A series of polymer–clay nanocomposite (PCN) materials that consist of organosoluble polyimide and layered montmorillonite clay were prepared by the solution dispersion technique. The organosoluble polyimide containing non‐coplanar moiety in diamine monomer and flexible bridging linkages in dianhydride monomer was synthesized by chemical imidization. The as‐synthesized PCN materials were characterized by infrared spectroscopy, wide‐angle powder X‐ray diffraction, and transmission electron microscopy. The organosoluble polyimide showed better corrosion resistance compared to polyaniline, poly(o‐ethoxyaniline) and poly(methyl methacrylate) by using a series of standard electrochemical corrosion measurements of corrosion potential, polarization resistance, and corrosion current in 5 wt % aqueous NaCl electrolyte. Polyimide–clay nanocomposite materials incorporated with low loading of clay were found to further improve corrosion inhibition over pure polyimide. Effects of the material composition on the O₂/H₂O molecular permeability, optical clarity, and thermal properties of polyimide–clay nanocomposite materials were studied by molecular permeability analysis, UV–visible transmission spectra, thermogravimetric analysis, and differential scanning calorimetry, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3573–3582, 2004     

New poly(phenylene oxide)/polystyrene blend nanocomposites with clay: Intercalation,thermal and mechanical properties

We present the first study and results on the preparation and characterization of montmorillonite clay filler based polymer blend nanocomposites of the miscible poly(phenylene oxide)/polystyrene blend. Intercalated nanocomposites, prepared by a melt‐processing method with 2–6 wt % commercially available organically modified sodium montmorillonite, have been characterized with wide‐angle X‐ray diffraction, transmission electron microscopy analysis, thermal analysis (thermogravimetric analysis and differential scanning calorimetry), and mechanical tensile tests. We show that nanocomposites can be successfully prepared in a batch mixer at temperatures much below the conditions conventionally used for this blend without organic degradation. Thermal stability is enhanced by nanoscale hybrid formation. The level of intercalation (change in the d‐spacing) does not change with the clay loading. Better dispersion of clay in the blend matrix has been observed at a low level of clay content. The nanocomposites show improved tensile modulus (by 31%) in comparison to the blend, whereas the tensile strength (stress at break) and elongation decrease in the presence of the filler with an increase in the clay loading. The Halpin–Tsai model is able to predict the modulus of the nanocomposites in very good agreement with the experimental data. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Comparative studies of the properties of poly(methyl methacrylate)–clay nanocomposite materials prepared by in situ emulsion polymerization and solution dispersion

A series of polymer–clay nanocomposite (PCN) materials consisting of organic poly(methyl methacrylate) (PMMA) and inorganic montmorillonite (MMT) clay platelets were prepared successfully by the effective dispersion of nanolayers of the MMT clay in the PMMA framework through both in situ emulsion polymerization and solution dispersion. The as‐prepared PCN materials obtained with both approaches were subsequently characterized with wide‐angle powder X‐ray diffraction and transmission electron microscopy. For a comparison of the anticorrosion performance, a PCN material (e.g., 3 wt % clay loading) prepared by in situ emulsion polymerization, showing better dispersion of the clay platelets in the polymer matrix, exhibited better corrosion protection in the form of a coating on a cold‐rolled steel coupon than that prepared by solution dispersion, which showed a poor dispersion of the clay nanolayers according to a series of electrochemical corrosion measurements. Comparative studies of the optical clarity, molecular barrier properties, and thermal stability of samples prepared in both ways, as membranes and fine powders, were also performed with ultraviolet–visible transmission spectroscopy, molecular permeability analysis, thermogravimetric analysis, and differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1936–1946, 2004     

Elucidation of the nanoparticle effect on the grafting of vinyl monomers onto cotton fabric

The grafting emulsion polymerization of vinyl monomers onto cotton was carried out in the presence of double‐modified montmorillonite clay. The obtained results show that grafting with glycidyl methacrylate/montmorillonite gave a higher rate of grafting than grafting with methyl methacrylate/montmorillonite in all clay percentages, and also, the grafting yield of glycidyl methacrylate monomer onto cotton in the presence of montmorillonite clay had a higher value than that in the absence of the clay for all factors studied. Cotton grafted with glycidyl methacrylate/montmorillonite with a graft yield of about 50% was prepared according to the emulsion polymerization technique and was treated with different concentrations of dibutylamine solutions ranging from 1 to 4%. The obtained samples were characterized according to nitrogen content, thermal stability, scanning electron microscopy, mechanical properties, water absorption, and color strength according to acid, basic, and reactive dyes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A new application of biosurfactant for the preparation of polycaprolactone/layered silicate nanocomposites

In this study, by using the biosurfactant as the clay modifier, one first attempted to prepare polycaprolactone (PCL)/montmorillonite nanocomposites via a melt‐blending method. The production of biosurfactant (surfactin) and the modification of clay proceeded simultaneously by the incubation of Bacillus subtilis CWS1. The evidence for the formation of intercalated/exfoliated nanocomposites was assessed by X‐ray diffraction spectroscopy, scanning electron microscopy, and transmission electron microscopy observations. The conclusions were also supported by the result of dynamic mechanical thermal analysis, thermogravimetric analyzer, and differential scanning calorimetry. As a result, the modified clay can be well dispersed into the PCL matrix in nanoscale sizes, because the biosurfactant is partially compatible with PCL chains intercalating into clay layers. As for mechanical properties, a marked increase in tensile strength and Young's modulus can be observed when the biosurfactant‐pretreated clay was used to replace the neat clay for the preparation of nanocomposites. Based on the considerations of thermal and mechanical properties, it was also found that 10 wt% of clay content was optimal for the preparation of nanocomposite. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Comparison of the influence of different compatibilizers on the structure and properties of ethylene vinyl acetate copolymer/modified clay nanocomposites

Nanocomposites of an ethylene vinyl acetate copolymer and clay were prepared by melt blending and extrusion. Two different compatibilizers, ethylene glycidyl methacrylate (EGMA) and maleic anhydride grafted polypropylene (MAPP), were used in these nanocomposites. The structural properties of the composites were characterized with X‐ray diffraction and transmission electron microscopy. The surface morphology was characterized with polarized optical microscopy. The tensile and permeability properties were studied. The thermal stability of the nanocomposites was characterized through thermogravimetric analysis. MAPP‐compatibilized nanocomposites had intercalated and partially exfoliated structures, whereas EGMA‐compatibilized nanocomposites had completely exfoliated structures. The EGMA‐compatibilized nanocomposites were thermally more stable than the MAPP‐compatibilized nanocomposites. The mechanical and permeability properties of the EGMA‐compatibilized nanocomposites were better than those of the MAPP‐compatibilized nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Bio‐based polymer nanocomposites based on layered silicates having a reactive and renewable intercalant

Soybean oil‐based polymer nanocomposites were synthesized from acrylated epoxidized soybean oil (AESO) combined with styrene monomer and montmorillonite (MMT) clay by using in situ free radical polymerization reaction. Special attention was paid to the modification of MMT clay, which was carried out by methacryl‐functionalized and quaternized derivative of methyl oleate intercalant. It was synthesized from olive oil triglyceride, as a renewable intercalant. The resultant nanocomposites were characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The effect of increased nanofiller loading in thermal and mechanical properties of the nanocomposites was investigated by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The nanocomposites exhibited improved thermal and dynamic mechanical properties compared with neat acrylated epoxidized soybean oil based polymer matrix. The desired exfoliated nanocomposite structure was achieved when the OrgMMT loading was 1 and 2 wt % whereas partially exfoliated nanocomposite was obtained in 3 wt % loading. It was found that about 400 and 500% increments in storage modulus at glass transition and rubbery regions, respectively were achieved at 2 wt % clay loading compared to neat polymer matrix while the lowest thermal degradation rate was gained by introducing 3 wt % clay loading. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2031–2041, 2013     

Preparation and characterization of poly(butylene terephthalate) nanocomposites with various organoclays

Layered‐silicate‐based polymer–clay nanocomposite materials were prepared depending on the surface modification of montmorillonite (MMT). Nanocomposites consisting of poly(butylene terephthalate) (PBT) as a matrix and dispersed inorganic clay modified with cetyl pyridinium chloride (CPC), benzyl dimethyl N‐hexadecyl ammonium chloride, and hexadecyl trimethyl ammonium bromide by direct melt intercalation were studied. The organoclay loading was varied from 1 to 5 wt %. The organoclays were characterized with X‐ray diffraction (XRD) to compute the crystallographic spacing and with thermogravimetric analysis to study the thermal stability. Detailed investigations of the mechanical and thermal properties as well as a dispersion study by XRD of the PBT/clay nanocomposites were conducted. X‐ray scattering showed that the layers of organoclay were intercalated with intercalating agents. According to the results of a differential scanning calorimetry analysis, clay acted as a nucleating agent, affecting the crystallization. The PBT nanocomposites containing clay treated with CPC showed good mechanical properties because of intercalation into the polymer matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of hybrid clay/poly (N,N‐dimethylaminoethyl methacrylate) nanocomposites

Four quaternary ammonium salt monomers (2a–d) were synthesized from N,N‐dimethylaminoethyl methacrylate and subsequently polymerized to afford cationic polymers (3a–d). The synthesized monomers and polymers were characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopy. Molecular weights of the synthesized polymers were determined using gel permeation chromatography. Polymer/clay nanocomposites (4a–d) were prepared using solution‐intercalation method and characterized by FTIR, X‐ray diffraction, high‐resolution transmission electron microscopy, energy dispersive X‐ray, and thermogravimetric analysis. Data analysis showed that polymer/clay nanocomposites have intercalated structure. The dielectric properties of the polymer/clay nanocomposites were studied as a function of both temperature and frequency. POLYM. COMPOS., 37:2950–2959, 2016. © 2015 Society of Plastics Engineers