PVC/montmorillonite nanocomposites based on a thermally stable,rigid‐rod aromatic amine modifier

Two kinds of polyvinyl chloride (PVC)/montmorillonite (MMT) nanocomposites were prepared by the melt intercalation method based on a thermally stable, rigid‐rod aromatic amine modifier and a commonly used 1‐hexadecylamine. The information on morphological structure of PVC/MMT nanocomposites was obtained using XRD and TEM. The mechanical, thermal, and flame retardant properties of the nanocomposites were characterized by universal tester, DMA, TGA, and cone calorimeter. The degree of degradation of PVC was studied by ¹H‐NMR. MMT treated by the aromatic amine exhibited better dispersibility than that treated by 1‐hexadecylamine. The nanocomposites, based on this MMT, consequently exhibited better mechanical, thermal, and flame retardant properties and lower degradation degree than those based on 1‐hexadecylamine‐treated MMT. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 567–575, 2004     

Poly(etherimide)/montmorillonite nanocomposites prepared by melt intercalation

A novel aromatic amine organo‐modifier synthesized in our previous work was used to treat montmorillonite (MMT) and the organo‐modified MMT was used to prepare poly(etherimide) (PEI)/MMT nanocomposites by a melt intercalation method. MMT treated by this amine exhibited large layer‐to‐layer spacing and a high ion‐exchange ratio (>95%). The nanocomposites were characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM), dynamic mechanical analysis, a universal tester, thermogravimetric analysis, and by differential scanning calorimetry. The results of XRD and TEM showed that the nanocomposites formed exfoliated structures even when the MMT content was 10 wt %. When the MMT content was below 3 wt %, the PEI/MMT nanocomposites were strengthened and toughened at the same time. The nanocomposites also showed marked decreases in coefficient of thermal expansion and solvent uptake. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1857–1863, 2003     

Use of acrylic based surfmers for the preparation of exfoliated polystyrene–clay nanocomposites

Two polymerizable cationic surfactants, (11-acryloyloxyundecyl)dimethyl(2-hydroxyethyl)ammonium bromide (hydroxyethyl surfmer) and (11-acryloyloxyundecyl)dimethylethylammonium bromide (ethyl surfmer), were used for the modification of montmorillonite (MMT) clay. The modification of MMT dispersions was carried out by ion exchange of the sodium ions in Na⁺-MMT by surfactants in aqueous media. Modified MMT clays were then dispersed in styrene and subsequently polymerized in bulk by a free-radical polymerization reaction to yield polystyrene–clay nanocomposites. An exfoliated structure was obtained using the ethyl surfmer-modified clay, whereas a mixed exfoliated/intercalated structure was obtained using the hydroxyethyl surfmer-modified clay. Nanocomposite structures were confirmed by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The nanocomposites exhibited enhanced thermal stability and an increase in glass transition temperature, relative to neat polystyrene. The nanocomposites also exhibited enhanced mechanical properties, which were dependent on the clay loading. Intercalated polystyrene–clay nanocomposites were obtained using the non-polymerizable surfactant-modified clay (cetyltrimethylammonium bromide). Nanocomposites made from mixtures of surfmer-modified and CTAB-modified clays were also prepared, showing intermediate properties. However, when the nanocomposites were prepared in solution only intercalated morphologies were obtained. This was attributed to the competition between the solvent molecules and monomer in penetrating into clay galleries. These nanocomposites also exhibited enhanced thermal stability relative to the virgin polystyrene prepared by the same method. Similar temperatures of degradation (at 50% decomposition) were found for these nanocomposites relative to those prepared by bulk polymerization.     

Synthesis and rheological properties of oligoimide/montmorillonite nanocomposites

We report a facile strategy for preparing polyimides (PI)/montmorillonite (MMT) nanocomposites at moderate temperatures that avoids thermal degradation of organically-modified MMT (organo-MMT) that is commonly observed during conventional melt-blending of organo-MMT with commercial high molecular weight PI at elevated temperatures. Novel polyimides of low molecular weight (oligoimides) based on 1,3-bis(3′,4,-dicarboxyphenoxy)benzene and 4,4′ bis(4″-aminophenoxy)diphenylsulfone were synthesized and subsequently melt-blended at temperatures ranging from 150 to 250 °C with special organically-modified montmorillonite clay nanoparticles to form new polyimide/organo-MMT nanocomposites with special combination of physical and chemical properties for diverse applications such as microelectronic components where chemical inertness, high temperature stability, low dielectric constant, mechanical toughness and processability are primary requirements. It was found that application of a strong shearing flow near the glass transition temperature of the oligoimide to the oligoimide/organo-MMT nanocomposite melt blend containing 6±2 vol% of the organo-MMT resulted in three orders of magnitude increase in the viscosity. Partial exfoliation of the organo-MMT together with constrained deformation of the polymer between the rigid nanoparticle layers (as evidenced by formation of the network structure or fractal gel) are thought to be responsible for this observed viscosity behavior. The viscosity behavior is typical for model xylene/MMT system where the MMT particles were dispersed in xylene solvent homogeneously via ultrasonic mixing. This study suggests that the rheological methods used here may provide a valuable analytical tool to accelerate efforts to develop useful polyimide nanocomposites from synthetic oligoimides containing ceramic nanoparticles having different shapes and sizes. Further, because of their facile synthesis and desirable characteristics these polyimide/MMT clay nanocomposites are expected to be excellent model systems for exploring feasibility of new routes for driving organic polymers to self-assemble into useful nanocomposites.     

Effect of oligomeric‐modified montmorillonite on morphology and properties of polycarbonate/montmorillonite nanocomposites

Low‐molecular‐weight copolymers of styrene and vinylbenzyl ammonium salts (oligomeric surfactant) were used to modify montmorillonite (MMT). The oligomeric‐modified MMT showed good thermal stability, which made it suitable to be used for preparing polycarbonate(PC)/MMT nanocomposites at high temperature. A different series of PC/MMT nanocomposites had been prepared by melt processing using a twin screw extruder. The effect of oligomeric surfactant structure and clay loading on the morphology, mechanical property, thermal stability, and color appearance of the nanocomposites were explored. The results of X‐ray diffraction and transmission electron microscopy analyses indicated that the PC/MMT nanocomposites had partially exfoliated structures. The PC/MMT nanocomposites were found to retain light colored, which was important for optical application. Compared to neat PC, the nanocomposites showed better properties of thermal stability and heat insulation. The mechanical properties of the nanocomposites are significantly enhanced by incorporating clay into the PC matrix. The tensile strength of nanocomposites with 2 wt% clay content was up to 55 MPa, which was much higher than that of the neat PC (37 MPa). The maximum tensile modulus value was 19% higher than that of neat PC. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

PMMA/o‐MMT nanocomposites obtained using thermally stable surfactants

In the preparation of polymer/montmorillonite (MMT) nanocomposites, the commonly used compatibilizers (cations of long carbon‐chain alkyl ammonium salts) present the drawback of a poor thermal stability. During bulk processing of nanocomposites elevated temperatures are usually required and, if processing temperature is close to decomposition temperature of the surfactant, decomposition will occur altering the interface between filler and polymer. To solve this problem, organically modified MMTs with thermally stable imidazolium surfactants have been prepared. A series of nanocomposites were obtained by dispersing o‐MMT in poly(methyl methacryate) (PMMA) matrix via an in situ free radical polymerization. The nanocomposites were characterized by X‐ray diffraction, transmission electron microscopy, gel permeation chromatography, thermogravimetric analysis, dynamic mechanical analysis, and nanoindentation measurements. The results showed that nanocomposite thermal stability depended on both the kind of used surfactant and degree of exfoliation. Under the same values of molecular weight, the nanocomposites containing imidazolium cations showed a better thermal stability with respect to the nanocomposite obtained using a standard alkylammonium surfactant. Dynamic mechanical and Nanoindentation measurements showed an improvement of mechanical properties, such as modulus and hardness, with respect to pure PMMA. Solution blending treatments on these nanocomposites led to obtaining of further improvement of the thermal performance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41393.     

Synthesis and properties of polyimide (containing naphthalene) nanocomposites with organo‐modified montmorillonites

2,7‐Bis(4‐aminophenoxy) naphthalene (BAPN), a naphthalene‐containing diamine, was synthesized and polymerized with a 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) to obtain a polyimide (PI) via thermal imidization. To enhance the thermal and mechanical properties of the polymer, PI–Montmorillonite (MMT) nanocomposites were prepared from a DMAc solution of poly(amic acid) and a DMAc dispersion of MMT, which were organo‐modified with various amounts of n‐dodecylamine (DOA) or cetylpyridium chloride (CPC). FTIR, XRD, and TEM (transmission electron microscopy) were used to verify the incorporation of the modifying agents into the clay structure and the intercalation of the organoclay into the PI matrix. Results demonstrated that the introduction of a small amount of MMT (up to 5%) led to the improvement in thermal stability and mechanical properties of PI. The decomposition temperature of 5% weight loss (T_d,5%) in N₂ was increased by 46 and 36°C in comparison with pristine PI for the organoclay content of 5% with DOA and CPC, respectively. The nanocomposites were simultaneously strengthened and toughened. The dielectric constant, CTE, and water absorption were decreased. However, at higher organoclay contents (5–10%), these properties were reduced because the organoclay was poorly dispersed and resulted in aggregate formation. The effects of different organo‐modifiers on the properties of PI–MMT nanocomposite were also studied; the results showed that DOA was comparable with CPC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Polybenzoxazine/clay hybrid nanocomposites: influence of preparation method on the curing behavior and properties of polybenzoxazines

Several types of polybenzoxazine/clay hybrid nanocomposites have been prepared from organically modified montmorillonite (OMMT) and mono- or bifunctional benzoxazine, 3-phenyl-3,4-dihydro-2H-1,3-benzoxazine (Pa) or bis(3-phenyl-3,4-dihydro-2H-1,3-benzoxazinyl) isopropane (Ba), respectively. OMMT was prepared by a cation exchange of montmorillonite (MMT) with ammonium salts of amines such as tyramine, phenylethylamine, aminolauric acid, and dodecyl amine. Polybenzoxazine/clay nanocomposites were prepared by two different methods, namely melt method and solvent method. Melt method employs the blending of benzoxazine and OMMT above the melting point of benzoxazine without solvent. In the solvent method, OMMT was dispersed in an organic solvent and then blended with benzoxazine. XRD measurements of the polybenzoxazine/clay hybrid nanocomposites showed that the blending method and the kind of solvent play crucial roles in the dispersion of OMMT in the polybenzoxazine matrix. DSC showed that the inclusion of any type of OMMT significantly lowered the curing exotherm of benzoxazines. The hybrid nanocomposites exhibited higher T_g values than the pristine resins. Dynamic and isothermal TGA clearly showed that the thermal stability was improved by the inclusion of clay.     

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     

The effects of metallic derivatives released from montmorillonite on the thermal stability of poly(ethylene terephthalate)/montmorillonite nanocomposites

By in situ polycondensation, poly(ethylene terephthalate) (PET)/montmorillonite (MMT) nanocomposites was prepared, which were characterized via X‐ray diffraction and transmission electron microscope. The processing stability of these nanocomposites was investigated by the change of number–average molecular weight and carboxyl terminal group content during injection molding, and the thermal stability of the nanocomposites was investigated via thermogravimetric analysis. It was found that some metallic derivatives released from MMT during polycondensation had a great influence on the processing and thermal stabilities of the nanocomposites. The quantity of these metallic derivatives was determined by inductively coupled plasma. The stabilization effect of phosphorous compounds generated from MMT modified with phosphonium was observed. Processing stability and thermal stability of these nanocomposites exhibited similar trend because of almost the same causes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1692–1699, 2006     

Property enhancement in unsaturated polyester nanocomposites by using a reactive intercalant for clay modification

Polymeric nanocomposites were synthesized from unsaturated polyester (UPE) matrix and montmorillonite (MMT) clay using an in situ free radical polymerization reaction. Organophilic MMT was obtained using a quaternary salt of coco amine as intercalant having a styryl group making it a reactive intercalant. The resultant nanocomposites were characterized via X‐ray diffraction and transmission electron microscopy. The effect of increased nanofiller loading on the thermal and mechanical properties of the nanocomposites was investigated. All the nanocomposites were found to have improved thermal and mechanical properties as compared with neat UPE matrix, resulting from the contribution of nanolayer connected intercalant‐to‐crosslinker which allows a crosslinking reaction. It was found that the partially exfoliated nanocomposite structure with an exfoliation dominant morphology was achieved when the MMT loading was 1 wt %. This nanocomposite exhibited the highest thermal stability, the best dynamic mechanical performance and the highest crosslinking density, most probably due to more homogeneous dispersion and optimum amount of styrene monomer molecules inside and outside the MMT layers at 1 wt % loading. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Study on thermoplastic polyurethane/montmorillonite nanocomposites

The thermoplastic polyurethane/montmorillonite (TPU/MMT) nanocomposites were prepared by melt intercalation. The structure and property of the TPU/MMT nanocomposites were studied by XRD, TEM, TG, Molau test, and mechanical property measurement. The interlayer spacing between the MMT platelets in TPU/MMT nanocomposites blended for 10 and 15 min was the same. The silicate platelets were dispersed in TPU matrix on 5–15 nm scale for TPU/MMT nanocomposites. The interface interaction between the silicate layers and TPU matrix for TPU/MMT nanocomposites was strong. Compared to those of pure TPU, the tensile strength and tear strength of the TPU/MMT nanocomposites increased. The tensile strength and tear strength of the TPU/MMT nanocomposites decreased with increasing blending time because of the degradation of the TPU matrix. The thermal stability of the TPU/MMT nanocomposites was lower than that of the pure TPU in the first step, whereas in the second step, the TPU/MMT nanocomposites showed higher thermal stability. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers     

Enhanced mechanical properties and fire retardancy of polyamide 6 nanocomposites based on interdigitated crystalline montmorillonite–melamine cyanurate

Polyamide 6 (PA6)–montmorillonite (MMT)–melamine cyanurate (MCA) nanocomposites were prepared by the incorporation of interdigitated crystalline MMT–MCA. Their morphologies were assessed by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, thermal stability measurement by thermogravimetric analysis, mechanical properties measurement by tensile tests, and fire retardancy measurement by limiting oxygen index testing and vertical burning testing (UL‐94). The results indicate that MMT–MCA was homogeneously nanodispersed in PA6. Compared with PA6–MCA, the PA6–MMT–MCA nanocomposites showed enhanced thermal stability. The mechanical properties and fire retardancy show that the PA6–MMT–MCA nanocomposites with 5 wt % total loading of MMT–MCA reached UL‐94 V‐2 rating (3.2 mm) and significantly increased the tensile strength of PA6 up to 24.8 % with only 1 wt % MMT in PA6. Through the control the weight ratio of MMT and MCA in MMT–MCA, the Young's modulus of PA6 could be adjusted in a very wide range (300–1100 MPa) because of the dual role of the rigid MMT and nonrigid MCA layers. The reinforced mechanism of the mechanical properties was also investigated. Consequently, the PA6–MMT–MCA nanocomposites with a good nanodispersing ability, improved thermal stability, excellent mechanical properties, and good flame retardancy were obtained and could provide broad prospects for wider applications for PA6 materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46039.     

Dynamic mechanical,thermal, and morphological properties of silane‐treated montmorillonite reinforced polycarbonate nanocomposites

Three different loading of 3‐aminopropyltriethoxysilane (APS) was used to modify the Na‐montmorillonite via cation exchange technique. The Na‐MMT and silane‐treated montmorillonite (STMMT) were melt‐compounded with polycarbonate (PC) by using Haake Minilab machine. The PC nanocomposite samples were prepared by using Haake Minijet injection molding technique. The intercalation and exfoliation of the PC/MMT nanocomposites were characterized by using X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The thermal properties of the PC nanocomposites were investigated by using dynamic mechanical analyzer and thermogravimetry analyzer. XRD and TEM results revealed partial intercalation and exfoliation of STMMT in PC matrix. Increase of APS concentration significantly enhanced the storage modulus (E′) and improved the thermal stability of PC nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermal stability,aging properties,and flame resistance of NR‐based nanocomposite

Polymer/clay nanocomposites have some unique properties due to combination of flame resistance and improved mechanical and thermal stability properties which are important to enhance the material quality and performance. The objective of this work was to investigate the effect of organically modified montmorillonite (org‐MMT) on the thermal and flame retardant as well as hardness and mechanical properties of the nanocomposites based on the natural rubber (NR). It was shown that by the addition of 3 wt % of org‐MMT to NR, its aging hardness rise was decreased more than 55% and the ignition time was delayed about 150%. The reduction in heat release rate peak value was equal to 54% compared to the pristine NR. Addition of org‐MMT improved the thermal stability of the NR. Furthermore, nanocomposites which were calendared before curing showed much more thermal stability and fire resistance than those which contained similar amount of organoclay. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and characterization of polyimide/modified layered double hydroxide nanocomposites

Polyimide (PI)/modified layered double hydroxide (m‐LDH) nanocomposites were prepared in this study. For this work, m‐LDHs were prepared from layered double hydroxides (LDHs) through an anionic exchange reaction with pyromellitic dianhydride (PMDA), succinic acid or terephthalic acid. PMDA and 4,4′‐oxydianiline were used to make the poly(amic acid) precursor for PI. X‐ray diffraction and transmission electron microscopy measurements confirmed that the PMDA‐modified LDH (PMH) and terephthalic acid‐modified LDH (TMH) were well dispersed in the PI matrix. For the succinic acid‐modified LDH, some of the LDH was intercalated with the succinic acid molecules but most maintained its original structure. Thus, the PI/PMH and PI/TMH nanocomposites exhibited improved mechanical, thermal and electrical properties compared to pure PI. The PMH has aromatic groups and is expected to have better π–π interactions with the PI chains than the other m‐LDHs. Thus, the PI/PMH nanocomposites exhibited the best properties among the nanocomposites investigated. Copyright © 2010 Society of Chemical Industry     

Morphology,Thermal and Mechanical Properties of Poly (Styrene-Acrylonitrile) (SAN)/Clay Nanocomposites from Organic-Modified Montmorillonite

Poly (styrene-acrylonitrile) (SAN)/clay nanocomposites have successfully been prepared by melt intercalation method. The hexadecyl triphenyl phosphonium bromide (P16) and cetyl pyridium chloride (CPC) are used to modify the montmorillonite (MMT). The structure and thermal stability property of the organic modified MMT are, respectively characterized by Fourier transfer infrared (FT-IR) spectra, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results indicate that the cationic surfactants intercalate into the gallery of MMT and the organic-modified MMT by P16 and CPC has higher thermal stability than hexadecyl trimethyl ammonium bromide (C16) modified MMT. The influences of the different organic modified MMT on the structure and properties of the SAN/clay nanocomposites are investigated by XRD, transmission electronic microscopy (TEM), high-resolution electron microscopy (HREM), TGA and dynamic mechanical analysis (DMA), respectively. The results indicate that the SAN cannot intercalate into the interlayers of the pristine MMT and results in microcomposites. However, the dispersion of the organic-modified MMT in the SAN is rather facile and the SAN nanocomposites reveal an intermediate morphology, an intercalated structure with some exfoliation and the presence of small tactoids. The thermal stability and the char residue at 700°C of the SAN/clay nanocomposites have remarkably enhancements compared with pure SAN. DMA measurements show that the silicate clays improve the storage modulus and glass transition temperature (Tg) of the SAN matrix in the nanocomposites.     

Polypropylene/organically modified Sabah montmorillonite nanocomposites: Surface modification and nanocomposites characterization

The aim of the work is to extract, purify, and organically modify montmorillonite (MMT) of Lahad Datu, Sabah bentonite. The octadecylamine treated Sabah MMT (S‐OMMT) (2–8 wt%) was then melt blended with polypropylene (PP) and maleated polypropylene (PPgMAH) (10 wt%) via single screw nanomixer extruder followed by injection molding into test samples to examine the mechanical, thermal, and morphological properties of PP/S‐OMMT nanocomposites. Unmodified Sabah MMT (S‐MMT) and commercial grade MMT (Nanomer 1.30P) filled PP nanocomposites were also characterized for comparison purpose. X‐ray diffraction results showed that the interlayer spacing of S‐MMT increased after organic modification as Fourier transform infra‐red and elemental analysis evidenced the presence of octadecylamine. PP/S‐OMMT nanocomposites showed a better dispersion and strength compared to PP/Nanomer 1.30P nanocomposites due to its smaller MMT platelet size. differential scanning calorimetry and Thermogravimetry analysis revealed that the thermal stability and crystallinity of neat PP improved with the addition of all types of MMT. Dynamic mechanical analyzer showed that PP nanocomposites have higher storage modulus (E′) values than the neat PP over the whole temperature range. The new PP/S‐OMMT nanocomposites showed a comparable performance with PP/Nanomer 1.30P nanocomposites exhibiting promising future applications of S‐MMT in polymer/MMT nanocomposites. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Preparation and properties of montmorillonite‐based polyimide nanocomposites

Montmorillonite (MMT)‐based polyimide (PI) nanocomposites were prepared via two‐stage polymerization of PI using polyamic acid (PAA). The clay was organically modified using various alkylammonium ions to examine the effect of changes in alkyl length on the intercalation spacing of both the treated clays and their hybrids with PAA and PI. The intercalation behavior of clay in the PI matrix and its thermal and mechanical properties were investigated as a function of clay concentration. The d‐spacing of organically modified MMT (O‐MMT) increased with increasing length of the alkylammonium chain. PI/O‐MMT hybrids form exfoliated nanocomposites at clay concentrations below 2 wt%, while they form intercalated nanocomposites together with some exfoliated ones at clay contents exceeding 4 wt%. Young's modulus increased rapidly to a clay loading of 2 wt%, and leveled off with further increases in clay loading. The tensile strength at break increased rapidly up to a clay loading of 1 wt%, and then decreased sharply, while the strain at break showed a monotonic decrease with increasing clay loading from 0 to 8 wt%. The storage modulus, E′, in the temperature range below the glass transition temperature T_g, generally increased with increasing clay content, except at the highest clay content of 8 wt%. Copyright © 2004 Society of Chemical Industry     

Structure and properties of nanocomposites prepared by directly melt blending ethylene‐co‐vinylacetate and natural montmorillonite

The poly(ethylene‐co‐vinylacetate)/montmorillonite (EVA/MMT) nanocomposites were prepared by directly melt blending EVA and natural MMT in the presence of hexadecyl trimethylammonium bromide. The interlayer spacing of the silicate layers in EVA/MMT nanocomposites increased within 15 min of the blending time, and then remained unchanged with further increase in the blending time. The tensile and tear strength and Young's modulus of EVA/MMT nanocomposites increased with increasing blending time and reached the maximum value at 15 min, and then decreased. The tensile and tear strength and Young's modulus of EVA/MMT nanocomposites blended at 140°C were lower than those of the nanocomposites blended at 120°C. The thermal stability of EVA/MMT nanocomposites was improved compared with EVA. Furthermore, the thermal stability of EVA/MMT nanocomposites in nitrogen was higher than thermal stability of the nanocomposites in air because of the air destabilized the EVA and speeded up both deacylation and degradation. POLYM. COMPOS., 27:529–532, 2006. © 2006 Society of Plastics Engineers