Presence Of Layered Double Hydroxides Research Articles

Interactions between antibiotic removal, water matrix characteristics and layered double hydroxide sorbent material

Sorption by layered double hydroxides (LDH) is gaining substantial interest for remediating emerging contaminants, including pharmaceuticals from wastewaters. Findings from a sorbent material performing successfully in lab-based studies using non-environmental (laboratory-sourced) water cannot be assumed to translate to equal performance under environmental downstream applications. However, studies evaluating sorbent material performance for removal of pollutants and understanding material interactions with environmental waters are limited. This study evaluates the removal of the antibiotic amoxicillin (AMX) using a Mg2Al–NO3-LDH sorbent material from laboratory-grade water and wastewater effluent (WWE). AMX is successfully removed (94.53 ± 4.30 % within 24 h) in laboratory-grade water (under batch sorption conditions: 100 μg/L AMX, 0.2 g/L LDH, 20 °C). The comparison of LDH removal performance in laboratory grade and WWE shows a decreased maximum removal of AMX in WWE (13.39 ± 5.53 %). A lower final AMX concentration is observed in the WWE without the presence of LDH, compared to the ‘removal’ experiments in WWE with the presence of LDH, indicating a contribution of non-sorption removal pathways of AMX. This is proposed to be due to the difference in metal concentrations in the WWE with and without LDH present. The presence of LDH is found to decrease concentrations of metal pollutants in WWE, such as Zn concentration decreasing by 85 % over 24 h, changing water characteristics. Overall, this paper reports that an LDH performs differently in laboratory-sourced water and a wastewater effluent. This provides evidence that sorbent material performance needs to be evaluated in complex water matrices to ensure that it is representative of how a sorbent material will perform in an environmental application, which is the end goal of developing such technologies. Finally, good practice recommendations are provided for future lab-scale sorption experiments evaluating the performance of any new sorbent materials for water treatment applications.

Effect of ZnAl-NO2 LDH on chloride entrapment and protection of iron reinforcement in mortar samples

Layered double hydroxides (LDHs) have gained attention in the concrete research field, appearing as prospective additives for controlling chloride attack, and as micro or nano deliverers of corrosion inhibitors. This work reports the effect of ZnAl-NO2 LDH on the evolution of chloride concentration in the pore solution and on the corrosion resistance of iron in mortar samples exposed to 3.5 % NaCl solution. To this end, Ag/AgCl sensors were used to monitor the ingress of chloride ions into mortar, while the electrochemical state of the iron was evaluated by electrochemical impedance spectroscopy. Furthermore, the mortars were analyzed by XRD and TGA, and the total amount of chloride was measured with a commercial sensor. Mortars with LDH showed a slower increase of chloride ions in the pore solution and the preservation of the passive state of the Fe. The presence of LDHs did not cause a significant structural change in the mortars, which was evidenced by the similar distribution of the high frequency resistance as a function of depth in the samples with and without the additive. Finally, the amount of bound chloride in the cementitious material was higher in the LDH-containing mortars. In conclusion, ZnAl-NO2 LDH exhibited a positive effect on the protection of reinforcement embedded in mortar samples when subjected to chloride ingress.

The Inhibitive Effect of Sebacate-Modified LDH on Concrete Steel Reinforcement Corrosion

In recent decades, layered double hydroxides (LDH) have been proposed as innovative corrosion inhibitors for reinforced concrete. Their protective action is based on the ability to intercalate specific anions in the interlayer and on their ability to exchange the intercalated anion. In the present study, an organically charged LDH, with sebacate anions in the interlayer (LDH-S), is proposed as a water-repellent additive for mortar. The waterproofing efficiency of LDH-S and the associated corrosion inhibition ability has been evaluated in reinforced mortar samples. A 42% decrease in the water capillary absorption coefficient has been estimated when 3% LHD-S is added to a mortar. Both the passivation processes of the steel rebars during the curing period and the initiation of corrosion due to chloride exposure have been studied by electrochemical measurements. Three different mortars have been evaluated: reference mortar (REF), mortar with Mg-Al LDH (LDH), and mortar with LDH-sebacate (LDH-S). The latter has shown an important protective capacity for preventing the initiation of corrosion by chloride penetration, with an inhibitory efficiency of 74%. The presence of LDHs without sebacate in the interlayer also improved the performance of the mortar against rebar corrosion, but with lower efficiency (23% inhibitory efficiency). However, this protection is lost after continued chloride exposure over time, and corrosion initiates similarly to the reference mortar. The low corrosion current density values registered when LDH-S is added to the mortar may be related to the increased electrical resistance recorded in this mortar.

Preparation and evaluation of Ca/Mg-layered double hydroxide as a novel modifier for electrochemical determination of gibberellic acid

We report that Ca/Mg-layered double hydroxides (LDHs) were synthesized with the microwave-assisted co-precipitation method successfully. Ca/Mg-LDHs were used as new nanocomposites based on a glassy carbon electrode (GCE) for the determination of gibberellic acid (GA3). The electrochemical sensors were evaluated with Ca/Mg-layered double hydroxide (Ca/Mg-LDH) as a novel modifier. The high potential of the modified electrode to determine the low values of GA3 was studied by using DPV pulsed differential approach. Layered double hydroxides (LDHs) due to their unique and excellent physicochemical properties can be used in sensors based on glassy carbon electrode (GCE). The presence of LDHs in GCE improve the ratio of surface to volume and can increase accuracy and decrease the detection of limit. The final products were characterized by Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), Thermogravimetry (TG) and differential scanning calorimetry (DSC). The results showed that the LDH/GCE electrochemical sensor has good sensitivity for the determination of GA3 at a concentration range of 0.029 up to 0.297 mM, with the detection of limit about 0.009 mM.

Facile preparation of layered double hydroxide (LDH)-alginate beads as sustainable system for the triggered release of diclofenac: Effect of pH and temperature on release rate

This paper concerns the facile preparation of alginate beads encapsulating layered double hydroxide (LDH) intercalated with diclofenac sodium as drug delivery systems. To better evaluate the effect of LDH carrier, alginate beads loaded with free diclofenac were also prepared. Composites hydrogel beads were ionotropically crosslinked in CaCl2 solution at 4 °C. Thermal and barrier properties were evaluated and correlated with the presence of the inorganic phase. Swelling behavior was investigated over time. Release kinetics of diclofenac at different pH and temperatures were evaluated. The diclofenac release behavior appeared to be affected by the presence of LDH, the pH of release medium and the temperature allowing for fabricating a sustainable composite characterized by a triggered drug release rate. Finally, empirical relationships correlating the drug diffusion as a function of temperature and pH were extrapolated.

Bioinspired Reactive Interfaces Based on Layered Double Hydroxides-Zn Rich Hydroxyapatite with Antibacterial Activity

This work is focused on the preparation and multi-technique characterization of potentially biocompatible reactive interfaces obtained by combining layered double hydroxides (LDHs) and hydroxyapatite (HA). Antimicrobial and osteoinductive metallic ions as Zn2+ and Ga3+ were chosen as intralayer constituents of LDH to obtain ZnAl and ZnAlGa systems. These LDHs, exchanged with dihydrogenphosphate anions, promoted the precipitation of HA on the LDH surface yielding HA@LDH composites. X-ray diffraction quantitative analysis, through the Rietveld refinement method, coupled with elemental analysis and micro-Raman spectroscopy showed the formation of a mixed Ca-Zn HA phase. Scanning electron microscopy revealed that HA, in the presence of LDH, grew preferentially along its a-axis, thus crystallizing mainly in the form of flake crystals. LDH and HA@LDH composites showed antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa at not cytotoxic concentrations for human osteoblasts (hFob 1.19), especially when Ga cations were present in the LDH structure. The effect of the presence of HA in the composites on the bone-bonding ability and on human osteoblast proliferation was also investigated. The HA seemed to reduce the toxicity of the LDH toward human osteoblast while did not affect the bone-bonding ability. This multidisciplinary study provides the bio-chemical, structural characterization of new LDH and HA@LDH composites, evaluating also their bioactivity to be potentially applicable to titanium-based prostheses.

Propylene Oxide Polymerization in the Presence of Layered Double Hydroxides

Abstract Propylene oxide polymerization in the presence of layered double hydroxides with different concentration of basic sites on their surface has been studied. It is shown that the polymerization can be catalyzed by both basic and acidic sites. On the basis of kinetic experiments the mechanisms of reaction undergoing were proposed.

Temperature and frequency‐dependent creep and recovery studies on PVDF‐HFP/organo‐modified layered double hydroxides nanocomposites

ABSTRACTA series of poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) loaded with various contents of layered double hydroxides (LDHs) nanoparticles were prepared via a melt mixing method. Detailed investigations on LDH dispersion state in the polymeric matrix conducted by TEM revealed intercalated/exfoliated, and agglomerated structures at low (1 wt %) and high (>3 wt %) loadings of LDH contents, respectively. Wide angle X‐ray scattering and DSC results showed that incorporation of LDH into PVDF‐HFP matrix reduced its overall crystallinity and helped to form polar crystallites, while the crystal size at 020 crystallographic directions was found to be most affected by presence and dispersion state of LDH in the matrix. TGA results showed LDH improved thermal stability of matrix however, unlike many other nanomaterials it significantly reduced the residual mass which highlights catalytic role of LDH in degradation of residual carbon char. Detailed analysis on creep and recovery data over wide range of selected temperatures revealed that the creep compliance of nanocomposites are basically controlled by crystallinity and presence of LDH at low and high temperatures, respectively. Based on obtained storage modulus and creep compliance master curves it was also found that the influence of LDH on decreasing the creep compliance and improving viscoelastic properties of PVDF‐HFP over long time period and over high frequency ranges becomes more pronounced. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46352.

Layered double hydroxide nanoparticles: Impact on vascular cells, blood cells and the complement system

The mounting interest in layered double hydroxide (LDH) nanoparticles as drug carriers and bio-imaging contrast agents makes biosafety evaluation of LDH essential. Considering the important role of blood circulation in bio-distribution of nanoparticles, the present work evaluated the impact of MgAl-LDHs on key components of the circulatory system, including vascular cells (vascular smooth muscle cells (SMCs) and endothelial cells (HUVECs)), red blood cells (RBCs), and complement activation. The results showed that LDH had no effects on SMCs and HUVECs at concentrations up to 500 and 10 µg/mL respectively, in terms of cell proliferation and viability. LDH (10 µg/mL) did not change either the migration distance or the number of migrating SMCs in culture. Moreover, LDH (400 µg/mL) had a negligible effect on RBCs’ lysis, and there was no significant increase in levels of complement activation product, C5a, in the presence of LDH (20 or 200 µg/mL). The low toxicity for vascular cells and blood cells combined with low immunogenicity sheds a light on the biosafety of LDH nanoparticles, and encourages further studies into their biomedical applications.

Synthesis of polyacrylamide/layered double hydroxides hybrid composite gel via in situ polymerization and study of its rheological and thermal behavior

A hybrid nanocomposite gel of layered double hydroxides (LDHs)/acrylamide was prepared by polymerization of acrylamide in the presence of LDH via sonochemical shaking method. Acrylamide monomer is initially intercalated in the interlayer of LDH and polymerized within the layers to get the hybrid gel. The morphology and structure properties of the prepared sample were characterized by FT‐IR, XRD, FESEM, particle size, as well as its flow behavior and rheology studies. Thermal analysis was investigated by thermogravimetric analysis method. The thermal analysis was performed at four different heating rates. The successful preparation of the nanocomposite and the intercalation of polyacylamide into the interlayer space of the LDH was confirmed by FT‐IR and XRD analysis. The synthesized gel exhibited a non‐Newtonian flow motion with a pseudo‐plastic behavior. Herschel‐Bulkley model gave a good description on the rheological behavior of the hybrid gel. Four mass loss steps were observed and could be attributed to the removal of weakly absorbed water from the external surface of the hydrotalcite, the removal of interlayer water, the decomposition of interlayer anions and dehydroxylation and the destruction of the layers of LDH, respectively. The apparent activation energy of the decomposition has been calculated by using Kissinger, Flynn‐Wall‐Ozawa (FWO) and modified Coats Redfern methods. The most probable mechanism function describing the nanocomposite degradation was found to be that of Jander equation: . The results are of great interest in the understanding the thermodynamic properties of polyacrylamide/Mg‐Al layered double hydroxide hybrid nanocomposite gel and for its further applications. POLYM. COMPOS., 39:E1606–E1617, 2018. © 2017 Society of Plastics Engineers

Thermal and dynamic mechanical properties of PP/EVA nanocomposites containing organo-modified layered double hydroxides

Abstract In this study, organo-modified layered double hydroxides (LDH) as nanoparticleswere used to prepare hybrid nanocomposites based on polypropylene (PP), ethylene vinyl acetate copolymer (EVA) blend in presence of a maleated polypropylene (PP-g-MA) as compatibilizer via a one-step melt mixing process. Transmission electron microscope (TEM) was employed to determine localization of LDH nanoparticles in the blend nanocomposites. Microstructures of the nanocomposites were studied by means of scanning electron microscopy (SEM). Thermo-mechanical properties of nanocomposites were investigated by dynamic mechanical thermal analysis (DMTA). Differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) were also used to investigate crystallization behavior and degradation process of the nanocomposites, respectively. The results showed that, LDH nanoparticles in the exfoliated and/or intercalated states were mainly localized in the EVA phase. The average particles size of EVA domains was reduced in presence of LDH and PP-g-MA. The storage modulus of nanocomposites was controlled by combination of LDH and PP-g-MA. The crystallization studies revealed that 5wt%LDH and PP-g-MA increased crystallization temperature to 133.4 °C while addition ofLDH in absence of the compatibilizer decreased the crystallization temperature to 122.7 °C.Investigation of thermal degradation behavior of samples indicated that presence of LDH and PP-g-MA in PP/EVA blendsimprovedinitial degradation temperature of nanocomposites by about 43% compared to the neat PP.

Preparation and flame retardancy of polystyrene nanocomposites based on layered double hydroxides

Various layered double hydroxides (LDHs), including MgAl, CoAl, NiAl, and ZnAl-LDHs, were synthesized and modified using sodium dodecyl benzene sulfonate. Nonhalogen flame-retardant PS/LDHs nanocomposites were prepared via melt mixing method. The structure of PS/LDHs nanocomposites was investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) pattern technique, and scanning electronic microscope. Results from XRD indicated that intercalated/exfoliated structure was achieved in the polystyrene matrix. Dynamic mechanical thermal analysis suggested that the storage modulus and Tg for the PS/LDHs nanocomposites was efficiently improved. Thermal and flammability properties of PS nanocomposites were investigated using thermogravimetry and cone calorimetry. Thermal analysis was evaluated and the prepared nanocomposites showed slightly lower thermal stability probably due to the presence of LDH, which starts to decompose at a lower temperature. Compared with neat PS, the peak heat release rate of PS/MgAl and PS/ZnAl-LDHs nanocomposites filled with 5 wt% LDHs is reduced by 7% and 12%, respectively. Among all LDHs, MgAl, and ZnAl-LDHs had a better smoke suppression effect with a reduction of peak smoke production rate and CO release rate of 37% and 44%, respectively. POLYM. COMPOS., 38:1680–1688, 2017. © 2015 Society of Plastics Engineers

Layered double hydroxides as transesterification catalysts and nanofillers for polyester resin

Saturated polyester resins were prepared by reaction of dimethylterephthalate with alkylene glycols in the presence of layered doublehydroxides (hydrotalcites, HT). The effect of HT composition (cation and aniontypes) on the rate and progress of transesterification was investigated. It was found that zinc-aluminum HT intercalated with anionic form of aminolauric acid[HT(ZnAl)ALA] efficiently catalyzes transesterification process, increasing therate of reaction or lowering its temperature when compared to the reaction with use of conventional organic tin catalyst. The polyester resin obtained in this way is transparent, which along with X-ray diffraction data indicates the delamination of clay layers and formation of nanocomposite. The limitation of using ALA-intercalated HT as an additive for polyesters used in coatings is coloration of the resin with an increase of the reaction temperature above 180°C. Colorless polyester was obtained using more thermally stable hydrotalciteintercalated with ethylenediaminetetraacetic acid, however, at the expense of significantly longer reaction time. Using HT(ZnAl)ALA catalyst a two-step synthesis of carboxyl polyester resin was performed and the obtained product was used as a component of powder coating formulation.

Flammability and thermal behavior of polypropylene composites containing dihydrogen phosphate anion‐intercalated layered double hydroxides

Dihydrogen phosphate anion‐intercalated layered double hydroxides (M‐LDHs) was prepared by modification of Mg‐Al‐CO32− layered double hydroxides (LDHs) with anion exchange procedure. The structure of the M‐LDHs was characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscope (TEM). Polypropylene (PP)/LDHs and PP/M‐LDHs composites were prepared by melt compounding. The morphology of PP composites was investigated by TEM and XRD, which demonstrated that M‐LDHs could be well dispersed in PP matrix to form a nano‐scale exfoliated structure. Thermogravimetric analysis showed that thermal stability of PP composites was improved by the presence of LDHs and M‐LDHs. The flammability of PP composites was characterized by limited oxygen index, vertical burning test (UL‐94), FTIR, and cone calorimeter test, and the result showed the fire performance were significantly improved after the addition of LDHs and/or M‐LDHs which can remarkably decrease the heat release rate, total heat release, and the fire performance index. It was proposed that the lamellar structure of LDHs can block the heat, dilute the flammable gases and decrease the temperature, while the replaced H2PO4− into LDHs molecules can enhance the charred layer formation during burning procedure. Inductively coupled plasma mass spectrometer analysis showed that most phosphorus remained in the char layer, suggesting the replaced H2PO4− in LDHs molecules mainly function in the condensed phase. POLYM. COMPOS., 36:2230–2237, 2015. © 2014 Society of Plastics Engineers

In Situ Real Time Infrared Spectroscopy of Sorption of (Poly)molybdate Ions into Layered Double Hydroxides

The sorption of (poly)molybdate ions into layered double hydroxides (LDHs), with Zn(2+) and Al(3+) cations, has been followed by in situ infrared spectroscopy using the attenuated total reflection technique. The exchange between solution molybdate species and interlayer anions has been followed in real time, illustrating the different behavior of molybdate ions and polymolybdate species. In a first part, the Mo(VI) speciation in solution was performed by comparison of thermodynamical calculations and infrared spectroscopy of solutions with different pH. Decomposition of bands between 800 to 1000 cm(-1), corresponding to the (Mo-O) stretching vibration, has permitted to identify major (poly)molybdate species. In the presence of LDH, the measurements have shown a high affinity for heptamolybdate (Mo7O24(6-)) species, and its preferential sorption in comparison with molybdate ions or other protonated polymolybdate species even if it represents very small fractions. From these measurements, the affinity series Mo7O24(6-) > CO3(2-) > MoO4(2-) > SO4(2-) have been directly obtained.

Crystallization of nanocomposites of an isotactic random butene-1/ethylene copolymer and layered double hydroxide

The effect of the presence of a layered double hydroxide (LDH) nanofiller on the crystallization behavior of a random isotactic butene-1/ethylene copolymer was investigated. Addition of LDH enhanced heterogeneous nucleation of the ordering process of the polymer matrix leading to an increase of the temperature of formation of the Form II mesophase on cooling the melt. Consequently, the size of spherulites of the polymer matrix was markedly reduced in the nanocomposites. In contrast, the Form II mesophase–Form I crystal phase transition kinetics and the final crystallinity were not affected by the presence of LDH. Addition of the LDH nanofiller led to a beneficial increase of the stiffness which suggests a route for compensating of the lower stiffness of the random copolymer compared to the homopolymer. Random copolymerization accelerates the disadvantageous room-temperature mesophase–crystal transition, but results in a reduction of the crystallinity. The addition of LDH counterbalances the lowering of the crystal fraction.

Isothermal crystallization and mechanical properties of poly(butylene succinate)/layered double hydroxide nanocomposites

Biodegradable poly(butylene succinate) (PBS) and layered double hydroxide (LDH) nanocomposites were prepared via melt blending in a twin-screw extruder. Isothermal crystallization and subsequent melting behavior, thermal stability, crystal structure, spherulitic morphology and mechanical properties of PBS and its nanocomposites were studied by DSC, TGA, WAXD, POM and DMA in detail. The crystallization rate of PBS in its nanocomposites was accelerated by the addition of LDH, due to its heterogeneous nucleation effect. The Avrami equation successfully described the isothermal crystallization kinetics of the nanocomposites. The melting profile of PBS/LDH composites and pure PBS showed the very similar Tc-dependent DSC traces. The TGA analysis revealed that the catalyst effect of Mg and/or Al metals reduced the thermal decomposition temperature of PBS. The spherulite size of PBS/LDH nanocomposites decreased and the spherulite density increased remarkably with an increase of LDH, however, the crystalline structure was not influenced by the presence of LDH, as evidenced by the same diffraction peaks from WAXD patterns. The DMA results indicated that a significant enhancement of the modulus of the nanocomposites was achieved.

Isothermal crystallization and melting behavior of polypropylene/layered double hydroxide nanocomposites

The effect of layered double hydroxide (LDH) nanolayers on the crystallization behavior of polypropylene (PP) was studied based on the preparation of nanocomposites by a melt intercalation method. The isothermal crystallization kinetics and subsequent melting behavior of PP/LDH hybrids were studied with differential scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). Studies revealed that the LDH promoted heterogeneous nucleation, accelerating the crystallization of PP. The Avrami equation successfully describes the isothermal crystallization kinetics of PP/LDH hybrids and signifies heterogeneous nucleation in crystal growth of PP. The varying values of Avrami exponent ( n) and half crystallization time ( t 1/2) of PP and PP/LDH hybrids describes overall crystallization behavior. The crystallite size ( D h k l ) and distribution of different crystallites in PP varied in presence of LDH. A significant increase in melting temperature is observed for PP/LDH hybrids. The POM showed that smaller and less perfect crystals were formed in nanocomposites because of molecular interaction between PP chains and LDH. The value of fold surface free energy ( σ e) of PP chains decreased with increasing LDH content. Finally, the overall results signify that LDH at nanometer level acted as nucleating agent and accelerate the overall crystallization process of PP.

Non-isothermal crystallization kinetics and activity of filler in polypropylene/Mg–Al layered double hydroxide nanocomposites

The non-isothermal crystallization behaviour of Mg–Al layered double hydroxide (LDH)/polypropylene (PP) nanocomposites prepared by melt-dispersion was investigated through differential scanning calorimetry and discussed in comparison with that of montmorillonite (MMT)/PP ones. Combined effects of the LDH interlamellar modification and blending the PP with maleic anhydride-grafted PP (PP-g-MAH) and maleic anhydride-grafted poly(styrene-co-ethylenebutylene-co-styrene) (SEBS-g-MAH) were analysed. Different approaches were applied to determinate the crystallization kinetic parameters. The nucleation activity parameter indicated that LDH particle resulted active for heterogeneous nucleation of PP. Overall; the crystallization rate constant of the PP increased in presence of LDH in a similar extension that in presence of MMT nanoparticles. By applying an isoconversional method to the calorimetric data it was found that the effective activation energy decreased because of the effect of the nanoparticles and its value displayed different growing trends with the crystallization degree depending of the nanocomposite composition.

Synthesis and characterization of ethylene vinyl acetate/Mg–Al layered double hydroxide nanocomposites

AbstractMg–Al layered double hydroxide (LDH)/Ethylene vinyl acetate (EVA‐28) nanocomposites were prepared through solution intercalation method using organically modified layered double hydroxide (DS‐LDH). DS‐LDH was made by the intercalation of sodium dodecyl sulfate (SDS) ion. The structure of DS‐LDH and its nanocomposites with EVA‐28 was determined by X‐ray diffraction (XRD) and transmission electron microscope (TEM) analysis. XRD analysis shows that the original peak of DS‐LDH shifted to lower 2θ range and supports the formation of intercalated nanocomposites while, TEM micrograph shows the presence of partially exfoliated LDH nanolayers in addition to orderly stacked LDH crystallites in the polymer matrix. The presence of LDH in the nanocomposites has been confirmed by Fourier transform infrared (FTIR) analysis. The mechanical properties show significant improvement for the nanocomposite with respect to neat EVA‐28. Thermogravimetric (TGA) analysis shows that thermal stability of the nanocomposites is higher than that of EVA‐28. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1845–1851, 2007