Influence of maleated elastomer on filler dispersion,mechanical and antimicrobial properties of hybrid HDPE/clay/silver nanocomposites

This work analyses the effect of using ethylene-propylene-diene-monomer-grafted maleic anhydride (EPDM-g-MA) as compatibilizer to improve the interfacial properties and toughness of high-density polyethylene–organoclay–silver (HDPE/clay/silver) nanocomposites. EPDM-g-MA was reacted using ultrasound with a solution of AgNO₃ 0.04 M and ethylene glycol using ammonium hydroxide to obtain the silver ammonium complex. This silver-coated maleated EPDM was then melt mixed with HDPE and organoclay (Nanomer I28E) using a twin-screw extruder. Transmission electron microscopy (STEM) and X-ray diffraction (XRD) results confirmed the filler dispersion of both organoclay and silver nanoparticles into HDPE matrix when maleated EPDM was used. Both fillers were better dispersed and exfoliated by using this compatibilizer. The thermal stability enhancement of nanocomposites was confirmed using thermogravimetric analysis. Mechanical and antimicrobial properties demonstrated that better dispersed filler obtained with maleated EPDM enhanced the toughness and antimicrobial behaviour of HDPE/clay/silver hybrid nanocomposites. This confirmed that maleated EPDM was an efficient compatibilizer to obtain hybrid nanocomposites with enhanced properties to be used for several HDPE applications.     

Effect of functionalized polyethylenes on clay dispersion in high density polyethylene nanocomposites

The compatibilization effects provided by maleic anhydride (MA), itaconic acid (IAc), itaconic anhydride (IA), and 2-[2-(dimethylamine)-ethoxy]ethanol (DMAE) functionalized polyethylenes for forming high density polyethylene (HDPE)-based nanocomposites were studied and compared. IAc and IA were grafted into HDPE by melt mixing to obtain functionalized polyethylenes (HDPEgIAc and HDPEgIA) and amino alcohol functionalized polyethylene was prepared by reaction of commercial HDPEgMA with DMAE in the melt to form polyethylene-grafted dimethyl-amine-ethoxy-ethanol (PEgDMAE). Nanocomposites were prepared by melt processing using a twin screw extruder by blending polyethylene and these compatibilizers with a quaternary ammonium surfactant-modified montmorillonite clay (Nanomer I28E). FTIR characterization confirmed the formation of these compatibilizers and confirmed the reaction between HDPEgMA and the amino alcohol. All the compatibilized nanocomposites had better clay exfoliation compared to the uncompatibilized HDPE nanocomposites. Barrier properties, X-ray diffraction and transmission electron microscopy results showed the following order of their performance as a compatibilizer: PEgDMAE > HDPEgAI > HDPEgAcI > HDPEgMA. This behavior was attributed to the specific interactions between the anionic surface of the clay and the functionality of the compatibilizer. Samples with higher clay content showed poorer clay dispersion or intercalation which was attributed to possible clay saturation when the van der Waals attractive interactions between the clay layers become dominant when the distance between them was small enough at a certain concentration of clay. A noticeable reduction in the degree of crystallinity with the incorporation of nanoclay was observed by thermal analysis whereas the melting temperature did not change noticeably.     

Evaluation of different amine‐functionalized polyethylenes as compatibilizers for polyethylene film nanocomposites

The compatibilization effects provided by different amine‐functionalized polyethylenes (PEs) versus those provided by a maleated polyethylene (PEgMA), for forming PE‐based film nanocomposites, were studied. Amine‐functionalized PEs were prepared by reaction of PEgMA with two primary amines, 2‐aminoethanol (EA) and 1,12‐aminododecane (D12), and a tertiary amine, 2‐[2‐(dimethylamino)ethoxy]ethanol (DMAE), in the melt to form the corresponding PEgEA, PEgD12 and PEgDMAE. Nanocomposites were prepared by melt mixing in a twin‐screw extruder PE and these three functionalized compatibilizers with a modified montmorillonite clay. The purpose of the current work was to determine the effect of the various amine‐functionalized PEs on the degree of exfoliation and optical properties of PE–clay nanocomposites in order to obtain nanocomposite films for greenhouse cover applications. Fourier transform infrared analysis confirmed the formation of the amine‐modified PE compatibilizers. Structural, morphological, mechanical, rheological and optical properties of film samples were used to characterize the nanocomposites. All the amine‐modified PE‐compatibilized nanocomposites had better clay exfoliation compared to uncompatibilized PE composites. Results showed that PEgDMAE formed highly exfoliated morphology and a favorable balance between mechanical (stiffness and ductility), optical and thermal insulating film properties even at higher clay contents. It was determined that nanocomposites with greater exfoliated structure showed better optical and thermal insulating film properties. PEgEA and PEgD12 compatibilizers did not provide a better interaction for exfoliation of the organoclay than the PEgMA material. The PEgDMAE compatibilizer led to a highly exfoliated morphology and a favorable balance between mechanical, optical and thermal insulating film properties even at higher clay contents. The PEgDMAE film nanocomposites could be used ideally for greenhouse cover applications. Copyright © 2010 Society of Chemical Industry     

Shear rheology and melt compounding of compatibilized‐polypropylene nanocomposites: Effect of compatibilizer molecular weight

Direct melt compounding was used to prepare nanocomposites of organophilic montmorillonite (o‐mmt) clay dispersed in maleated polypropylenes (PPgMA) as well as nanocomposites of organoclay and polypropylene (PP) modified with various grades of PPgMA compatibilizers. The thermal effect on the rheology and melt compounding was first investigated with a plasticorder. The shear viscosities and the melt flow indices (MFI) of the PPgMA compatibilizers were sensitive to the blending temperature, which had to be varied with the compatibilizer grade to achieve desirable level of torque for extensive exfoliation of organoclay in the plasticorder. However, for low molecular weight oligomer, the clay dispersion was poor because of low shear viscosity and thermal instability. Next, the PPgMA‐modified PP/organoclay nanocomposites were prepared on a corotating twin‐screw extruder. The nanoscale dimensions of the dispersed clay platelets led to significantly increased linear viscoelastic properties, which were qualitatively correlated with the state of exfoliation in the nanocomposites. The relative viscosity (relative to the silicate‐free matrix) curves revealed a systematic trend with the extent of clay exfoliation. Furthermore, the degree of clay dispersion was found to increase with the loading of compatibilizers; however, high loading of compatibilizer compromised the final moduli of the nanocomposites. POLYM. ENG. SCI. 46:289–302, 2006. © 2006 Society of Plastics Engineers     

Evaluations of PP-g-GMA and PP-g-HEMA as a compatibilizer for polypropylene/clay nanocomposites

In this study, we investigated the performances of a hydroxy ethyl methacrylate grafted PP (PP-g-HEMA) and a glycidyl methacrylate grafted PP (PP-g-GMA) as compatibilizers in PP/clay nanocomposites. The compatibilizers were prepared by melt grafting with a radical initiator. Since the PP-g-MA is successfully and widely used in the PP/clay nanocomposites, we also studied three PP-g-MAs containing different amounts of MA and having different molecular weights for a comparison. PP/clay nanocomposites compatibilized by the PP-g-HEMA and the PP-g-GMA show a similar level of the clay interlayer distances with those of the PP-g-MAs. We also investigated the effect of molecular weights of the compatibilizers. In general, the compatibilizer of lower molecular weight was observed to exhibit lower performance as a compatibilizer. It is observed that an increase of polar group content in the modified PP (PP-g-HEMA, PP-g-GMA, and PP-g-MA) always accompanies the molecular weight reduction, which deteriorates the mechanical properties. Thus, we prepared the PP-g-HEMA and PP-g-GMA by incorporation of a styrene comonomer. The compatibilizers (PP-g-HEMA-co-styrene and PP-g-GMA-co-styrene) thus obtained show good performance as a compatibilizer in the PP/clay nanocomposites. We observed that the PP/clay composites containing the PP-g-HEMA-co-styrene and the PP-g-GMA-co-styrene have very well-balanced mechanical properties.     

Preparation and properties of styrene–ethylene–butylene–styrene block copolymer/clay nanocomposites: I. Effect of clay content and compatibilizer types

BACKGROUND: Polymer/clay (silicate) systems exhibit great promise for industrial applications due to their ability to display synergistically advanced properties with relatively small amounts of clay loads. The effects of various compatibilizers on styrene–ethylene–butylene–styrene block copolymer (SEBS)/clay nanocomposites with various amounts of clay using a melt mixing process are investigated. RESULTS: SEBS/clay nanocomposites were prepared via melt mixing. Two types of maleated compatibilizers, styrene–ethylene–butylene–styrene block copolymer grafted maleic anhydride (SEBS‐g‐MA) and polypropylene grafted maleic anhydride (PP‐g‐MA), were incorporated to improve the dispersion of various amounts of commercial organoclay (denoted as 20A). Experimental samples were analyzed using X‐ray diffraction and transmission electron microscopy. Thermal stability was enhanced through the addition of clay with or without compatibilizers. The dynamic mechanical properties and rheological properties indicated enhanced interaction for the compatibilized nanocomposites. In particular, the PP‐g‐MA compatibilized system conferred higher tensile strength or Young's modulus than the SEBS‐g‐MA compatibilized system, although SEBS‐g‐MA seemed to further expand the interlayer spacing of the clay compared with PP‐g‐MA. CONCLUSION: These unusual results suggest that the matrix properties and compatibilizer types are crucial factors in attaining the best mechanical property performance at a specific clay content. Copyright © 2007 Society of Chemical Industry     

High‐density polyethylene nanocomposites using masterbatches of chlorinated polyethylene/graphene oxide

Graphene‐based nanocomposites were generated by solution mixing of the graphene oxide filler with chlorinated polyethylene compatibilizers followed by melt mixing of the solution mixed masterbatches with high‐density polyethylene. Compatibilizers with two different chlorination contents were used in different amounts in order to analyze their effect on the morphology and properties of resulting nanocomposites. Peak melting point as well as overall crystallinity was affected by graphene oxide as well as compatibilizers. Compatibilizer with higher chlorination content also interacted with polar graphene oxide surface more effectively thus leading to better filler dispersion in the composites. The addition of compatibilizers to the composites resulted in their shear and processing stability at higher angular frequencies and temperature, which otherwise was not possible for pure polymer as well as composites without compatibilizer. The mechanical performance of the nanocomposites at ambient conditions was also affected by the factors like filler delamination, plasticization of the matrix, compatibilizer content as well as their chlorination level and amorphous/semicrystalline nature. An increase of 16% in tensile modulus and 21% in strength of the composites with 5 wt% of 25% chlorinated compatibilizer at 0.5 wt% graphene oxide content was observed. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Effect of amphiphilic compatibilizers on the filler dispersion and properties of polyethylene—thermally reduced graphene nanocomposites

Compatibilizers of different chemical structures and specifications were used to enhance the filler exfoliation in nanocomposites of polyethylene and thermally reduced graphene prepared by melt mixing route. The mechanical performance of the compatibilized nanocomposites was observed to be better than PE/G nanocomposites due to enhanced extent of filler exfoliation and distribution. Highest increase of 45% in tensile modulus and 13% in peak stress was observed in the composites. Overall, from the mechanical, rheological, thermal, and calorimetric properties, the compatibilizers with best performance were ethylene acrylic acid (EAA) copolymer and chlorinated polyethylene (CPE25). Furthermore, the extent of filler exfoliation was observed to increase with increasing EAA content thus confirming positive interactions between EAA and thermally reduced graphene, though no specific chemical interactions could be detected. The composite properties were observed to reach maximum around 7.5 wt % EAA content, followed by reduced performance due to extensive matrix plasticization. The observed behaviors were a result of interplay of opposing factors like filler exfoliation due to compatibilizer addition and matrix plasticization due to its lower molecular weight, thus the observed optimum comaptibilizer amount was specific to the compatibilizer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42484.     

Morphology and properties of nylon 6 and high density polyethylene blends in presence of nanoclay and PE‐g‐MA

In this study, we report the synergistic effect of nanoclay and maleic anhydride grafted polyethylene (PE‐g‐MA) on the morphology and properties of (80/20 w/w) nylon 6/high density polyethylene (HDPE) blend. Polymer blend nanocomposites containing nanoclay with and without compatibilizer (PE‐g‐MA) were prepared by melt mixing, and their morphologies and structures were examined with scanning electron microscopy (SEM) and wide angle X‐ray diffractometer (WAXD) study. The size of phase‐separated domains decreased considerably with increasing content of nanoclay and PE‐g‐MA. WAXD study and transmission electron microscopy (TEM) revealed the presence of exfoliated clay platelets in nylon 6 matrix, as well as, at the interface of the (80/20 w/w) nylon 6/HDPE blend–clay nanocomposites. Addition of PE‐g‐MA in the blend–clay nanocomposites enhanced the exfoliation of clays in nylon 6 matrix and especially at the interface. Thus, exfoliated clay platelets in nylon 6 matrix effectively restricted the coalescence of dispersed HDPE domains while PE‐g‐MA improved the adhesion between the phases at the interface. The use of compatibilizer and nanoclay in polymer blends may lead to a high performance material which combines the advantages of compatibilized polymer blends and the merits of polymer nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Crystal and morphology development in immiscible nonpolar polymer blend nanocomposite based on low-density polyethylene and linear low-density polyethylene in presence of clay and compatibilizer

In this work, polyolefin-blend/clay nanocomposites based on low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and organically modified clay (OC) were prepared by melt extrusion. Various grades of maleic anhydride (MA) grafted polyethylene (PE-g-MA) were used and examined as compatibilizers in these nanocomposites. Differential scanning calorimetry analysis showed that OC and compatibilizer affect the crystallization behavior of LDPE/LLDPE with different mechanisms. Thermodynamic calculations of wetting coefficient based on interfacial energy between OC, LD, and LL, Morphological characterization based on field emission scanning electron microscopy, X-ray diffraction, small angles X-ray scattering, and dynamic rheology measurements revealed that the compatibilizer and OC were localized at the interface of LDPE and LLDPE phases with a preferred tendency toward one phase. Results demonstrated that at a specific amount of OC, there is an optimum compatibilizer concentration to achieve nanodispersed OC and beyond that the compatibilizer causes a structural change in the polymer crystalline morphology. It was also found that the tensile property enhancement of LDPE/LLDPE/OC nanocomposites is closely related to the crystalline structure development made by incorporation of both OC and compatibilizer.     

Experimental and computational investigation of EVOH/clay nanocomposites

Ethylene–vinyl alcohol copolymer (EVOH)/organoclay nanocomposites were prepared via a dynamic melt‐intercalation process. The effect of compatibilizers on the melt blending torque, intercalation level, and morphology of EVOH/organoclay systems was investigated. Maleic anhydride grafted ethylene vinyl acetate (EVA‐g‐ MA), or maleic anhydride grafted linear low‐density polyethylene (LLDPE‐g‐MA), were used to compatibilize EVOH with clay, at various concentrations (1, 5, and 10 wt %). Computer‐simulation techniques are used to predict structural properties and interactions of EVOH with compatibilizers in the presence and absence of clay. The simulation results strongly support the experimental findings and their interpretation. X‐ray diffraction shows enhanced intercalation within the galleries when the compatibilizers were added. Interestingly, results were obtained for the EVOH/clay/compatibilizer systems, owing to a high level of interaction developed in these systems. Thermal analysis shows that, upon increasing the compatibilizer content, lower crystallinity levels result, until at a certain compatibilizer content no crystallization is taking place. Significantly higher mixing viscosity levels were obtained for the EVOH/organoclay blends compared with the neat EVOH polymer. The storage modulus was higher compared with the uncompatibilized EVOH/organoclay blend in the presence of EVA‐g‐MA compatibilizer (at all concentrations), and only at low contents of LLDPE‐g‐MA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2060–2066, 2005     

Polypropylene/Clay nanocomposites: Effect of compatibilizer on the thermal,crystallization and dynamic mechanical behavior

Polypropylene (PP)/clay nanocomposites are prepared using different grades of PP, compatibilizers, and organically modified clays. The melt intercalation of the PP is carried out in presence of a compatibilizer. The nanocomposites are characterized using various techniques for the structure and properties. X‐ray diffraction results indicate well‐defined structures. Thermogravimetric analysis indicates improved thermal stability of PP/clay nanocomposites. Isothermal crystallization studies carried out using differential scanning calorimeter illustrate enhanced crystallization of PP in all the nanocomposites. Optical microscopic study demonstrates that the nanocomposites can be crystallized at higher temperatures, exhibiting well‐defined birefringent structures. The dynamic mechanical analysis reveals higher storage moduli over a temperature range of ?40⁰C to 120⁰C for nanocomposites, and the extent of increase in the storage modulus is dependent on the type of compatibilizer used.     

Radiation synthesis, characterisation and antimicrobial application of novel copolymeric silver/poly(2-hydroxyethyl methacrylate/itaconic acid) nanocomposite hydrogels

Silver nanoparticles were fabricated via in situ reduction of silver nitrate embedded in swollen P(HEMA/IA) hydrogel, using gamma radiolysis method. Copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA), previously synthesised by gamma radiation for wound dressing application, were used as a carrier and a stabilising agent, while ethyl alcohol was used as a free radical scavenger. The influence of different P(HEMA/IA) hydrogels and silver salt concentrations on the size and distribution of nanoparticles was investigated. The Ag/P(HEMA/IA) nanocomposites were characterised by high resolution scanning electron microscopy, energy dispersive spectroscopy, wide-angle X-ray diffraction, UV-Vis spectroscopy and swelling measurements. Escherichia coli (Gram-negative bacterium), Staphylococcus aureus (Gram-positive bacterium) and Candida albicans (fungus) were used to prove the antimicrobial properties of Ag/P(HEMA/IA) nanocomposites. The inhibition kinetics of bacteria growth was investigated by measuring the colony-forming unit. The antimicrobial effectiveness of the Ag/P(HEMA/IA) hydrogel nanocomposite was demonstrated even at small silver concentrations. P(HEMA/IA) hydrogels containing nanosilver particles was found suitable to be used as wound dressing.     

Influence of two compatibilizers on clay/PP nanocomposites properties

This article investigates the influence on mechanical properties of using a two compatibilizer system. Cloisite‐Na Clay (ClNa) was organically modified in different ways with a polyethermonoamine and maleated polypropylene (MA‐g‐PP) added as a second compatibilizer. A corotating twin‐screw extruder was used to obtain nanocomposites based on polypropylene via the melt intercalation technique. X‐ray diffraction and differential scanning calorimetric results showed that intercalated nanocomposites with improved thermal stability were obtained. Increases of 8% in tensile strength, 34% in modulus, and 20% in crystallinity were observed. Also an increase of 23% in creep properties was observed when using these two compatibilizer system and 1% clay. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Evaluation of polypropylene grafted with maleic anhydride and styrene as a compatibilizer for polypropylene/clay nanocomposites

Among modified Poly(propylene)s (PPs) grafted with polar monomers, PP grafted with maleic anhydride (PP-g-MAH) is known to be the most efficient compatibilizer for PP/clay nanocomposites, since it provides well-dispersed nanostructures and yields optimal physical properties of the nanocomposites. One drawback of this material, however, is that it becomes brittle and its viscosity decreases drastically, leading to nanocomposites with low toughness as the graft degree of MAH increases. Therefore, there is a limitation to increasing both stiffness and toughness of PP/clay nanocomposites with PP-g-MAH. In this study, we investigated the performance of a PP grafted with maleic anhydride and styrene (PP-g-MAH-St) as compatibilizers in PP/clay nanocomposites. It was found that the incorporation of styrene as a comonomer prevents molecular weight reduction of the PP main chain upon high loading of a radical initiator for high graft degree of MAH. The compatibilizers (PP-g-MAH-St) thus obtained show good compatibilizing performance in PP/clay nanocomposites. The PP/clay nanocomposites compatibilized by PP-g-MAH-St show both high stiffness and toughness, which is accomplished by using a compatibilizer of higher viscosity compared with PP-g-MAH.     

Interfacially compatibilized LDPE/POE blends reinforced with nanoclay: investigation of morphology,rheology and dynamic mechanical properties

Morphological, melt rheological and dynamic mechanical properties of low-density polyethylene (LDPE)/ethylene–octene copolymer (POE)/organo-montmorillonite (OMMT) nanocomposites, prepared via melt compounding were studied. The XRD traces indicated different levels of intercalated structures for the nanocomposites. Addition of a compatibilizer (PE-g-MA) improved the intercalation process. TEM results revealed existence of clay layers in both phases but they were mainly localized in the elastomeric POE phase. Addition of 5 wt% OMMT to the LDPE/POE blend led to reduction in the size of the elastomer particles confirmed by AFM. The complex viscosity and storage modulus showed little effect of the presence of the clay when no compatibilizer was added. As the extent of exfoliation increased with addition of compatibilizer, the linear viscoelastic behavior of the composites gradually changed specially at low-frequency regions. The interfacially compatibilized nanocomposites with 5 wt% OMMT had the highest melt viscosity and modulus among all the studied nanocomposites and blends. Also, this particular composition showed the best improvement in dynamic storage modulus. The results indicated that clay dispersion and interfacial adhesion, and consequently different properties of LDPE/POE/clay nanocomposites, are greatly affected by addition of compatibilizer.     

Experimental and MD simulation study on the physical and mechanical properties of organically modified montmorillonite clay and compatibilized linear low density polyethylene nanocomposites

Understanding the interfacial interactions plays a key role in controlling mechanical and physical properties of polymer/clay nanocomposites (PCNs). In this work, the surface interactions between constituents of experimentally prepared PCNs which are the pristine linear low density polyethylene (PE) chains, PE compatibilizers, montmorillonite clay surface layer, and surfactants were studied quantitatively by employing molecular dynamics simulation technique. The interaction energy between the polymer and the clay was found to be inversely proportional with the volume of the surfactant which decreases the electrostatic interactions between the compatibilizer and the hydrophilic clay surface. However, the van der Waals (vdW) interactions between alkyl tails of surfactants and the PE chains increase with the tail length of the surfactants. The most attractive interaction was between the surfactant's head group and the clay surface. We showed that there existed fine balance between the electrostatic and vdW type forces on the stability and the enhanced properties of the PE–organoclay nanocomposites. Calculated interaction energies were then correlated to the experimentally measured mechanical properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45817.     

Effect of PEgMA/amine silane compatibilizer on clay dispersion of polyethylene-clay nanocomposites

The compatibilization effects provided by an amine silane modified polyethylene (PEgAS) versus those by a maleated polyethylene (PEgMA), for forming PE–clay based nanocomposites, were studied. PEgAS was prepared by condensation reaction between PEgMA and g-(aminopropyl) triethoxy silane (APTS). It had the triethoxy-silane functionality on one end and was solution mixed with an organomodified clay (Cloisite 20A) to promote the reaction of the silane groups with the hydroxyl groups on the surface of the clay. The obtained masterbatches were then compounded with PE to obtain PE–clay nanocomposites by melt blending in a twin screw extruder, using different compatibilizers and clay contents. FTIR, XRD, STEM, and Instron were used to characterize the structural, morphological, and mechanical properties of the nanocomposites. Results showed that the PEgAS formed more exfoliated–intercalated morphology and better mechanical properties, especially in modulus and tensile strength as compared with PEgMA composites and neat PE. The Young modulus was 35% higher, and the tensile strength was 18% higher with PEgAS composites.     

Effect of Ionomeric Compatibilizer on Clay Dispersion in Polyethylene/Clay Nanocomposites

Summary: Linear low‐density polyethylene (LLDPE)/clay nanocomposites are obtained and studied by using a zinc‐neutralized carboxylate ionomer as a compatibilizer. LLDPE‐g‐MA is used as a reference compatibilizer. Two different clays, natural montmorillonite (Closite Na⁺) and a chemically modified clay Closite 20A have been used. Nanocomposites are prepared by melt blending in a twin‐screw extruder using two mixing methods: two‐step mixing and one‐step mixing. The relative influence of each compatibilizer is determined by wide‐angle X‐ray diffraction structural analysis and mechanical properties. The results are analyzed in terms of the effect of the compatibilizing agent and incorporation method in the clay dispersion, and the mechanical properties of the nanocomposites. Experimental results confirm that the film samples with ionomer show a good mechanical performance only slightly below that of the samples with maleic anhydride (MA). The two‐step mixing conditions result in better dispersion and intercalation for the nanofillers than one‐step mixing. The exfoliation of clay platelets leads to an improved thermal stability of the composite. The oxygen permeability of the clay nanocomposites, using ionomer as a compatibilizer, is decreased by the addition of the clay.

TEM image of a PE/4 wt.‐% Closite 20A nanocomposite formed using ionomer.     

Preparation of dynamically vulcanized thermoplastic elastomer nanocomposites based on LLDPE/reclaimed rubber

Dynamically vulcanized thermoplastic elastomers nanocomposites (TPV nanocomposites) based on linear low density polyethylene (LLDPE)/reclaimed rubber/organoclay were prepared via one‐step melt blending process. Maleic anhydride grafted polyethylene (PE‐g‐MA) was used as a compatibilizing agent. The effects of reclaimed rubber content (10, 30, and 50 wt %), nanoclay content (3, 5, and 7 wt %), and PE‐g‐MA on the microstructure, thermal behavior, mechanical properties, and rheological behavior of the nanocomposites were studied. The TPV nanocomposites were characterized by X‐ray diffraction, transmission electron microscopy, scanning electron microscopy (SEM), differential scanning calorimeter, mechanical properties, and rheometry in small amplitude oscillatory shear. SEM photomicrographs of the etched samples showed that the elastomer particles were dispersed homogeneously throughout the polyethylene matrix and the size of rubber particles was reduced with introduction of the organoclay particles and compatibilizer. The effects of different nanoclay contents, different rubber contents, and compatibilizer on mechanical properties were investigated. Increasing the amount of nanoclay content and adding the compatibilizer result in an improvement of the tensile modulus of the TPV nanocomposite samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011