Ethylene propylene diene terpolymer/ethylene vinyl acetate/layered silicate ternary nanocomposite by solution method

A new ternary nanocomposite has been developed using ethylene propylene diene terpolymer (EPDM), ethylene vinyl acetate (EVA‐45) copolymer, and organically modified layered silicate (16 Me‐MMT) from sodium montmorillonite (Na⁺‐MMT). Wide angle X‐ray diffraction and transmission electron microscopic analysis confirmed the intercalation of the polymer chains in between the organosilicate layers and the nanoscale distribution of 16 Me‐MMT in polymer matrix, respectively. The measurement of mechanical properties for 2–8 wt% of 16 Me‐MMT loadings showed a significant increase in tensile strength, elongation at break, and modulus at different elongations. Such an improvement in mechanical properties has been correlated based on the fracture behavior of nanocomposite by SEM analysis. Thermal stability of EPDM/EVA/layered silicate ternary nanocomposites also showed substantial improvements compared with the neat EPDM/EVA blend, confirming thereby the formation of a high performance nanocomposite. POLYM. ENG. SCI., 46:437–843, 2006. © 2006 Society of Plastics Engineers     

Ethylene vinyl acetate/ethylene propylene diene terpolymer‐blend‐layered double hydroxide nanocomposites

Ethylene vinyl acetate (EVA‐45)/ethylene propylene diene terpolymer (EPDM) blend‐layered double hydroxide (LDH) nanocomposites have been prepared by solution blending of 1:1 weight ratio of EVA and EPDM with varying amounts of organo LDH (DS‐LDH). X‐ray diffraction and transmission electron microscopy analysis suggest the formation of partially exfoliated EVA/EPDM/DS‐LDH nanocomposites. Measurement of mechanical properties of the nanocomposites (3 wt% DS‐LDH content) show that the improvement in tensile strength and elongation at break are 35 and 12% higher than neat EVA/EPDM blends. Dynamic mechanical thermal analysis also shows that the storage modulus of the nanocomposites at glass transition temperature is higher compared to the pure blend. Such improvements in mechanical properties have been correlated in terms of fracture behavior of the nanocomposites using scanning electron microscopy analysis. Thermal stability of the prepared nanocomposites is substantially higher compared to neat EVA/EPDM blend, confirming the formation of high‐performance polymer nanocomposites. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

EPDM/silicone blend layered silicate nanocomposite by solution intercalation method: Morphology and properties

Ethylene–propylene–diene terpolymer (EPDM)/silicone blend nanocomposites are prepared by solution method for the first time. EPDM and silicone rubber in their 50:50 (by weight) blend is intercalated within the silicate sheets of organically modified montmorillonite. Organic modification to the pristine sodium montmorillonite (Na‐MMT) surfaces is carried out by ion‐exchange reaction using hexadecyl ammonium chloride. The incorporation of such organic functional group makes Na‐MMT hydrophobic and expands the interlayer spacing between silicate sheets. The intercalated structure of EPDM/silicone blend nanocomposites is characterized by the X‐ray diffraction. Transmission electron microscopic characterization visualized the presence of both exfoliated and intercalated layered silicate in the polymer nanocomposites. The mechanical properties of the nanocomposites show a maximum improvement in tensile strength and elongation at break of 23 and 68%, respectively, compared with EPDM/silicone blend. The dielectric measurement demonstrates the increase in relative permittivity for the nanocomposite than the pure blend. The increase in the onset temperature of the thermal degradation of nanocomposites (∼52°C) corresponding to 1 wt% decomposition indicates the enhancement of thermal stability of (EPDM)/silicone blend due to interaction with silicates. POLYM. COMPOS., 35:1834–1841, 2014. © 2014 Society of Plastics Engineers     

Natural rubber/poly(ethylene‐co‐vinyl acetate)‐blend‐based nanocomposites

Natural rubber (NR)/poly(ethylene‐co‐vinyl acetate) (EVA) blend–clay nanocomposites were prepared and characterized. The blend nanocomposites were prepared through the melt mixing of NR/EVA in a ratio of 40/60 with various amounts of organoclay with an internal mixer followed by compression molding. X‐ray diffraction patterns revealed that the nanocomposites formed were intercalated. The formation of the intercalated nanocomposites was also indicated by transmission electron microscopy. Scanning electron microscopy, used to study the fractured surface morphology, showed that the distribution of the organoclay in the polymer matrix was homogeneous. The tensile modulus of the nanocomposites increased with an increase in the organoclay content. However, an increase in the organoclay content up to 5 phr did not affect the tensile strength, but the organoclay reduced this property when it was increased further. This study also indicated that a low silicate content dispersed in the blend matrix was capable of increasing the storage modulus of the material. The addition of the organoclay also increased the decomposition temperature of the NR/EVA blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 353–362, 2006     

Ethylene vinyl acetate/Mg‐Al LDH nanocomposites by solution blending

Partially exfoliated ethylene vinyl acetate (EVA‐40, 40% vinyl acetate content)/layered double hydroxide (LDH) nanocomposites using organically modified layered double hydroxide (DS‐LDH) have been synthesized by solution intercalation method. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) studies of nanocomposites shows the formation of exfoliated LDH nanolayers in EVA‐40 matrix at lower DS‐LDH contents and partially intercalated/exfoliated EVA‐40/MgAl LDH nanocomposites at higher DS‐LDH contents. These EVA‐40/MgAl LDH nanocomposites demonstrate a significant improvement in tensile strength and elongation at break for 3 wt% of DS‐LDH filler loading compare to neat EVA‐40 matrix. Thermogravimetric analysis also shows that the thermal stability of the nanocomposites increases with DS‐LDH content in EVA‐40. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Effect of vinyl acetate content on the mechanical and thermal properties of ethylene vinyl acetate/MgAl layered double hydroxide nanocomposites

Ethylene vinyl acetate (EVA)/Mg‐Al layered double hydroxide (LDH) nanocomposites using EVA of different vinyl acetate contents (EVA‐18 and EVA‐45) have been prepared by solution blending method. X‐ray diffraction and transmission electron microscopic studies of nanocomposites clearly indicate the formation of exfoliated/intercalated structure for EVA‐18 and completely delaminated structure for EVA‐45. Though EVA‐18 nanocomposites do not show significant improvement in mechanical properties, EVA‐45 nanocomposites with 5 wt % DS‐LDH content results in tensile strength and elongation at break to be 25% and 7.5% higher compared to neat EVA‐45. The data from thermogravimetric analysis show that the nanocomposites of EVA‐18 and EVA‐45 have ≈10°C higher thermal decomposition temperature compared to neat EVA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Vinyl acetate content and electron beam irradiation directed alteration of structure,morphology, and associated properties of EVA/EPDM blends

A series of ethylene vinyl acetate/ethylene–propylene diene elastomer (EVA/EPDM) blends with four types of EVAs with various vinyl acetate (VA) content, are prepared without and with crosslinker, trimethylol propane triacrylate (TMPTA). These are irradiated by electron beam (EB). As the VA content increases, the gel content, i.e., degree of crosslinking of EVA/EPDM blends, is increased. With increase in VA content, the modulus and tensile strength are decreased but elongation at break is increased due to increase in amorphousness. On EB irradiation, modulus and tensile strengths are increased but at the cost of elongation at break. Crystallinities of all blends are decreased with increase in VA and EB crosslinking. The thermal stability of EVA/EPDM blend is decreased with increase in VA content but increased after EB irradiation. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) show that with increase in VA content the miscibility of two polymers keeps on increasing, which even become more after EB irradiation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43468.     

Synthesis of silane‐grafted ethylene vinyl acetate copolymer and its application to compatibilize the blend of ethylene‐propylene‐diene copolymer and silicone rubber

Vinyltrimethoxysilane‐grafted ethylene vinyl acetate copolymer (EVA‐g‐VTMS) was synthesized and applied to compatibilize ethylene‐propylene‐diene copolymer (EPDM)/methyl vinyl silicone rubber (MVQ) blends. The silane‐grafting was successfully proved by differential scanning calorimetry, FTIR spectroscopy and XPS spectroscopy. The additive amount of the compatibilizer (EVA‐g‐VTMS) was optimized to be 10 phr (parts per hundred of rubber in weight) based on analysis of scanning electron microscopy, mechanical properties, aging properties, dynamic mechanical properties, rheological properties and thermal properties. Compared with the blend without EVA‐g‐VTMS, results show that the blend with 10 phr of EVA‐g‐VTMS exhibits the finest morphology. Tensile strength, elongation at break, modulus at 100% elongation, tear strength and TE index increase by 82.5%, 16.9%, 60.0%, 40.9%, and 41.9%, respectively. Dynamic mechanical analysis reveals storage modulus increase and glass transition temperatures of EPDM and MVQ move closer to each other. Rheological analysis shows a decrease in complex modulus and complex viscosity, and the processibility of the blend was improved. Furthermore, thermogravimetric analysis shows enhancement of thermal stability. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers     

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     

Gamma radiation aging of EVA/EPDM blends: Effect of vinyl acetate (VA) content and radiation dose on the alteration in mechanical,thermal, and morphological behavior

A series of ethylene vinyl acetate (EVA)/ethylene‐propylene diene elastomer (EPDM) blends (50/50 ratio) with four types of EVAs were prepared using brabender type batch mixer followed by compression molding. All compression‐molded samples were exposed to gamma radiation at 500, 1000, and 1500 kGy doses and were subjected to mechanical, compression set, thermal and morphological test. The % retention in tensile strength, elongation, and hardness were found higher for higher vinyl acetate (VA) containing radiation aged EVA/EPDM blends. The compression set value was decreased with increase of VA content. The thermal degradation kinetics of high VA containing irradiated blend (EVA40/EPDM) (EVA40 is 40%VA containing EVA) was found slower than those of lower VA containing blend (EVA18/EPDM). The surface morphology for EVA18/EPDM sample was transformed into more irregular one with more cracks and fragmented segments by aging at 1500 kGy dose while surface for EVA40/EPDM sample was found comparatively smooth, fine, and continuous with very few cracks and fragmented parts at similar dose. Thus, from the measured properties and morphology, it was revealed that the degree of degradation of blends kept on decreasing with increase in VA content. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46216.     

Preparation and properties of new EPDM/vermiculite nanocomposites

Novel nanocomposites based on ethylene‐propylene‐diene rubber (EPDM) and maleic anhydride‐modified vermiculite (VMT) were prepared. Maleic anhydride (MA) acts both as the intercalation agent for VMT and as a vulcanizing agent for EPDM matrix. It also acts as a compatibilizer for EPDM and VMT phases. From analysis by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), the silicate layers of the VMT were exfoliated and dispersed uniformly in the EPDM matrix as monolayers. The thermal properties of the nanocomposites were investigated by dynamic mechanical thermal analysis and thermogravimetric analysis; a strong rubber‐filler interaction in the nanocomposites was manifested in the measured temperature range by the result of storage modulus. At the same time, there was some enhancement in degradation behavior between the nanocomposites and EPDM matrix. The nanocomposites exhibited a great improvement in tensile strength and modulus, as well as elongation at break. Finally, the effects of MA addition on the formation of nanometric reinforcement and on the mechanical properties of nanocomposites are discussed. POLYM. COMPOS., 26:706–712, 2005. © 2005 Society of Plastics Engineers     

Preparation and properties of nano‐CaCO3/acrylonitrile‐butadiene‐styrene composites

CaCO₃/acrylonitrile‐butadiene‐styrene (ABS) and CaCO₃/ethylene‐vinyl acetate copolymer (EVA)/ABS nanocomposites were prepared by melting‐blend with a single‐screw extruder. Mechanical properties of the nanocomposites and the dispersion state of CaCO₃ particles in ABS matrix were investigated. The results showed that in CaCO₃/EVA/ABS nanocomposites, CaCO₃ nanoparticles could increase flexural modulus of the composites and maintain or increase their impact strength for a certain nano‐CaCO₃ loading range. The tensile strength of the nanocomposites, however, was appreciably decreased by adding CaCO₃ nanoparticles. The microstructure of neat ABS, CaCO₃/ABS nanocomposites, and CaCO₃/EVA/ABS nanocomposites was observed by scanning electron microscopy. It can be found that CaCO₃ nanoparticles were well‐dispersed in ABS matrix at nanoscale. The morphology of the fracture surfaces of the nanocomposites revealed that when CaCO₃/EVA/ABS nanocomposites were exposed to external force, nano‐CaCO₃ particles initiated and terminated crazing (silver streak), which can absorb more impact energy than neat ABS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and characterization of polymer/organosilicate nanocomposites based on unmodified LDPE

Low‐density polyethylene (LDPE)/silicate nanocomposites were prepared by the melt compounding and solution blend methods using unmodified LDPE polymer and layered silicates with different aspect ratio. X‐ray diffraction (XRD) analysis performed on composites obtained by dispersing the organosilicates in molten LDPE evidenced an exfoliated or partially exfoliated structure for the low aspect ratio silicate (laponite) in contrast to the high aspect ratio silicate (montmorillonite), which led to the formation of intercalated nanocomposites. With regard to the preparation method, the melt compounding method was more effective in forming exfoliated/highly intercalated LDPE nanocomposites compared with the solution blend method (using CCl₄ as a solvent). A gradual increase in crystallization temperatures (T_c) with increasing laponite content for LDPE‐organolaponite nanocomposites was revealed by differential scanning calorimetry (DSC) measurements. Thermogravimetric analysis and tensile measurements results indicated that thermal stability and elastic modulus increment were more prevalent for nanocomposites prepared using organomontmorillonite as filler. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Properties and morphologies of elastomer blends modified with EPDM‐g‐poly[2‐dimethylamino ethylmethacrylate]

The graft copolymerization of 2‐dimethylamino ethylmethacrylate (DMAEMA) onto ethylene propylene diene mononer rubber (EPDM) was carried out in toluene via solution polymerization technique at 70°C, using dibenzoyl peroxide as initiator. The synthesized EPDM rubber grafted with poly[DMAEMA] (EPDM‐g‐PDMAEMA) was characterized with ¹H‐NMR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The EPDM‐g‐PDMAEMA was incorporated into EPDM/butadiene acrylonitrile rubber (EPDM/NBR) blend with different blend ratios, where the homogeneity of such blends was examined with scanning electron microscopy and DSC. The scanning electron micrographs illustrate improvement of the morphology of EPDM/NBR rubber blends as a result of incorporation of EPDM‐g‐PDMAEMA onto that blend. The DSC trace exhibits one glass transition temperature (T_g) for EPDM/NBR blend containing EPDM‐g‐PDMAEMA, indicating improvement of homogeneity. The physico‐mechanical properties after and before accelerated thermal aging of the homogeneous, and inhomogeneous EPDM/NBR vulcanizates with different blend ratios were investigated. The physico‐mechanical properties of all blend vulcanizates were improved after and before accelerated thermal aging, in presence of EPDM‐g‐PDMAEMA. Of all blend ratios under investigation EPDM/NBR (75/25) blend possesses the best physico‐mechanical properties together with the best (least) swelling (%) in brake fluid. Swelling behavior of the rubber blend vulcanizates in motor oil and toluene was also investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Nanostructure of EVA/organoclay nanocomposites: Effects of kinds of organoclays and grafting of maleic anhydride onto EVA

Nanostructure of poly(ethylene‐co‐vinyl acetate)/organically modified montmorillonite (MMT; EVA/organoclay) nanocomposites prepared by melt intercalation process was investigated using X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Three kinds of organoclays were used to see their influences on the nanostructure of the EVA hybrids. The effects of the polar interactions between the polymer and the silicate layers of organoclays were also investigated by grafting maleic anhydride onto EVA. It was found that the strong polar interactions between the polymer and the silicate layers of organoclays are critical to the formation of polymer‐layered silicate nanocomposites. The results also showed that increasing the mixing temperature was unfavorable to improve the dispersion of organoclays in the EVA matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1901–1909, 2003     

The influence of matrix viscosity and composition on the morphology,rheology, and mechanical properties of thermoplastic elastomer nanocomposites based on EPDM/PP

The morphological and rheological properties of thermoplastic elastomer nanocomposites (TPE nanocomposites) were studied using different viscosities of polypropylene (PP) and ethylene‐propylene‐diene monomer (EPDM) rubber content (20, 40, 60 wt%). The components, namely EPDM, PP, Cloisite 15A, and maleic anhydride‐modified PP as compatibilizer, were compounded by a one‐step melt mixing process in a laboratory internal mixer. The structure of the nanocomposites was characterized with X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and rheometry in small amplitude oscillatory shear. The distribution state of the clay between the two phases (PP and EPDM) was found to be dependent on the viscosity ratio of PP to EPDM. In the nanocomposites prepared based on low viscosity PP (LVP) and EPDM, the clay was mostly dispersed into the PP phase and the size of the dispersed rubber particles decreased in comparison with unfilled but otherwise similar blends. However, the dispersed elastomer droplet size in the high viscosity PP (HVP) blends containing 40 and 60% EPDM increased with the introduction of the clay. For TPE nanocomposites, the dependence of the storage modulus (G′) on angular frequency (ω) followed a clear nonterminal behavior. The increase in the storage modulus and the decrease in the terminal zone slope of the elastic modulus curve were found to be larger in the LVP nanocomposite in comparison with the HVP sample. The yield stress of nanoclay‐filled blends prepared with LVP increased more than that of HVP samples. The tensile modulus improved for all nanocomposites but a higher percentage of increase was observed in the case of LVP samples. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Flame retardant properties of EVA‐nanocomposites and improvements by combination of nanofillers with aluminium trihydrate

Flame retardant nanocomposites are synthesized by melt‐blending ethylene–vinyl acetate copolymers (EVA) with modified layered silicates (montmorillonites). Thermogravimetric analysis performed under different atmospheres (nitrogen and air) demonstrated a clear increase in the thermal stability of the layered silicate‐based nanocomposites. The use of the cone calorimeter to investigate the fire properties of the materials indicated that the nanocomposites caused a large decrease in heat release. The char‐formation is the main factor important for improvement and its function is outlined. Further improvements of the flame retardancy by combinations of nanofillers and traditional FR‐additives on the basis of metal hydroxides were also studied. Copyright © 2002 John Wiley & Sons, Ltd.     

Preparation and properties of novel natural rubber/organo‐vermiculite nanocomposites

Polymer‐layered silicate nanocomposites have an attracting increasing attention over recent years because of their unique mechanical, thermal, and other properties. In this article, a new kind of natural rubber (NR)/organo‐vermiculite (OVMT) nanocomposites were investigated. The vermiculite (VMT) was intercalated by cetyltrimethylammonium bromide with ball mill method. The intercalation led to an increase of the d₍₀₀₁₎ of VMT from 1.46 nm to 4.51 nm. NR/OVMT nanocomposites were prepared via a melt process in a HAAKE mixer and were analyzed by X‐ray diffraction and scanning electron microscope observations. The mechanical properties of the vulcanized nanocomposites were tested. It was found that the tensile strength and the elongation at the breaking point of the NR/OVMT nanocomposites loading 15 phr of the OVMT reached 28.4 MPa and 623.2%, respectively. The 300% modulus, tear strength, and hardness (Shore A) of the nanocomposites increased with the increase of the OVMT loading. The thermal properties of the nanocomposites were investigated by dynamic mechanical analysis, and the results showed that the storage modulus and the glass transition temperature of the nanocomposites were increased. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Experimental investigation of the linear viscoelastic response of EVA‐based nanocomposites

Linear viscoelastic behaviors of ethylene‐vinyl acetate (EVA)‐layered silicate nanocomposites were investigated. EVA with vinyl acetate (VA) content of 18 and 28% by weight and commercially modified montmorillonite clay (Cloisite® 30B) were melt blended in a twin‐screw extruder. Nanocomposites of 2.5, 5 and 7.5% by weight were produced. Wide angle X‐ray scattering was used to ascertain the degree of layer swelling that could be attributed to the intercalation of polymer chains into the interlayer of the silicates. Transmission electron microscopy was used to analyze the dispersion and extent of exfoliation of the layered silicates in the polymer matrix. All nanocomposites were found to have mixed intercalated/exfoliated morphologies. Both storage and loss moduli and complex viscosity showed improvement at all frequencies tested with increase in silicate loading. Terminal zone behavior was also shown to disappear gradually with silicate content. Increase in silicate loading had caused the divergence of viscosity profile from low‐frequency Newtonian plateau to non‐Newtonian slope corresponding to a possible finite yield stress. The gradual disappearances of terminal zone and Newtonian homopolymer‐like characteristics with silicate loading were attributed to the formation of lattice spanning three‐dimensional network structures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2127–2135, 2006     

Morphology, rheology and dynamic mechanical properties of PP/EVA/clay nanocomposites

This paper reports on morphology, rheology and dynamic mechanical properties of polypropylene (PP)/ethylene vinyl acetate (EVA) copolymer/clay nanocomposite system prepared via a single step melt compounding process using a twin screw micro-compounder. Scanning electron microscopic (SEM) investigations revealed that the dispersed phase droplet size was reduced with incorporation of an organo-modified montmorillonite (OMMT). This reduction was more significant in presence of a maleated PP (PP-g-MAH) used as compatibilizer. Phase inversion in the compatibilized blends caused a further decrease in PP droplet size. The OMMT gallery spacing was higher in nanocomposites with EVA as matrix which could be attributed to higher tendency of OMMT nanoparticles towards EVA rather than PP. This enhanced tendency was confirmed by rheological analysis too. Transmission electron microscopy (TEM) results also showed that the majority of OMMT nanoparticles were localized on the interface and within EVA droplets. According to dynamic mechanical analysis, the compatibilized nanocomposites showed higher storage and loss moduli due to better dispersion of OMMT layers. The modulus enhancement of nanocomposites as a function of OMMT volume fraction was modeled by Halpin-Tsai’s-Nielsen expression of modulus for nanocomposites. The results of modeling suggested that the aspect ratio of the intercalated OMMT, in the form of Einstein coefficient (K _E), plays a determining role in the modulus enhancement of nanocomposites.