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Organoclay
Terms modified by Organoclay Selected AbstractsThe effect of polyoxypropylene-montmorillonite intercalates on polymethylmethacrylatePOLYMER COMPOSITES, Issue 1 2009Nehal Salahuddin Polymethylmethacrylate (PMMA)-layered silicate nanocomposites have been prepared by in situ polymerization of commercial type of methylmethacrylate monomer (MMA), for denture base material, into organoclay. Organoclay was prepared through an ion exchange process between sodium cations in montmorillonite and NH3+ groups in polyethertriamine hydrochloride and polyoxypropylene triamine hydrochloride with different molecular weight (5000, 440). X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been used to investigate the structure of the resulting composites. Both intercalated and exfoliated nanocomposites were obtained depending on the type and amount of organoclay. The thermal decomposition temperatures of the nanocomposites were found to be higher than that of pristine polymer. PMMA was strongly fixed to inorganic surfaces, due to cooperative formation of electrostatic bonding between NH3+ group and negatively charged surface of layered silicate and amide linkage between PMMA and polyethertriamine or polyoxypropylene triamine. The effect of the organoclay on the hardness, toughness, tensile stress, and elongation at break of the polymer was studied and was compared with pristine polymer. The hardness and Izod impact strength of PMMA-organoclay nanocomposites were enhanced with the inclusion of clay. Tensile properties appear to be enhanced at certain organoclay content. However, the water absorption is slightly higher than the pristine PMMA. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Organoclay,natural rubber nanocomposites synthesized by mechanical and solution mixing methodsPOLYMER INTERNATIONAL, Issue 11 2004MA López-Manchado Abstract This investigation describes two methods to obtain rubber composites based on natural rubber (NR) and organophilic layered silicates. In order to improve the exfoliation and compatibilization of the organoclays with the rubber matrix, a new approach which involves swelling of the organoclays with an elastomer solution prior to compounding has been used. The effect of the addition during swelling of a coupling agent, namely bis(trietoxysilylpropyl)tetrasulfan (TESPT), on the behaviour of the composites was also investigated. The results show that a low amount of organoclay (10 phr) significantly improves the properties of natural rubber. This suggests a strong rubber,organoclay interaction which is attributed to a high degree of rubber intercalation into the nanosilicate galleries, as was confirmed from X-ray diffraction. In addition, an ulterior improvement in the properties of the nanocomposites prepared by solution mixing is clearly observed, due to the better filler,rubber compatibility. An even further increase in the properties is observed by treating the silicate with a silane coupling agent. The silane functional groups modify the clay surface, thus reducing the surface energy, and consequently improving the compatibility with the rubber matrix. Copyright © 2004 Society of Chemical Industry [source] A flammability performance comparison between synthetic and natural clays in polystyrene nanocompositesFIRE AND MATERIALS, Issue 4 2005Alexander B. Morgan Abstract Polymer-clay nanocomposites are a newer class of flame retardant materials of interest due to their balance of mechanical, thermal and flammability properties. Much more work has been done with natural clays than with synthetic clays for nanocomposite flammability applications. There are advantages and disadvantages to both natural and synthetic clay use in a nanocomposite, and some of these, both fundamental and practical, will be discussed in this paper. To compare natural and synthetic clays in regards to polymer flammability, two clays were used. The natural clay was a US mined and refined montmorillonite, while the synthetic clay was a fluorinated synthetic mica. These two clays were used as inorganic clays for control experiments in polystyrene, and then converted into an organoclay by ion exchange with an alkyl ammonium salt. The organoclays were used to synthesize polystyrene nanocomposites by melt compounding. Each of the formulations was analysed by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Flammability performance was measured by cone calorimeter. The data from the experiments show that the synthetic clay does slightly better at reducing the heat release rate (HRR) than the natural clay. However, all the samples, including the inorganic clay polystyrene microcomposites, showed a decreased time to ignition, with the actual nanocomposites showing the most marked decrease. The reason for this is postulated to be related to the thermal instability of the organoclay (via the quaternary alkyl ammonium). An additional experiment using a more thermally stable organoclay showed a time to ignition identical to that of the base polymer. Finally, it was shown that while polymer-clay nanocomposites (either synthetic or natural clay based) greatly reduce the HRR of a material, making it more fire safe, they do not provide ignition resistance by themselves, at least, at practical loadings. Specifically, the cone calorimeter HRR curve data appear to support that these nanocomposites continue to burn once ignited, rather than self-extinguish. Copyright © 2004 John Wiley & Sons, Ltd. [source] Comparison of polyamide 66,organoclay binary and ternary nanocompositesADVANCES IN POLYMER TECHNOLOGY, Issue 3 2009Miray Mert Abstract Polyamide 66,Lotader® 2210 blends (95/5 w/w), polyamide 66,Cloisite® 15A binary nanocomposites (98/2 w/w), and polyamide 66,Lotader® 2210,Cloisite® 15A ternary nanocomposites (93/5/2 w/w) were prepared by twin-screw extrusion, and the changes in mechanical properties, morphology, and flow properties of the materials prepared by different mixing sequences were investigated in this study. Lotader® 2210, which is a random terpolymer of ethylene, butyl acrylate, and maleic anhydride, was used as the impact modifier for polyamide 66 blends as well as polyamide 66 based nanocomposites. The best dispersion level, highest mechanical properties, highest viscosity values, and smallest elastomeric domain sizes were obtained for the mixing sequence in which all the components forming the ternary nanocomposites were compounded simultaneously. Incorporation sequence of either the organoclay or the impact modifier into the polymeric matrix was varied in the other mixing sequences, and this resulted in poorer distribution of the organoclay platelets and elastomeric domains in the matrix owing to insufficient shear intensity applied on the components in a single extrusion step. Toughness values of the ternary nanocomposites were improved compared with the binary nanocomposites upon addition of the impact modifier into polymer,organoclay combination. It was concluded that the compounding sequence of the components plays a significant role in the dispersion of organoclay and the properties of the nanocomposites, because it directly affects the interaction between the different phases. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:155,164, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20158 [source] Effect of the organoclay preparation on the extent of intercalation/exfoliation and barrier properties of polyethylene/PA6/montmorillonite nanocompositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2010Eleonora Erdmann Abstract Nanocomposites of HDPE matrix and 3 wt % organoclay/PA6 discontinuous phase were prepared in a mixer chamber. These nanocomposites of organoclay, PA6, and HDPE were characterized by X-ray diffraction, scanning electron and transmission electron microscopy (SEM and TEM). Barrier properties were determined by cyclohexane pervaporation and solubility. The results show that the degree of exfoliation and/or intercalation and the barrier properties depend on a combination of the proper chemical treatment and optimized processing in these polyethylene-organoclays nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Polyamide 66 binary and ternary nanocomposites: Mechanical and morphological propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2010Miray Mert Abstract Polyamide 66 (PA 66)/impact modifier blends and polyamide/organoclay binary and PA 66/organoclay/impact modifier ternary nanocomposites were prepared by the melt-compounding method, and the effects of the mixing sequences on the morphology and mechanical and flow properties were investigated. Lotader AX8840 and Lotader AX8900 were used as impact modifiers. The concentrations of the impact modifiers and the organoclay (Cloisite 25A) were maintained at 2 and 5 wt %, respectively. Both the binary and ternary nanocomposites displayed high tensile strength and Young's modulus values compared to the PA 66/impact modifier blends. Decreases occurred in the strength and stiffness of the binary nanocomposites upon incorporation of the elastomeric materials into the polymeric matrix. In general, the mixing sequence in which all three ingredients were added simultaneously and extruded twice (the All-S mixing sequence) exhibited the most enhanced mechanical properties in comparison with the mixing sequences in which two of the components were extruded in the first extrusion step and the third ingredient was added in the second extrusion step. The mechanical test results were in accordance with the organoclay dispersion. The impact strength was highly affected by the elastomeric domain sizes, interdomain distances, interfacial interactions, and organoclay delamination. The smallest elastomeric domain size was obtained for the All-S mixing sequence, whereas the elastomeric domain sizes of the other mixing sequences were quite close to each other. Drastic variations were not observed between the melt viscosities of the ternary nanocomposites prepared with different mixing sequences. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Morphology and thermal behavior of organo-bentonite clay/poly(styrene- co -methacrylic acid)/poly(isobutyl methacrylate- co -4-vinylpyridine) nanocompositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2009Abderrahmane Habi Abstract Poly(styrene- co -methacrylic acid) containing 29 mol % of methacrylic acid (SMA-29) and poly(isobutyl methacrylate- co -4-vinylpyridine) containing 20 mol % of 4-vinylpyridine (IBM4VP-20) were synthesized, characterized, and used to elaborate binary and ternary nanocomposites of different ratios with a 3% by weight hexadecylammonium-modified bentonite from Maghnia (Algeria) by casting method from tetrahydrofuran (THF) solutions. The morphology and the thermal behavior of these binary and ternary elaborated nanocomposites were investigated by X-ray diffraction, scanning electron microscopy, FTIR spectroscopy, differential scanning calorimetry, and thermogravimetry. Polymer nanocomposites and nanoblends of different morphologies were obtained. The effect of the organoclay and its dispersion within the blend matrix on the phase behavior of the miscible SMA29/IBM4VP20 blends is discussed. The obtained results showed that increasing the amount of SMA29 in the IBM4VP20/SMA29 blend leads to near exfoliated nanostructure with significantly improved thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Influence of compatibilizer on notched impact strength and fractography of HDPE,organoclay compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2009Waraporn Rattanawijan Abstract The focus of this study was the notched impact property of high-density polyethylene (HDPE),organoclay composites and the resultant morphology of impact-fractured surfaces. Composites with a different organoclay content and degree of organoclay dispersion were compared with neat HDPE under identical conditions. The degree of organoclay dispersion was controlled through the use of a compatibilizer, maleic anhydride grafted polyethylene. It was found that the addition of organoclay can slightly increase the elastic modulus and notched impact strength of the composite. When the level of organoclay dispersion was improved by using compatibilizer, elastic modulus and toughness further increased. A significant increase in yield strength was also notable. The presence of organoclay was found to suppress strain hardening of the matrix during tensile testing. The impact-fractured surfaces of failed specimens were studied with scanning electron microscopy. The micromechanism for the increased toughness of HDPE,organoclay composites was discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Thermal stability of surfactants with amino and imido groups in poly(ethylene terephthalate)/clay compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Xuepei Yuan Abstract Effects of thermal stability of surfactants with amino and imido groups on thermal properties of poly(ethylene terephthalate) (PET)/clay composites were studied. The imidosilane surfactant was synthesized successfully from the imide reaction between amino silane and phthalic anhydride. TGA shows that imidosilane decomposition behaviors have two major stages according to the degradations of different functional groups. After melt extrusion, the decomposition of amino functional groups in amino surfactants decreases the thermal stability of organoclay and accelerates the degradation behaviors of PET composites. Because of the enhanced thermal stability of imidosilane surfactants, PET/imido-palygorskite (PT) composites represent enhanced thermal stability, good dispersion and low thermal expansion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Colorless polyimide nanocomposite films: Thermomechanical properties, morphology, and optical transparencyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Hyo-Seong Jin Abstract Polyimide (PI)/organoclay hybrid films were prepared by the solution intercalation method, using dodecyltriphenylphosphonium-mica (C12PPh-Mica) as the organoclay. The variations with organoclay content of the thermomechanical properties, morphology, and optical transparency of the hybrids were examined for concentrations from 0 to 1.0 wt %. For low clay contents (, 0.5 wt %), the clay particles are better dispersed in the matrix polymer, without the formation of large agglomerates of particles, than they are for high clay contents. However, agglomerated structures form and become denser in the PI matrix for clay contents , 0.75 wt %. This is in agreement with the observed trends in the thermomechanical properties and the optical transparency, which worsen drastically when the clay content of the C12PPh-Mica/PI hybrids reaches 0.75 wt %. However, when the amount of organoclay in the hybrid is 0.75 wt %, the initial modulus of the hybrid film is at its maximum value. The PI hybrid films were found to exhibit excellent optical transparencies and to be almost colorless. It was found, however, that the transparency decreases slightly with increases in the organoclay content because of agglomeration of the clay particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Fiber breakage and dispersion in carbon-fiber-reinforced nylon 6/clay nanocompositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Hu Zhou Abstract In this paper, short carbon-fiber-reinforced nylon 6/clay nanocomposites are prepared via melt compounding, and fiber breakage and dispersion during processing are studied. The influences of clay and processing conditions on fiber breakage and dispersion are taken into consideration. It is found that the presence of organoclay can improve fiber dispersion, which is due to dispersion at the nanoscale of exfoliated clay sheets with large aspect ratio. The bimodal distribution of fiber length is observed in fiber-reinforced nanocomposites, which is similar to that in conventional fiber-reinforced composites. The improvement of fiber breakage at moderate organoclay loadings is also observed, which is ascribed to the rheological and lubricating effects induced by organoclay. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source] Synthesis and characterization of poly(butylene terephthalate)/mica nanocomposite fibers via in situ interlayer polymerizationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2007Jin-Hae Chang Abstract Intercalated nanocomposites consisting of poly(butylene terephthalate) (PBT) incorporated between mica layers were synthesized from dimethyl terephthalate (DMT) and 1,4-butanediol (BD) by in situ interlayer polymerization. PBT nanocomposites of varying organoclay content were melt-spun to produce monofilaments. The samples were characterized using wide angle X-ray diffraction, electron microscopy, thermal analysis, and tensile testing. Some of the clay particles were found to be well dispersed in the PBT matrix, but other clay particles were agglomerated at a size level greater than approximately 20 nm. The glass transition temperatures (Tg) and the thermal degradation properties (TDi) of undrawn PBT hybrid fibers were found to improve with increases in the clay content. At draw ratio (DR) = 1, the ultimate tensile strengths of the hybrid fibers increased with the addition of clay up to a critical content and then decreased. However, the initial moduli monotonically increased with increases in the amount of organoclay in the PBT matrix. The ultimate strengths were found to decrease linearly with increases in DR from 1 to 18. In contrast to the trend for the tensile strengths, the initial moduli of the hybrid fibers increased only slightly with increases in DR up to 18. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Mechanical and morphological properties of organic,inorganic, hybrid, clay-filled, and cyanate ester/siloxane toughened epoxy nanocompositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2007S. Nagendiran Abstract Organic,inorganic hybrids involving cyanate ester and hydroxyl-terminated polydimethylsiloxane (HTPDMS) modified diglycidyl ether of bisphenol A (DGEBA; epoxy resin) filled with organomodified clay [montmorillonite (MMT)] nanocomposites were prepared via in situ polymerization and compared with unfilled-clay macrocomposites. The epoxy-organomodified MMT clay nanocomposites were prepared by the homogeneous dispersion of various percentages (1,5%), and the resulting homogeneous epoxy/clay hybrids were modified with 10% HTPDMS and ,-aminopropyltriethoxysilane as a coupling agent in the presence of a tin catalyst. The siliconized epoxy/clay prepolymer was further modified separately with 10% of three different types of cyanate esters, namely, 4,4,-dicyanato-2,2,-diphenylpropane, 1,1,-bis(3-methyl-4-cyanatophenyl) cyclohexane, and 1,3-dicyanato benzene, and cured with diaminodiphenylmethane as a curing agent. The reactions during the curing process between the epoxy, siloxane, and cyanate were confirmed by Fourier transform infrared analysis. The results of dynamic mechanical analysis showed that the glass-transition temperatures of the clay-filled hybrid epoxy systems were lower than that of neat epoxy. The data obtained from mechanical studies implied that there was a significant improvement in the strength and modulus by the nanoscale reinforcement of organomodified MMT clay with the matrix resin. The morphologies of the siloxane-containing, hybrid epoxy/clay systems showed heterogeneous character due to the partial incompatibility of HTPDMS. The exfoliation of the organoclay was ascertained from X-ray diffraction patterns. The increase in the percentage of organomodified MMT clay up to 5 wt % led to a significant improvement in the mechanical properties and an insignificant decrease in the glass-transition temperature versus the unfilled-clay systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Effect of dispersion state of organoclay on cellular foam structure and mechanical properties of ethylene vinyl acetate copolymer/ethylene-1-butenecopolymer/organoclay nanocomposite foamsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Keun-Wan Park Abstract In this study, our goal is to obtain lower density of ethylene-vinyl acetate copolymer (EVA)/ethylene-1-butene copolymer (EtBC) foams without sacrificing mechanical properties. For this purpose EVA/EtBC/organoclay (Cloisite 15A, Closite 30B) nanocomposite foams were prepared. To investigate the effect of compatibilizer on the dispersion state of organoclay in cellular foam structure and mechanical properties of the EVA/EtBC/organoclay foams composites were prepared with and without maleic anhydride grafted EtBC (EtBC-g-MAH). The dispersion of organoclay in EVA/EtBC/organocaly foams was investigated by X-ray diffraction and transmission electron microscopy. The EVA/EtBC nanocomposite foamswith the compatibilzer, especially EVA/EtBC/Cloisite 15A/EtBC-g-MAH foams displayed more uniform dispersion of organoclay than EVA/EtBC nanocomposite foams without the compatibilzer. As a result, EVA/EtBC/Cloisite 15A/EtBC-g-MAH foams have the smallest average cell size and highest 100% tensile modulus followed by EVA/EtBC/Cloisite 30B/EtBC-g-MAH foams. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3879,3885, 2007 [source] Influence of Layered Silicate on the Self-Crosslinking of Polychloroprene and Carboxylated Nitrile RubberMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 2 2009Amit Das Abstract The effect of organically modified clay on the properties of self-crosslinkable carboxylated acrylonitrile-butadiene rubber (XNBR) and polychloroprene rubber (CR) blend is studied. Results of blends produced without crosslinking agents are compared with conventional sulphur cured compounds. Sulphur cured blends exhibit improved physical properties after the incorporation of organophilic-modified clay. In contrast, the self-crosslinked blends do not show any reinforcement after the incorporation of the organoclay. XRD spectra show an intercalation of polymer chain into the gallery gap of the clay in both cases. ATR-IR, DMA and SEM studies of these composites confirm that organoclay particles constrain the self-crosslinking mechanism. The influence of the organoclay on the crystallisation of CR is also shown. [source] Comparative Characterization of PP Nano- and Microcomposites by In-Mold Shrinkage Measurements and Structural CharacteristicsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 6 2007Rodolfo Revilla-Díaz Abstract Poly(propylene)-clay nanocomposites and poly(propylene) containing conventional inorganic fillers such as calcium carbonate (CaCO3) and glass fiber were used in a comparative study focusing on dimensional stability, structure, mechanical and thermal properties. Micro- and nanocomposites were prepared by melt blending in a twin-screw extruder. The relative influence of each filler was observed from dimensional stability measurements and structural analysis by WAXD, TEM, and thermal and mechanical properties. At equal filler loadings, PP/clay nanocomposites exhibit an improvement in dimensional stability and were the only composites capable of reduced shrinkage in both in-flow and cross-flow directions. The flexural modulus of PP increased nearly 20% by compounding with 4% organoclay, as compared to a similar performance obtained by compounding with 10 wt.-% of CaCO3 or approximately 6 wt.-% of glass fiber. The HDT and thermal stability of PP were enhanced by using nanoclay as filler. [source] Effect of Organic Modification on the Compatibilization Efficiency of Clay in an Immiscible Polymer BlendMACROMOLECULAR RAPID COMMUNICATIONS, Issue 20 2005Suprakas Sinha Ray Abstract Summary: This communication describes the effect of organic modifier miscibility with the matrices, and the effect of the initial interlayer spacing of the organoclay, on the overall morphology and properties of an immiscible polycarbonate/poly(methyl methacrylate) blend. By varying the organic-modifier-specific interactions with the blend matrices at the same time as changing the initial interlayer spacing of the organoclay, different levels of compatibilization were revealed. The evidence for the interfacial compatibilization of the organoclay was assessed by scanning electron microscopy observations and was supported by differential scanning calorimetry analyses. The effect on the level of clay exfoliation was also examined. Differential scanning calorimetry scans of virgin, montmorillonite, and various organically modified montmorillonite-compatibilized 40PC/60PMMA blends [source] Co-continuous Polyamide 6 (PA6)/Acrylonitrile-Butadiene-Styrene (ABS) NanocompositesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2005Yongjin Li Abstract Summary: Polyamide 6 (PA6)/acrylonitrile-butadiene-styrene (ABS) (40/60 w/w) nanocomposites with a novel morphology were prepared by the melt mixing of PA6, ABS and organoclay. The blend nanocomposites had a co-continuous structure, in which both PA6 and styrene-acrylonitrile (SAN) were continuous phases. It was found that the toughening rubber particles were only located in the SAN phase and the strengthening clay platelets were selectively dispersed in the PA6 phase. The co-continuous nanocomposites showed greatly improved mechanical properties over the whole temperature range when compared with the same blend sample without clay. Schematic diagram for the co-continuous ABS/PA6 blend nanocomposite. [source] The Role of Functional Group on the Exfoliation of Clay in Poly(L -lactide)MACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2005Guang-Xin Chen Abstract Summary: A new method was attempted to improve the interaction between poly(L -lactide) (PLLA) with a commercially available organoclay, Cloisite 25A (C25A), which was functionalized with (glycidoxypropyl)trimethoxysilane to introduce epoxy groups, and is referred to as twice-functionalized organoclay (TFC). Tethering PLLA molecules to the epoxy groups on the surface of the TFC was attempted by melt compounding. X-Ray diffraction and transmission electron microscopy images showed that fully exfoliated PLLA/TFC nanocomposites were prepared successfully. Transmission electron micrographs of the PLLA composites of the three clays used here. [source] Morphology of Polymer/Clay Latex Particles Synthesized by Miniemulsion Polymerization: Modeling and Experimental ResultsMACROMOLECULAR REACTION ENGINEERING, Issue 6-7 2010Matej Mi Abstract BA/MMA (90:10,wt.-%) were copolymerized in the presence of two different organomodified clays (C30B and CMA16) and 1.6,2.6,wbm.-% surfactants. The effect of the compatibility of the organoclay in the monomer mixture on the morphology of hybrid polymer/clay particles was determined using TEM. The resulting morphologies were compared with the prediction of a Monte-Carlo simulation that determined the equilibrium morphology of monomer/clay hybrid miniemulsion droplets. The model predicted encapsulated morphologies only when the organoclay presented low clay/monomer and high clay/water interfacial tensions. C30B and CMA16 did not fulfill these conditions and provided a preferential surface location of the platelets on the polymer/water interphase as predicted by the model. [source] Biodegradable nanocomposites from maleated polycaprolactone/soy protein isolate blend with organoclay: Preparation, characterization, and propertiesPOLYMER COMPOSITES, Issue 6 2009Abhisek Sasmal New biobased, eco-friendly nanocomposites were prepared from maleated polycaprolactone/soy protein isolate blend (50/50 wt/wt) with organo-modified clay by melt compounding. The XRD, TEM, tensile, DMTA, and rheological properties of the nanocomposites were investigated. X-ray diffraction and transmission electron microscopy analysis revealed that the intercalated nanocomposite is formed and the silicate layers of the clay are uniformly dispersed at a nanometer scale in the polymer matrix. There is a great enhancement in tensile and dynamic mechanical properties of the nanocomposites. Rheological study revealed that the nanocomposite exhibits strong shear thinning behavior and clay particles form network in the melted state of the composites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Investigation of oxygen barrier properties of organoclay/HDPE/EVA nanocomposite films prepared using a two-step solution methodPOLYMER COMPOSITES, Issue 6 2009S.M. Reza Dadfar In this article, oxygen barrier properties of nanocomposite films composed of organoclay (OC), high-density polyethylene (HDPE), and ethylene vinyl acetate (EVA) copolymer have been investigated. The nanocomposite films whose EVA forms a dominant fraction were prepared using the solution method. The dispersion of the OC in the HDPE/EVA blend was improved through taking two-step procedure in the preparation of nanocomposite. First, the OC and EVA were dissolved in chloroform. Then, the resulting product, after evaporating most of the solvent, along with HDPE was dissolved in xylene. The obtained nanocomposite films underwent a number of tests in order to examine their barrier properties including X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that OC/HDPE/EVA nanocomposites are intercalated and partially exfoliated. Furthermore, from the TEM micrographs, the organoclay experimental aspect ratio was found. Also, the O2 permeability through the films was evaluated, which showed that adding both OC and HDPE to EVA leads to a remarkable increase in the barrier properties of EVA films. Finally, by using the gas permeation results and existing permeation theories, the organoclay theoretical aspect ratio was predicted. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Preparation of photodegradable polypropylene/clay composites based on nanoscaled TiO2 immobilized organoclayPOLYMER COMPOSITES, Issue 5 2009Xiangfu Meng Photodegradable polypropylene (PP) composites were prepared via melting blending using PP and titanium dioxide (TiO2) immobilized organically modified montmorillonite (organoclay). TiO2 immobilized organoclay (TiO2 -OMT) was synthesized by immobilizing anatase TiO2 nanoparticles on organically modified clay via sol,gel method. The structure and morphology of TiO2 -OMT were characterized by XRD and scanning electron microscope (SEM), which showed that anatase TiO2 nanoparticles with the size range of 8,12 nm were uniformly immobilized on the surface of organoclay layers. Diffuse reflection UV,vis spectra revealed TiO2 -OMT had similar absorbance characters to that of commercial photocatalyst, Degussa P25. The solid-phase photocatalytic degradation of PP/TiO2 -OMT composites was investigated by FTIR, DSC, GPC and SEM. The results indicated that TiO2 -OMT enhanced the photodegradation rate of PP under UV irradiation. This was due to that immobilization of TiO2 nanoparticles on organoclay effectively avoided the formation of aggregation, and thereby increased the interface between PP and TiO2 nanoparticles. After 300 h irradiation, the average molecular weight was reduced by two orders of magnitude. This work presented a promising method for preparation of environment-friendly polymer nanocomposites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers. [source] Preparation and characterization of nylon 6/organoclay nanocomposite filament fibersPOLYMER COMPOSITES, Issue 3 2009Kap Jin Kim A series of nylon 6 (NY6)/organoclay nanocomposites were prepared via in situ polymerization of ,-caprolactam in the presence of 1,2-aminododecanoic acid-intercalated montmorillonite (ADA-MMT) organoclay (1,5 wt%) using 6-aminocaproic acid as polymerization catalyst. The extent of organoclay dispersion in NY6 matrix was analyzed using WAXD and SEM measurements. DSC studies revealed marginal shift in melting and melt-crystallization peaks toward lower temperature with increasing clay content. Melt viscosity studies for NY6/ADA-MMT exhibited higher shear-thinning behavior than neat NY6 probably due to the slip between NY6 matrix and exfoliated organoclay platelets during shear flow. The prepared nanocomposites were melt-spun and studied for their property improvements against varying clay content, draw ratios, and annealing conditions. Birefringence and sonic velocity values increased initially at lower draw ratios (,2.5) due to increased orientation of molecular chains along the drawing direction but saturated at higher draw ratio (3.0) for all the samples. At the same draw ratio; compared to neat NY6, NY6/organoclay fibers showed increased chain orientation along the drawing direction which can be attributed to the "tethering effect" of organoclay on NY6 matrix. The initial modulus and stress at break were sensitive to factors such as draw ratio, clay content, and annealing conditions. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] The effect of polyoxypropylene-montmorillonite intercalates on polymethylmethacrylatePOLYMER COMPOSITES, Issue 1 2009Nehal Salahuddin Polymethylmethacrylate (PMMA)-layered silicate nanocomposites have been prepared by in situ polymerization of commercial type of methylmethacrylate monomer (MMA), for denture base material, into organoclay. Organoclay was prepared through an ion exchange process between sodium cations in montmorillonite and NH3+ groups in polyethertriamine hydrochloride and polyoxypropylene triamine hydrochloride with different molecular weight (5000, 440). X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been used to investigate the structure of the resulting composites. Both intercalated and exfoliated nanocomposites were obtained depending on the type and amount of organoclay. The thermal decomposition temperatures of the nanocomposites were found to be higher than that of pristine polymer. PMMA was strongly fixed to inorganic surfaces, due to cooperative formation of electrostatic bonding between NH3+ group and negatively charged surface of layered silicate and amide linkage between PMMA and polyethertriamine or polyoxypropylene triamine. The effect of the organoclay on the hardness, toughness, tensile stress, and elongation at break of the polymer was studied and was compared with pristine polymer. The hardness and Izod impact strength of PMMA-organoclay nanocomposites were enhanced with the inclusion of clay. Tensile properties appear to be enhanced at certain organoclay content. However, the water absorption is slightly higher than the pristine PMMA. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Preparation and characterization of polypropylene/solid-state organomodified montmorillonite nanocompositesPOLYMER COMPOSITES, Issue 4 2008Sun Yu-hai A novel organomodified montmorillonite prepared by solid-state method and its nanocomposites with polypropylene were studied. The interaction between modifying agent and montmorillonite was investigated by X-ray diffraction (XRD) analysis, contact angle determination, and Fourier-transform infrared spectroscopy. The results showed that the modifying agent behaves as an effective intercalating agent, enlarging the interlayer spacing of montmorillonite and making montmorillonite more hydrophobic. Polypropylene/solid-state organomodified montmorillonite composites were prepared by melt-mixing method. The dispersion of the silicates was investigated by XRD analysis and transmission electron microscopy. It was found that the nanocomposites are formed with solid-state organomodified montmorillonite and polypropylene. The thermogravimetric analysis and differential scanning calorimetry results showed that the organoclay could enhance the thermal stability and decrease the relative crystallinity of polypropylene. Mechanical and rheological tests indicated that the organoclay improves the mechanical properties but has no obvious effect on rheological properties of polypropylene. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Preparation of exfoliated high-impact polystyrene/MMT nanocomposites via in situ polymerization under controlling viscosity of the reaction mediumPOLYMER COMPOSITES, Issue 2 2008Periyayya Uthirakumar Exfoliated high-impact polystyrene (HIPS)/montmorillonite (MMT) nanocomposites were prepared via in situ polymerization of styrene in the presence of polybutadiene, using an intercalated cationic radical initiator-MMT hybrid (organoclay). In the solution polymerization in toluene, the silicate layers of the clay were well exfoliated, due to the low extra-gallery viscosity that can facilitate the diffusion of styrene monomers into the clay layers during the polymerization. The exfoliated HIPS/MMT nanocomposites were also successfully prepared by controlling the viscosity of the reaction medium with prolong swelling of the organoclay in styrene, prior to bulk polymerization. The HIPS/MMT nanocomposites, obtained from bulk polymerization, exhibited a significant improvement in thermal stability, compared to those obtained from solution polymerization as well as the pure polymer counterparts. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers [source] Melt processing and characterization of multicomponent polymeric nanocomposites containing organoclayPOLYMER COMPOSITES, Issue 3 2007M. Letuchi Nylon 6 (Ny)/polypropylene (PP)/maleated polypropylene (PP- g -MA)/organoclay/wollastonite composites were prepared by melt processing. The polymers' composition was kept constant ([70PP/30Ny]/4PP- g -MA). Melt compounding was conducted using a twin-screw extruder in three different methods: (1) simultaneous incorporation of the components into the compounding equipment, (2) preparation of [Ny6/clay] concentrate, and then in a second step, mixing the other components with the concentrate, and (3) mixing of PP with wollastonite and clay followed by the addition of Ny6 and PP- g -MA in the second step. Injection-molded specimens were characterized in tension, scanning electron microscopy, X-ray diffraction (XRD), and differential scanning calorimetry. The sequence of component addition greatly influences the structure and properties of the composites. Enhanced mechanical properties were achieved when the two-step mixing procedure was used for the PP/Ny6/PP- g -MA/clay system (method 2) and also for the PP/Ny6/PP- g -MA/clay/wollastonite system (method 3). The XRD pattern of the PP/Ny6/PP- g -MA/clay nanocomposites produced by the two-step mixing method does not show a characteristic basal reflection of the pristine organoclay, indicating a predominately exfoliated structure of clay. POLYM. COMPOS., 28:417,424, 2007. © 2007 Society of Plastics Engineers [source] Reactive extrusion of poly(ethylene terephthalate),(ethylene/methyl acrylate/glycidyl methacrylate),organoclay nanocompositesPOLYMER COMPOSITES, Issue 2 2007Elif Alyamac This study was conducted to investigate the effects of component concentrations and addition order of the components on the final properties of ternary nanocomposites composed of poly(ethylene terephthalate), organoclay, and an ethylene,methyl acrylate,glycidyl methacrylate (E-MA-GMA) terpolymer acting as an impact modifier for PET. In this context, first, the optimum amount of the impact modifier was determined by melt compounding binary PET-terpolymer blends in a corotating twin-screw extruder. The amount of the impact modifier (5 wt%) resulting in the highest Young's modulus and moderate elongation at break was selected owing to its balanced mechanical properties. Thereafter, by using 5 wt% terpolymer content, the effects of organically modified clay concentration and addition order of the components on the properties of ternary nanocomposites were systematically investigated. Mechanical testing revealed that different addition orders of the materials significantly affected the mechanical properties. Among the investigated addition orders, the best sequence of component addition (PI-C) was the one in which poly(ethylene terephthalate) was first compounded with E-MA-GMA. Later, this mixture was compounded with the organoclay in the subsequent run. In X-ray diffraction analysis, extensive layer separation associated with delamination of the original clay structure occurred in PI-C and CI-P (Clay + Impact Modifier followed by PET) sequences with both 1 and 3 wt% clay contents. X-ray diffraction patterns showed that at these conditions exfoliated structures resulted as indicated by the disappearance of any peaks due to the diffraction within the consecutive clay layers. POLYM. COMPOS., 28:251,258, 2007. © Society of Plastic Engineers [source] Polystyrene,organoclay nanocomposites prepared by melt intercalation, in situ, and masterbatch methodsPOLYMER COMPOSITES, Issue 3 2006Ulku Yilmazer In this study, polystyrene (PS)/montmorillonite nanocomposites were prepared by melt intercalation, in situ polymerization, and masterbatch methods. In the masterbatch method, as the first step, a high clay content composite of PS,organoclay (masterbatch) was prepared by in situ polymerization, and then the prepared masterbatch was diluted to desired compositions with commercial PS in a twin-screw extruder. The structure and mechanical properties of the nanocomposites were examined. X-ray diffraction (XRD) analysis showed that the d -spacing of the in situ formed nanocomposites increased from 32.9 Å for the organoclay powder to 36.3 and 36.8 Å respectively in nanocomposites containing 0.73 and 1.6 wt% organoclay, indicating intercalation. However, the d -spacing of the other prepared materials remained nearly unchanged when compared with pure organoclay powder. Thus, at these low clay contents, in situ formed nanocomposites showed the best improvement in mechanical properties including tensile, impact strength, and Young's modulus. In situ polymerization method did not prove to be efficient at high clay loadings in terms of intercalation and mechanical properties. At high clay loadings, the effects of the three methods in promoting mechanical properties were not significantly different from each other. POLYM. COMPOS., 27:249,255, 2006. © 2006 Society of Plastics Engineers [source] | |||||||||||||