Clay Nanocomposites (clay + nanocomposite)

Distribution by Scientific Domains
Distribution within Polymers and Materials Science

Kinds of Clay Nanocomposites

  • nylon clay nanocomposite


  • Selected Abstracts


    Poly(butylene terephthalate)/clay nanocomposite compatibilized with poly(ethylene- co -glycidyl methacrylate).

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008

    Abstract Poly(butylene terephthalate) (PBT)/clay nanocomposite was prepared by blending PBT and commercial modified montmorillonite clays via a extruder by using poly(ethylene- co -glycidyl methacrylate) (PEGMA) as a compatibilizer (PBT/PEGMA/Clay). PEGMA and clay were also blended with PBT to prepare PBT/PEGMA and PBT/Clay, respectively. The morphology was investigated by wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The clays were aggregated together and phase separation was observed in PBT/Clay. The clays were exfoliated in PBT/PEGMA/Clay. The equilibrium melting temperature was estimated by linear and nonlinear Hoffman-Weeks relation. The influence of the PEGMA and clay on the PBT crystallizable ability was also investigated by Avrami model and undercooling (difference between crystallization and equilibrium melting temperature). Hoffman-Lauritzen relation was used to estimate chain fold surface free energy. The exfoliated silicates cause a large number nucleus center to enhance the crystallization in PBT/PEGMA/Clay. The presence of PEGMA can react with the PBT and an increase in viscosity would reduce molecular mobility and crystallization in PBT/PEGMA. The aggregated clays have a confinement effect on the segmental motion of PBT and hinder the crystallization in PBT/Clay. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]


    Atomic Force Microscopic Observations on the Crystalline Morphology of Poly(ethylene naphthalate)/Clay Nanocomposites

    MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2007
    Yang Choo Chua
    Abstract Atomic force microscopic observations on an isothermally crystallized poly(ethylene naphthalate) (PEN)/clay nanocomposite suggest that the presence of nanoclay alters the lamellar organization in PEN mainly in three ways: 1) physically blocking the crystal growth front and creating wide amorphous regions within the spherulites, which may then be filled by secondary lamellae branching out from the primary lamellae of the same spherulite, or primary lamellae developed from other nearby nucleating centers; 2) inducing random twisting of lamellae; and 3) causing irregular crystallite growth fronts, with the protrusion of some leading lamellae. In particular, the physical hindrance imposed by clay tends to be more prevalent for lamellae that grow roughly perpendicular to the clay long axes. This may give rise to an anisotropic crystalline morphology if the clay layers exhibit a preferred orientation induced by flow. [source]


    Polypropylene nanocomposite film: A critical evaluation on the effect of nanoclay on the mechanical, thermal, and morphological behavior

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
    S. K. Sharma
    Abstract Polypropylene (PP)/clay nanocomposites prepared by melt blending technique using different percentages of clay with and without maleic anhydride grafted PP (MA-PP) were studied. The intercalated and exfoliated structure of nanocomposites was characterized by X-Ray Diffraction (XRD) and transmission electron microscopy (TEM). Because of the typical intercalated and exfoliated structure, the tensile modulus of the nanocomposites were improved significantly as compared to virgin PP. The viscoelastic behavior of the nanocomposites was studied by dynamical mechanical analysis (DMA) and the results showed that with the addition of treated clay to PP there was substantial improvement in storage modulus increases. The thermal stability and crystallization of the PP nanocomposites as studied by differential scanning calorimeter (DSC) and thermo gravimetric analysis (TGA) were also improved significantly compared to PP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]


    Catalytic activity during the preparation of PE/clay nanocomposites by in situ polymerization with metallocene catalysts

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009
    Paula Zapata
    Abstract Catalytic activity during the formation of polyethylene (PE)/clay nanocomposites by in situ polymerization with metallocenes was studied. Ethylene polymerization was carried out with the homogeneous metallocene in the presence of the clay particles and using the clay-supported metallocene catalyst. It was found that the catalytic activity of the homogeneous metallocene does not decrease in the presence of the clay particles and only a slight decrease of activity occurs using the clay-supported catalyst. The modification of the clay with MAO cocatalyst as well as its intercalation with ODA surfactant were found to play an important role during the in situ formation of the PE/clay nanocomposite. ODA-intercalated clay apparently facilitates the activation and monomer insertion processes on zirconocene centers located in internal sites of the clay structure. Although metallocene supported on MAO-treated clay exhibited somewhat lower catalytic activity than that supported directly on the ODA-intercalated clay, both systems favored the production of PE nanocomposites containing highly exfoliated clay particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]


    Polypropylene/clay nanocomposites prepared by in situ grafting-melt intercalation with a novel cointercalating monomer

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008
    Pingan Song
    Abstract Polypropylene (PP)/clay nanocomposites were prepared by melt-compounding PP with organomontmorillonite (OMT), using maleic anhydride grafted polypropylene (PP- g -MA) as the primary compatibilizer and N -imidazol- O -(bicyclo pentaerythritol phosphate)- O -(ethyl methacrylate) phosphate (PEBI) as the cointercalating monomer. X-ray diffraction patterns indicated that the larger interlayer spacing of OMT in PP was obtained due to the cointercalation monomer having a large steric volume and the d -spacing further increased with the addition of PP- g -MA, as evidenced by transmission electron microscopy. Thermogravimetric analysis revealed that the PEBI-containing PP nanocomposites exhibited better thermal stability than PEBI-free PP composites. Dynamic mechanical analysis demonstrated that the storage modulus was significantly enhanced, and the glass transition temperature (Tg) shifted slightly to low temperature with the incorporation of clay for PP/OMT hybrids. PEBI-containing PP/OMT composites gave a lower Tg value because of the strong internal plasticization effect of PEBI in the system. Cone calorimetry showed that the flame-retardancy properties of PP nanocomposites were highly improved with the incorporation of PEBI. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]


    Poly(styrene- b -tetrahydrofuran)/clay nanocomposites by mechanistic transformation

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2009
    Zuleyha Yenice
    Abstract Synthesis of poly(styrene- block -tetrahydrofuran) (PSt- b -PTHF) block copolymer on the surfaces of intercalated and exfoliated silicate (clay) layers by mechanistic transformation was described. First, the polystyrene/montmorillonite (PSt/MMT) nanocomposite was synthesized by in situ atom transfer radical polymerization (ATRP) from initiator moieties immobilized within the silicate galleries of the clay particles. Transmission electron microscopy (TEM) analysis showed the existence of both intercalated and exfoliated structures in the nanocomposite. Then, the PSt- b -PTHF/MMT nanocomposite was prepared by mechanistic transformation from ATRP to cationic ring opening polymerization (CROP). The TGA thermogram of the PSt- b -PTHF/MMT nanocomposite has two decomposition stages corresponding to PTHF and PSt segments. All nanocomposites exhibit enhanced thermal stabilities compared with the virgin polymer segments. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2190,2197, 2009 [source]


    Poly(propylene)/Clay Nanocomposites Prepared by Reactive Compounding with an Epoxy Based Masterbatch

    MACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005
    Ling Chen
    Abstract Summary: Poly(propylene) (PP)/clay nanocomposites have been prepared via a novel reactive compounding approach, in which an epoxy based masterbatch consisting of 20 wt.-% clay was introduced to poly(propylene) with the aid of a maleic anhydride grafted PP (MAPP). The masterbatch was prepared using a recently developed "slurry compounding" technique. After melt compounding, most clay particles have been exfoliated and dispersed into small stacks with several clay layers. WAXD data shows that the dispersion of clay is better at low clay content or high MAPP content. Due to the novelty of the preparation process and complication of the system, the tensile properties of nanocomposites exhibit some unique tendencies with varying the content of MAPP or masterbatch. It is believed that the yield strength and Young's modulus can be dramatically improved after minimizing the excess of unreacted epoxy and optimizing the dispersion of clay. TEM micrograph of PP/clay nanocomposites prepared with epoxy based masterbatch. [source]


    Intercalated Polycarbonate/Clay Nanocomposites: Nanostructure Control and Foam Processing

    MACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2003
    Masaki Mitsunaga
    Abstract Intercalated polycarbonate (PC)/clay nanocomposites (PCCN)s have been prepared successfully through the melt intercalation method in the presence of a compatibilizer. The internal structure and morphology of the PCCNs has been established by using wide-angle X-ray diffraction (WAXD) analyses and transmission electron microscopic (TEM) observations. The morphology of these nanocomposites and degradation of the PC matrix after nanocomposites preparation can be controlled by varying surfactants used for the modification of clay and compatibilizer. The intercalated PCCNs exhibited remarkable improvements of mechanical properties when compared with PC without clay. We also discuss foam processing of one representative PCCN using supercritical CO2 as a foaming agent. TEM bright field image of intercalated polycarbonate/synthetic fluorohectorite nanocomposite. [source]


    Effect of clay with different cation exchange capacity on the morphology and properties of poly(methyl methacrylate)/clay nanocomposites

    POLYMER COMPOSITES, Issue 11 2009
    Tsung-Yen Tsai
    PMMA/clay nanocomposites were successfully prepared by in situ free-radical polymerization with the organic modified MMT-clay using methyl methacrylate monomer and benzoyl peroxide initiator. Two clays with different cation exchange capacity have been used to prepare and compare the several properties. The clays have been modified using Amphoterge K2 by ion exchange reaction to increase the compatibility between the clay and polymer matrices. The modified clays have been characterized by wide-angle X-ray diffraction pattern, Fourier transform infrared spectroscopy, and thermogravimetric analysis (TGA). The powdered X-ray diffraction and transmission electron microscopy techniques were employed to study the morphology of the PMMA/clay nanocomposites which indicate that the modified clays are dispersed in PMMA matrix to form both exfoliated and intercalated PMMA/modified clay nanocomposites. The thermomechanical properties were examined by TGA, differential scanning calorimetry, and dynamic mechanical analysis. Gas permeability analyzer shows the excellent gas barrier property of the nanocomposites, which is in good agreement with the morphology. The optical property was measured by UV,vis spectroscopy which shows that these materials have good optical clarity and UV resistance. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source]


    Morphology and properties of SAN-clay nanocomposites prepared principally by water-assisted extrusion

    POLYMER ENGINEERING & SCIENCE, Issue 1 2010
    Michaėl Mainil
    An efficient extrusion process involving the injection of water while processing was used to prepare poly (styrene- co -acrylonitrile) (SAN)/clay nanocomposites with a high degree of nanoclay delamination. The usefulness of water-assisted extrusion is highlighted here, in comparison with classical extrusion and roll mill processes. Cloisite® 30B (C30B), a montmorillonite clay organomodified with alkylammonium cations bearing 2-hydroxyethyl chains, and pristine montmorillonite were melt blended with SAN (25 wt% AN) in a semi-industrial scale extruder specially designed to allow water injection. XRD analysis, visual and TEM observations were used to evaluate the quality of clay dispersion. The relationship between the nanocomposite morphology and its mechanical and thermal properties was then investigated. The superiority of the SAN/C30B nanocomposite extruded with water has been evidenced by cone calorimetry tests and thermogravimetric measurements (TGA). These analyses showed a substantial improvement of the fire behavior and the thermal properties, while a 20% increase of the Young modulus was recorded. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source]


    Melt processing effects on the structure and mechanical properties of PA-6/clay nanocomposites

    POLYMER ENGINEERING & SCIENCE, Issue 8 2006
    Nitin K. Borse
    Polyamide-6 nanocomposites were prepared using two organoclays, Cloisite 30B and Cloisite 15A, and Cloisite Na+, which is unmodified sodium montmorillonite (Na-MMT) clay. Nanocomposites were prepared using two twin-screw extrusion systems: System B employing conventional mixing and residence time conditions, while System A was modified to achieve longer residence time and higher mixing efficiency. The work considers the effects of mixing conditions, residence time, and interactions between the polymer and clay surface on the structure and mechanical properties of polyamide-6 (PA-6)/clay nanocomposites. Furthermore, a comparison was made between experimental data and the predictions of composite models usually employed to predict mechanical properties of nanocomposites. The melt processing of Cloisite 30B in System A produced the highest degrees of exfoliation and the largest enhancement of mechanical properties. The aspect ratios of the filler particles in the nanocomposites were estimated from TEM micrographs and from composite models. Yield stress data were employed to calculate the values of parameter B in Pukanszky's equation, which incorporates the effects of the interfacial interaction, interfacial strength, and specific surface area of the filler particles. POLYM. ENG. SCI. 46:1094,1103, 2006. © 2006 Society of Plastics Engineers [source]


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

    POLYMER ENGINEERING & SCIENCE, Issue 9 2002
    Sangeeta Hambir
    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. [source]


    Synthesis and characterization of poly(butylene succinate)/epoxy group functionalized organoclay

    POLYMER INTERNATIONAL, Issue 9 2007
    Guang-Xin Chen
    Abstract Poly(butylene succinate) (PBS)/clay nanocomposites were prepared by condensation polymerization of 1,4-butanediol and succinic acid in the presence of an organoclay containing epoxy groups (TFC) and titanium(IV) butoxide as a catalyst. The intercalation and exfoliation of the clay layers in the resulting composite were examined using X-ray scattering and transmission electron microscopy. The role of the epoxy groups of TFC was investigated for the improvement of the morphology of the composites. The silicate layers in the composite were exfoliated to a greater extent as the epoxy content of TFC was increased from 0.245 to 0.359 mmol g,1, while only intercalated morphology was obtained when no epoxy was present. The improved morphologies were attributed to the enhanced interfacial interactions between PBS and TFC through a chemical reaction of the epoxy groups with the end groups of the PBS. The nonisothermal crystallization process of the composites as well as that of neat PBS is well represented by the Avrami equation as modified by Jeziorny [Jeziorny A, Polymer19:1142 (1978)]. The crystallization of the composite took place faster as the epoxy content of the clay increased, due to the more effective nucleation of the well-dispersed TFC layers. Copyright © 2007 Society of Chemical Industry [source]


    Twin-screw compounding of poly(methyl methacrylate)/clay nanocomposites: effects of compounding temperature and matrix molecular weight

    POLYMER INTERNATIONAL, Issue 8 2007
    Jr Hao Liaw
    Abstract Poly(methyl methacrylate) (PMMA)/organoclay nanocomposites prepared by melt-compounding using a co-rotating twin-screw extruder were intercalated nanocomposites. Commercially available PMMA resins of various molecular weights were used for comparison. The results showed an optimum compounding temperature for maximum intercalation with balanced shear and diffusion. Higher operating temperature reduced the shear mixing effect, and might have induced early degradation of the organoclay. Lower operating temperature, in contrast, reduced the mobility of the polymer molecules, which not only hampered the intercalation attempts, but also generated high torque in the extrusion. The mechanical behavior of the nanocomposites was studied. The tensile modulus, storage modulus and glass transition temperature of the nanocomposites increased with increasing clay content; however, an associated decrease in strength and strain at break was also observed. The notched impact strength also showed a slight decrease with clay content. Nanocomposites based on the lower molecular weight PMMA yielded more significant improvement in mechanical and thermal properties at the same clay content. Copyright © 2007 Society of Chemical Industry [source]


    The thermal conductivity of Nylon 6/clay nanocomposites

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008
    Hu Zhou
    Abstract Nylon 6/clay nanocomposites (NCNs) of different clay loadings are prepared by melt compounding. The effects of clay loading and dispersion on the thermal conductivity of NCNs are investigated using XRD, TEM, DSC, and POM. The results show that the thermal conductivity of the exfoliated NCNs decreases with an increase of clay content; but the thermal conductivity of the intercalated NCNs does not decrease, indeed, it increase markedly at high clay content. Such results observed in the exfoliated NCNs are opposite to the expectation of the classic Maxwell thermal conduction model. The further investigations indicate that such decrease observed in the exfoliated NCNs is due mainly to the exfoliation of clay layers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]


    Fiber breakage and dispersion in carbon-fiber-reinforced nylon 6/clay nanocomposites

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007
    Hu 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]


    High-Temperature Crystalline Phases in Nylon 6/Clay Nanocomposites

    MACROMOLECULAR RAPID COMMUNICATIONS, Issue 13 2005
    Xiaohui Liu
    Abstract Summary: Nylon 6/clay nanocomposites (N6CN) with different cooling histories were investigated by differential scanning calorimetry (DSC) and variable-temperature X-ray diffraction (XRD). Above the melting temperature, new endothermic peaks appeared in the DSC trace for N6CN. All the neat nylon 6 samples presented amorphous XRD patterns when heated up to the melting range. However, for N6CN samples, undefined crystalline structures remained in the substantially molten polymer matrix up to 300,°C. XRD patterns of a quenched nylon 6 sample annealed at 210,°C and N6CN samples annealed at 210, 230, and 300,°C, respectively. [source]


    Polymorphic behavior of nylon 6/saponite and nylon 6/montmorillonite nanocomposites

    POLYMER ENGINEERING & SCIENCE, Issue 6 2002
    Tzong-Ming Wu
    X-ray diffraction methods and DSC thermal analysis have been used to investigate the structural change of nylon 6/clay nanocomposites. Nylon 6/clay has prepared by the intercalation of ,-caprolactam and then exfoliaton of the layered saponite or montmorillonite by subsequent polymerization. Both X-ray diffraction data and DSC results indicate the presence of polymorphism in nylon 6 and in nylon 6/clay nanocomposites. This polymorphic behavior is dependent on the cooling rate of nylon 6/clay nanocomposites from melt and the content of saponite or montmorillonite in nylon 6/clay nanocomposites. The quenching from the melt induces the crystallization into the , crystalline form. The addition of clay increases the crystallization rate of the , crystalline form at lower saponite content and promotes the heterophase nucleation of , crystalline form at higher saponite or montmorillonite content. The effect of thermal treatment on the crystalline structure of nylon 6/clay nanocomposites in the range between Tg and Tm is also discussed. [source]


    Nylon 66/clay nanocomposite structure development in a twin screw extruder,

    POLYMER ENGINEERING & SCIENCE, Issue 4 2009
    Bin Lin
    Nylon 66/clay nanocomposites were prepared in a Berstorff ZE25A UTX Ultra-glide corotating twin screw extruder at 270°C. Two types of extruder configurations with different mixing sections were used. One comprised two kneading block sections in the screws (KB only) and the other had a combination of a multi-process-element (MPE) section and a kneading block section. Samples at eight different locations along the extruder screw were obtained and analyzed using scanning electron microscope and transmission electron microscope to examine the morphology development of clay inside nylon down the length of the extruder. It is found that the clay aggregates are quickly broken into smaller tactoids (micron size) and then even much smaller clay bundles (nanometer size) and single clay platelets in the first mixing section. The structure changes in the second mixing section are much less significant. X-ray diffraction (XRD) analysis of the nanocomposite products showed small, or disappearance of, characteristic XRD (001) peaks, which indicates partial exfoliation, or complete exfoliation, respectively, of clay inside nylon matrix. Differential scanning calorimetry nonisothermal study shows that the crystallization temperature of the nanocomposites has increased around 17°C when compared with neat nylon 66. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source]


    Preparation of Clay/PMMA Nanocomposites with Intercalated or Exfoliated Structure for Bone Cement Synthesis

    MACROMOLECULAR MATERIALS & ENGINEERING, Issue 6 2006
    Jyh-Horng Wang
    Abstract Summary: Clay/PMMA nanocomposites were prepared by melt blending of an organically modified MMT with PMMA under various process conditions. The MMT clay was initially cation exchanged with octadecylammonium to enhance its hydrophobicity and to expand the interlamellar space of the silicate plates. PMMA was then inserted into the inter-lamellar space of the modified clay by melt blending at an elevated temperature. The effects of blending temperature, blending time, and clay/PMMA compositions on the level of expansion and homogenization were investigated. Composites with intercalated and/or exfoliated clay structure were obtained depending upon the process conditions, as confirmed by XRD diffractometry. The thermal decomposition temperature (Td) and glass transition temperature (Tg) of the composites were determined, respectively, by TGA and DSC analyses. Marked improvements, up to 35,°C, of the thermal stability (Td) with respect to pure PMMA were achieved for many of the composite samples. The Tg of the composites, however, does not increase accordingly. Furthermore, a novel type of bone cement was synthesized by applying the clay/PMMA nanocomposites as a substitute for PMMA in a typical formulation. These bone cements demonstrated much higher impact strength and better cell compatibility than the surgical Simplex P cement. Therefore, the bone cements with clay/PMMA nanocomposites meet the requirement for the architectural design of orthopedic surgery. TEM images of an OA-clay/PMMA composite. [source]


    Clay-reinforced epoxy nanocomposites

    POLYMER INTERNATIONAL, Issue 9 2003
    D Ratna
    Abstract Epoxy/clay nanocomposites were prepared using a conventional diglycidyl ether of bisphenol A (DGEBA) epoxy, cured with diethyltoluene diamine (DETDA). The nanocomposites were characterized by dynamic mechanical analysis. A modest increase in glass transition temperature and significant increase in storage modulus were achieved as a result of incorporation of clay. The formation of nanocomposite was confirmed by wide-angle X-ray analysis. The higher impact strength of the nanocomposite compared the DGEBA matrix was explained in terms of with the morphology observed by SEM. © 2003 Society of Chemical Industry [source]


    Effect of EVA as compatibilizer on the mechanical properties, permeability characteristics, lamellae orientation, and long period of blown films of HDPE/clay nanocomposites

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
    Juliano Marini
    Abstract Two ethylene-vinyl acetate (EVA) resins with 19% (EVA19) and 28% (EVA28) of vinyl groups were used as compatibilizers for nanocomposites of high-density polyethylene (HDPE) and nanoclays. Two nanoclays were also used, one with a nonpolar surfactant (C15A) and another with a polar surfactant (C30B). The HDPE/EVA19/C15A formed an intercalated structure, while the HDPE/EVA28/C30B had surfactant loss. Blown films of these compositions were produced. A two-phase morphology made of HDPE and EVA/nanoclay particles was observed, which was responsible for the increase in water vapor and oxygen permeability rates of the films. The elastic modulus E along the transverse direction of the films was higher than along the machine direction due to preserved orientation given by the spiral die; the lamellae orientation was measured by small-angle X-rays diffraction. The highest E was observed in the HDPE/EVA19/C15A film due to stronger interactions. The long period of the HDPE lamellas was not affected by the presence of the EVA and nanoclay. A model was proposed to explain the improvement in elastic modulus due to the processing conditions and components' interactions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]


    Melt processing and characterization of multicomponent polymeric nanocomposites containing organoclay

    POLYMER COMPOSITES, Issue 3 2007
    M. 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]


    A short review on rubber/clay nanocomposites with emphasis on mechanical properties

    POLYMER ENGINEERING & SCIENCE, Issue 11 2007
    R. Sengupta
    The invention of Nylon-6/clay nanocomposites by the Toyota Research Group of Japan heralded a new chapter in the field of polymer composites. This article highlights the work done in the field of rubber/clay nanocomposites. The preparations of rubber/clay nanocomposites by solution blending, latex compounding, and melt intercalation are covered and a thorough discussion of the mechanical properties of the various rubber/clay nanocomposite systems is presented. Other properties such as barrier, dynamic mechanical behavior, and thermal properties are also discussed. Finally, the future trends in the rubber/clay nanocomposites are mentioned. POLYM. ENG. SCI., 47:1956,1974, 2007. © 2007 Society of Plastics Engineers [source]


    Melt processing effects on the structure and mechanical properties of PA-6/clay nanocomposites

    POLYMER ENGINEERING & SCIENCE, Issue 8 2006
    Nitin K. Borse
    Polyamide-6 nanocomposites were prepared using two organoclays, Cloisite 30B and Cloisite 15A, and Cloisite Na+, which is unmodified sodium montmorillonite (Na-MMT) clay. Nanocomposites were prepared using two twin-screw extrusion systems: System B employing conventional mixing and residence time conditions, while System A was modified to achieve longer residence time and higher mixing efficiency. The work considers the effects of mixing conditions, residence time, and interactions between the polymer and clay surface on the structure and mechanical properties of polyamide-6 (PA-6)/clay nanocomposites. Furthermore, a comparison was made between experimental data and the predictions of composite models usually employed to predict mechanical properties of nanocomposites. The melt processing of Cloisite 30B in System A produced the highest degrees of exfoliation and the largest enhancement of mechanical properties. The aspect ratios of the filler particles in the nanocomposites were estimated from TEM micrographs and from composite models. Yield stress data were employed to calculate the values of parameter B in Pukanszky's equation, which incorporates the effects of the interfacial interaction, interfacial strength, and specific surface area of the filler particles. POLYM. ENG. SCI. 46:1094,1103, 2006. © 2006 Society of Plastics Engineers [source]


    Effects of addition of functionalized SEBS on rheological, mechanical, and tribological properties of polyamide 6 nanocomposites

    POLYMER ENGINEERING & SCIENCE, Issue 1 2010
    Yosuke Nishitani
    The effects of the addition of styrene-ethylene/butylene-styrene copolymer (SEBS) with various functionalized groups on the rheological, mechanical, and tribological properties on polyamide 6 nanocomposite filled with layered silicate (PA6/Clay) were investigated. Four types of SEBS: unmodified SEBS (SEBS), maleic anhydride grafted SEBS (SEBS- g -MA), amine group grafted SEBS (SEBS- g -NH2), and carboxyl group grafted SEBS (SEBS- g -COOH) were added with PA6/Clay nanocomposite to prepare various polymer blends. These polymer blends were extruded by a twin screw extruder and injection molded. Dynamic viscoelastic properties of these blends in the molten state and their tensile, impact, and tribological properties were evaluated. The viscoelastic properties were found to increase with the addition of SEBS and were highly influenced by the types of functionalized groups contained. Influence of the addition of SEBS on the mechanical properties of these systems differed for each mechanical property. Although the tensile properties decreased with SEBS, Izod impact properties improved with the addition of various functionalized SEBS. These mechanical properties and viscoelastic properties correlated closely with the size of dispersed SEBS particles and interparticle distance. The tribological properties also improved with the addition of SEBS, and the influence of the amount added was higher than the type of SEBS used. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source]


    Preparation of Poly(, -caprolactone)/Clay Nanocomposites by Microwave-Assisted In Situ Ring-Opening Polymerization

    MACROMOLECULAR RAPID COMMUNICATIONS, Issue 10 2007
    Liqiong Liao
    Abstract PCL/clay nanocomposites were prepared by microwave-assisted in situ ROP of , -caprolactone in the presence of either unmodified clay (Cloisite® Na+) or clay modified by quaternary ammonium cations containing hydroxyl groups (Cloisite 30B). This PCL showed significantly improved monomer conversion and molecular weight compared with that produced by conventional heating. An intercalated structure was observed for the PCL/Cloisite Na+ nanocomposites, while a predominantly exfoliated structure was observed for the PCL/Cloisite 30B nanocomposites. Microwave irradiation proved to be an effective and efficient method for the preparation of PCL/clay nanocomposites. [source]


    Catalytic activity during the preparation of PE/clay nanocomposites by in situ polymerization with metallocene catalysts

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009
    Paula Zapata
    Abstract Catalytic activity during the formation of polyethylene (PE)/clay nanocomposites by in situ polymerization with metallocenes was studied. Ethylene polymerization was carried out with the homogeneous metallocene in the presence of the clay particles and using the clay-supported metallocene catalyst. It was found that the catalytic activity of the homogeneous metallocene does not decrease in the presence of the clay particles and only a slight decrease of activity occurs using the clay-supported catalyst. The modification of the clay with MAO cocatalyst as well as its intercalation with ODA surfactant were found to play an important role during the in situ formation of the PE/clay nanocomposite. ODA-intercalated clay apparently facilitates the activation and monomer insertion processes on zirconocene centers located in internal sites of the clay structure. Although metallocene supported on MAO-treated clay exhibited somewhat lower catalytic activity than that supported directly on the ODA-intercalated clay, both systems favored the production of PE nanocomposites containing highly exfoliated clay particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]


    Morphology and Properties of Polyethylene/Clay Nanocomposite Drawn Fibers

    MACROMOLECULAR MATERIALS & ENGINEERING, Issue 1 2008
    Francesco Paolo La Mantia
    Abstract The influence of an elongational flow on the morphology of PE/clay nanocomposite drawn fibers was studied. An increase of the elastic modulus and the tensile strength as well as a decrease of the elongation at break are observed with increasing draw ratio. The applied elongational gradient orients the polymer chains and the clay particles along the spinning direction. When the applied flow results in the formation and the orientation of exfoliated nanoparticles, a pronounced increase of the mechanical properties is observed. The dispersed clay particles can be broken and oriented by the extensional flow, which might indicate a flow-induced intercalated/exfoliated morphology transition. [source]


    Catalytic activity during the preparation of PE/clay nanocomposites by in situ polymerization with metallocene catalysts

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009
    Paula Zapata
    Abstract Catalytic activity during the formation of polyethylene (PE)/clay nanocomposites by in situ polymerization with metallocenes was studied. Ethylene polymerization was carried out with the homogeneous metallocene in the presence of the clay particles and using the clay-supported metallocene catalyst. It was found that the catalytic activity of the homogeneous metallocene does not decrease in the presence of the clay particles and only a slight decrease of activity occurs using the clay-supported catalyst. The modification of the clay with MAO cocatalyst as well as its intercalation with ODA surfactant were found to play an important role during the in situ formation of the PE/clay nanocomposite. ODA-intercalated clay apparently facilitates the activation and monomer insertion processes on zirconocene centers located in internal sites of the clay structure. Although metallocene supported on MAO-treated clay exhibited somewhat lower catalytic activity than that supported directly on the ODA-intercalated clay, both systems favored the production of PE nanocomposites containing highly exfoliated clay particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]