00719nas a2200145 4500008004100000022001400041245017300055210006900228260007900297300001300376490000800389100002300397700002500420856012800445 2006 eng d a0065-772700aPreparation and characterization of a series of new organically modified montmorillonite clays using X-ray diffraction, thermogravimetric analysis and FTIR spectroscopy0 aPreparation and characterization of a series of new organically  a1155 16th ST, NW, Washington, DC 20036 USAbAmerican Chemical SocietycMAR a211-COLL0 v2311 aNatarajan, Upendra1 aTiwari, Rajkiran, R. uhttps://library.ncl.res.in/content/preparation-and-characterization-series-new-organically-modified-montmorillonite-clays-002226nas a2200217 4500008004100000022001400041245014600055210006900201260006800270300001400338490000800352520138100360653002601741653001901767653001501786653001401801653002301815100002501838700002301863856012201886 2007 eng d a0021-899500aInfluence of organic modification on mechanical properties of melt processed intercalated poly(methyl methacrylate)-organoclay nanocomposites0 aInfluence of organic modification on mechanical properties of me a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcSEP a2433-24430 v1053 a

The influence of organic modifiers on intercalation extent, structure, thermal and mechanical properties of poly(methyl methacrylate) (PMMA)-clay nanocomposites were studied. Two different organic modifiers with varying hydrophobicity (single tallow versus ditallow) were investigated. The nanocomposites were prepared from melt processing method and characterized using wide angle X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry (DSC), and tensile tests. Mechanical properties such as tensile modulus (E), break stress (sigma(brk)), and 0% break strain (epsilon(brk)) were determined for nanocomposites at various clay loadings. Extent of PMMA intercalation is sufficient and in the range 9-15 angstrom depending on organoclay and filler loading. Overall thermal stability of nanocomposites increases by 16-30 degrees C. The enhancement in T-g of nanocomposite is merely by 2-4 degrees C. With increase in clay loading, tensile modulus increases linearly while % break strain decreases. Break stress is found to increase till 4 wt % and further decreases at higher clay loadings. The overall improvement in thermal and mechanical properties was higher for the organoclay containing organic modifier with lower hydrophobicity and single tallow amine chemical structure. (c) 2007 Wiley Periodicals, Inc.

10amechanical properties10aNanocomposites10aorganoclay10astructure10aThermal properties1 aTiwari, Rajkiran, R.1 aNatarajan, Upendra uhttps://library.ncl.res.in/content/influence-organic-modification-mechanical-properties-melt-processed-intercalated-002501nas a2200217 4500008004100000022001400041245013400055210006900189260006800258300001400326490000800340520167400348653000902022653001102031653001502042653003102057653002202088100002502110700002302135856012502158 2008 eng d a0021-899500aEffect of organic modifiers and silicate type on filler dispersion, thermal, and mechanical properties of ABS-Clay nanocomposites0 aEffect of organic modifiers and silicate type on filler dispersi a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcNOV a2374-23830 v1103 a

Acrylonitrile-butadiene-styrene (ABS)-clay composite and intercalated nanocomposites were prepared by melt processing, using Na-montmorillonite (MMT), several chemically different organically modified MMT (OMMT) and Na-laponite clays. The polymer-clay hybrids were characterized by WAXD, TEM, DSC, TGA, tensile, and impact tests. Intercalated nanocomposites are formed with organoclays, a composite is obtained with unmodified MMT, and the nanocomposite based on synthetic laponite is almost exfoliated. An unintercalated nanocomposite is formed by one of the organically modified clays, with similar overall stack dispersion as compared to the intercalated nanocomposites. T, of ABS is unaffected by incorporation of the silicate filler in its matrix upto 4 wt % loading for different aspect ratios and organic modifications. A significant improvement in the onset of thermal decomposition (40-44 degrees C at 4 wt % organoclay) is seen. The Young's modulus shows improvement, the elongation-at-break shows reduction, and the tensile strength shows improvement. Notched and unnotched impact strength of the intercalated MMT nanocomposites is lower as compared to that of ABS matrix. However, laponite and overexchanged organomontmorillonite clay lead to improvement in ductility. For the MMT clays, the Young's modulus (E) correlates with the intercalation change in organoclay interlayer separation (Delta d(001)) as influenced by the chemistry of the modifier. Although ABS-laponite composites are exfoliated, the intercalated OMMT-based nanocomposites show greater improvement in modulus. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110:2374-2383, 2008

10aclay10afiller10amechanical10astructure characterization10astyrene-butadiene1 aTiwari, Rajkiran, R.1 aNatarajan, Upendra uhttps://library.ncl.res.in/content/effect-organic-modifiers-and-silicate-type-filler-dispersion-thermal-and-mechanical-002294nas a2200241 4500008004100000022001400041245012300055210006900178260006800247300001400315490000800329520139100337653002601728653001901754653001501773653002601788653001601814653002301830100002501853700002301878700002301901856012801924 2008 eng d a0021-899500aNew poly(phenylene oxide)/polystyrene blend nanocomposites with clay: intercalation, thermal and mechanical properties0 aNew polyphenylene oxidepolystyrene blend nanocomposites with cla a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcMAY a1818-18280 v1083 a

We present the first study and results on the preparation and characterization of montmorillonite clay filter based polymer blend nanocomposites of the miscible poly(phenylene oxide)/polystyrene blend. Intercalated nanocomposites, prepared by a melt-processing method with 2-6 wt % commercially available organically modified sodium montmorillonite, have been characterized with wide-angle X-ray diffraction, transmission electron microscopy analysis, thermal analysis (thermogravimetric analysis and differential scanning calorimetry), and mechanical tensile tests. We show that nanocomposites can be successfully prepared in a batch mixer at temperatures much below the conditions conventionally used for this blend without organic degradation. Thermal stability is enhanced by nanoscale hybrid formation. The level of intercalation (change in the d-spacing) does not change with the clay loading. Better dispersion of clay in the blend matrix has been observed at a low level of clay content. The nanocomposites show improved tensile modulus (by 31%) in comparison to the blend, whereas the tensile strength (stress at break) and elongation decrease in the presence of the filler with an increase in the clay loading. The Halpin-Tsai model is able to predict the modulus of the nanocomposites in very good agreement with the experimental data. (c) 2008 Wiley Periodicals, Inc.

10amechanical properties10aNanocomposites10aorganoclay10apoly(phenylene oxide)10aPolystyrene10aThermal properties1 aTiwari, Rajkiran, R.1 aKhilar, Kartic, C.1 aNatarajan, Upendra uhttps://library.ncl.res.in/content/new-polyphenylene-oxidepolystyrene-blend-nanocomposites-clay-intercalation-thermal-and-001793nas a2200217 4500008004100000022001400041245006800055210006700123260007300190300001200263490000700275520104100282653002001323653001701343653002701360653001501387100002501402700002301427700002301450856010201473 2008 eng d a0169-131700aSynthesis and characterization of novel organo-montmorillonites0 aSynthesis and characterization of novel organomontmorillonites aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a203-2080 v383 a

Sodium Montmorillonite (NaMMT) has been modified via cation exchange reaction using three different organic cations. Basal spacings, interlamellar structure and thermal stability of these organo-montmorillonites (OMMT) clays have been characterized using wide angle X-ray diffraction (WARD) and thermogravimetric analysis (TGA) techniques. Increase in the basal spacing due to organic modification is in good agreement with simple theoretical calculations based on van der Waals volume of the cationic ammonium ions. TGA characterization and analysis show that the amount of organic modifier in the OMMT's is in good agreement with theoretically calculated stoichiometric content expected for almost complete exchange of Na+ ions by organic cations. The OMMT's shows stepwise decomposition corresponding to initial weight loss from residual water desorption, followed by decomposition of the organic surfactant and the dehydroxylation of structural water of the montmorillonite layers. (C) 2007 Elsevier B.V. All rights reserved.

10aMontmorillonite10aorgano-clays10aorgano-montmorillonite10asurfactant1 aTiwari, Rajkiran, R.1 aKhilar, Kartic, C.1 aNatarajan, Upendra uhttps://library.ncl.res.in/content/synthesis-and-characterization-novel-organo-montmorillonites-002747nas a2200217 4500008004100000022001400041245015700055210006900212260009800281300001200379490000700391520185900398653002002257653002602277653001902303653000902322653002302331100002502354700002302379856012702402 2008 eng d a0959-810300aThermal and mechanical properties of melt processed intercalated poly(methyl methacrylate)-organoclay nanocomposites over a wide range of filler loading0 aThermal and mechanical properties of melt processed intercalated aTHE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLANDbJOHN WILEY & SONS LTDcMAY a738-7430 v573 a

BACKGROUND: Poly(methyl methacrylate) (PMMA)-organoclay nanocomposites with octadecylammonium, ion-modified montmorillonite, prepared via melt processing, over a wide range of filler loading (2-16 wt%) were investigated in detail. These hybrids were characterized for their dispersion structure, and thermal and mechanical properties, such as tensile modulus (E). break stress (sigma(brk)), percent break strain (epsilon(brk)) and ductility(J), using wide-angle X-ray diffraction, transmission electron microscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile and impact tests. RESULTS: Intercalated nanocomposites were formed even in the presence of 16 wt% clay (high loading) in PMMA matrix. PMMA intercalated into the galleries of the organically modified clay, with a change in d-spacing in the range 11-16 angstrom. TGA results showed improved thermal stability of the nanocomposites. The glass transition temperature (T-g) of the nanocomposites, from DSC measurements, was 2-3 degrees C higher than that of PMMA. The ultimate tensile strength and impact strength decreased with increasing clay fraction. Tensile modulus for the nanocomposites increased by a significant amount (113%) at the highest level of clay fraction (16 wt%) studied. CONCLUSION: We show for the first time the formation of intercalated PMMA nanocomposites with alkylammonium-modified clays at high clay loadings (> 15wt%). Tensile modulus increases linearly with clay fraction, and the enhancement in modulus is significant. A linear correlation between tensile strength and strainat-break is shown. Thermal properties are not affected appreciably. Organoclay can be dispersed well even at high clay fractions to form nanocomposites with superior bulk properties of practical interest. (c) 2007 Society of Chemical Industry.

10aimpact strength10amechanical properties10aNanocomposites10aPMMA10aThermal properties1 aTiwari, Rajkiran, R.1 aNatarajan, Upendra uhttps://library.ncl.res.in/content/thermal-and-mechanical-properties-melt-processed-intercalated-polymethyl-methacrylate-002005nas a2200157 4500008004100000022001400041245017700055210006900232260007600301300001200377490000700389520127500396100002501671700002301696856012801719 2011 eng d a0032-388800aEffect of blend composition and organoclay loading on the nanocomposite structure and properties of miscible poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) blends0 aEffect of blend composition and organoclay loading on the nanoco aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcMAY a979-9910 v513 a

Organically-modified montmorillonite clay nanocomposites of poly(styrene-co-acrylonitrile) (SAN), poly(methyl methacrylate) (PMMA) and SAN/PMMA miscible blend are investigated. Structure characteristics at the nanoscale and microscale and thermal and tensile properties are studied as a function of polymer blend composition and filler loading fraction. Blend miscibility and T(g) are unaffected by up to 10% by wt. organoclay. Thermal degradation stability increases with SAN content and exhibits an optimum value of clay loading. Stiffness shows significant improvement. Tensile strength and elongation-at-break suffer as a result of nanocomposite formation. Modulus shows a maximum enhancement of 57% (5 +/- 0.06 GPa at 10 wt% filler, 20/80 SAN/PMMA) and varies linearly with clay fraction for all compositions of matrix phase. Predictions of Halpin-Tsai composite model are in excellent agreement with the experimental behavior over full range of polymer blend composition. Fundamental aspects of a polymer blend-clay nanocomposite are clarified, such as lack of additional synergy between clay platelets and matrix, and tensile ductility reduction, compared with polymer-clay system. POLYM. ENG. SCI., 51:979-991, 2011. (C) 2011 Society of Plastics Engineers

1 aTiwari, Rajkiran, R.1 aNatarajan, Upendra uhttps://library.ncl.res.in/content/effect-blend-composition-and-organoclay-loading-nanocomposite-structure-and-properties-002289nas a2200229 4500008004100000022001400041245013800055210006900193260008700262300001200349490000700361520139900368653001101767653001401778653001501792653002601807653001901833653003001852100002501882700002301907856012901930 2013 eng d a0892-705700aEffect of organic modification on the intercalation and the properties of poly(phenylene oxide)/polystyrene blend-clay nanocomposites0 aEffect of organic modification on the intercalation and the prop a1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLANDbSAGE PUBLICATIONS LTDcAPR a392-4150 v263 a

Nanocomposites prepared by the dispersion of unmodified and organically modified montmorillonite (MMT) clay into poly(2,6-dimethyl phenylene oxide)/polystyrene miscible blend in the range of 2-10 wt% clay were investigated by wide-angle x-ray diffraction, transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis and tensile mechanical tests. The systems based on unmodified sodium MMT (Na+MMT) as well as Cloisite 20A, Cloisite 30B and Cloisite 10A organically modified clays showed polymer intercalation. The glass transition temperature (T-g) value was not affected by the volume fraction of clay and chemical nature of the organoclay. The thermal degradation stability of nanocomposites is found to be only slightly better than that of the blend matrix. A percolation threshold of around 4 wt% organoclay loading is observed. An improvement of 35% relative to unfilled polymer blend matrix is observed for the modulus, for Cloisite 20A nanocomposite containing 2 wt% organoclay. The observed modulus improvement with significant retention of elongational tensile strength and tensile ductility in case of unmodified Na-MMT and Cloisite 30B nanocomposites appears promising. The modulus prediction using Halpin-Tsai model is found to be closer to the experimental data when MMT volume fraction rather than the organoclay volume fraction is used.

10afiller10ainterface10ainterphase10amechanical properties10aNanostructures10aPolymer-matrix composites1 aTiwari, Rajkiran, R.1 aNatarajan, Upendra uhttps://library.ncl.res.in/content/effect-organic-modification-intercalation-and-properties-polyphenylene-oxidepolystyrene-002147nas a2200229 4500008004100000022001400041245013000055210006900185260000800254300001400262490000700276520134400283653001101627653002601638653002001664653001901684653001501703653003001718100002501748700002301773856012101796 2020 eng d a0032-388800aCritical organic modifier aliphatic tail length for the formation of poly(methyl methacrylate)-montmorillonite nanocomposites0 aCritical organic modifier aliphatic tail length for the formatio cJUL a1604-16170 v603 a

In this article, we report the influence of organic modifier structure (alkyl chain length C8-C20, single vs ditallow) and thereby, the effect of hydrophobicity on the structure, thermal and mechanical properties of poly(methyl methacrylate) (PMMA)-clay hybrids. Melt processed PMMA-clay hybrids were characterized using wide-angle X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. The organoclays having an alkyl chain length of more than 12 CH2 groups resulted in the formation of nanocomposites. The glass transition temperature (T-g) of PMMA increased in the presence of clay. The mean-field lattice model was used to predict the free energy for nanocomposite formation, which showed a reasonable match with the experimental results and provided a general guideline for the proper selection of polymer and organoclay (ie, organic modifier) to obtain nanocomposite. Tensile modulus showed maximum improvement of 58% for the nanocomposites compared to 9% improvement for the composites. Tensile modulus increased with increases in the alkyl chain length of the organic modifier and clay loading. The level of improvement for the tensile properties of nanocomposites prepared from primary and secondary ammonium-modified clay is the same as that obtained with the commercial organoclays.

10ahybrid10amechanical properties10aMontmorillonite10aNanocomposites10aorganoclay10apoly(methyl methacrylate)1 aTiwari, Rajkiran, R.1 aNatarajan, Upendra uhttps://library.ncl.res.in/content/critical-organic-modifier-aliphatic-tail-length-formation-polymethyl-methacrylate