@article { ISI:000225953600006, title = {In situ polymerization of ethylene with bis(imino)pyridine iron(II) catalysts supported on clay: the synthesis and characterization of polyethylene-clay nanocomposites}, journal = {Journal of Polymer Science Part A-Polymer Chemistry}, volume = {43}, number = {2}, year = {2005}, month = {JAN}, pages = {304-318}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

Polyethylene-clay nanocomposites were synthesized by in situ polymerization with 2,6-bis[1-(2,6-diisopropylphenylimino)ethyl] pyridine iron(II) dichloride supported on a modified montmorillonite clay pretreated with methylaluminoxane (MAO). The catalysts and the obtained nanocomposites were examined with wide-angle X-ray scattering. The exfoliation of the clay was further established by transmission electron microscopy. Upon the treatment of the clay with MAO, there was an increase in the d-spacing of the clay galleries. No further increase in the d-spacing of the galleries was observed with the iron catalyst supported on the MAO-treated clay. The catalyst activity for ethylene polymerization was independent of the Al/Fe ratio. The exfoliation of the clay inside the polymer matrix depended on various parameters, such as the clay content, catalyst content, and Al/Fe ratio. The crystallinity percentage and crystallite size of the nanocomposites were affected by the degree of exfoliation of the clay. Moreover, when ethylene was polymerized with a mixture of the homogeneous iron(II) catalyst and clay, the degree of exfoliation was significantly lower than when the polymerization was performed with a preformed clay-supported catalyst. This observation suggested that in the supported catalyst, at least some of the active centers resided within the galleries of the clay. (C) 2004 Wiley Periodicals, Inc.

}, keywords = {clay, In situ polymerization, Nanocomposites, polyethylene (PE), TEM, WAXS}, issn = {0887-624X}, doi = {10.1002/pola.20502}, author = {Ray, S and Galgali, G and Lele, Arundhati C. and Sivaram, S} } @article { ISI:000239581200006, title = {Crystallisation in polymer nanocomposites}, journal = {Materials Science and Technology}, volume = {22}, number = {7}, year = {2006}, month = {JUL}, pages = {797-806}, publisher = {MANEY PUBLISHING}, type = {Article}, address = {HUDSON RD, LEEDS LS9 7DL, ENGLAND}, abstract = {

Polymer nanocomposites are of interest as they exhibit extraordinary properties compared with the base polymer. The second phase dispersed in the polymer matrix can be carbon nanotubes, semi-conducting inorganic nanoparticles or layer silicates such as clay. Crystallisation in these materials is also of great interest. Polymers exhibit structures at various scales (e.g. lamella, unit cell and spherulites) and the presence of a second phase has a profound effect on crystallisation. General trends observed include acceleration/retardation of crystallisation, changes in spherulite morphology and, in a few cases, changes in the crystal structure. All these observations relate to the presence of a micrometre scale second phase. However, when the dimensions of the second phase are close to the chain dimensions, the effects on crystallisation become particularly interesting. An attempt is made in the present review to address the effect of a nanoscale second phase on aspects such as isothermal and non-isothermal crystallisation, spherulite growth, phase transformation and polymorphism.

}, keywords = {clay, crystallisation, Nanocomposites, polymer matrix composites}, issn = {0267-0836}, doi = {10.1179/174328406X101300}, author = {Jog, Jyoti Prakash} } @article { ISI:000241203400011, title = {Nanocomposites of polypropylene impact copolymer and organoclays: role of compatibilizers}, journal = {Polymer International}, volume = {55}, number = {11}, year = {2006}, month = {NOV}, pages = {1270-1276}, publisher = {JOHN WILEY \& SONS LTD}, type = {Article}, address = {THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND}, abstract = {

Nanocomposites of polypropylene impact copolymer and organoclays were prepared using different compatibilizers (polypropylene-graft-(maleic anhydride) (PPMA), polyethylene-graft-(maleic anhydride) (PEMA) and their mixture) and varying percentages of clay (3 and 6\%) in an attempt to obtain balanced mechanical properties. The nanocomposites were prepared by melt compounding and test specimens were prepared by injection molding. Mechanical properties such as tensile, flexural and Izod impact strength are reported. The clay dispersion was investigated using wide-angle X-ray diffraction while the phase morphology was characterized using scanning electron microscopy. It is shown that the mechanical properties of the system with mixed PPMA and PEMA compatibilizers showed the best balance of mechanical properties among the nanocomposites explored. (C) 2006 Society of Chemical Industry.

}, keywords = {clay, compatibilizers, Nanocomposites, polypropylene}, issn = {0959-8103}, doi = {10.1002/pi.2077}, author = {Deenadayalan, E. and Vidhate, Shailesh and Lele, Ashish K.} } @article { ISI:000259755300059, title = {Effect of organic modifiers and silicate type on filler dispersion, thermal, and mechanical properties of ABS-Clay nanocomposites}, journal = {Journal of Applied Polymer Science}, volume = {110}, number = {4}, year = {2008}, month = {NOV}, pages = {2374-2383}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

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{\textquoteright}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{\textquoteright}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

}, keywords = {clay, filler, mechanical, structure characterization, styrene-butadiene}, issn = {0021-8995}, doi = {10.1002/app.28699}, author = {Tiwari, Rajkiran R. and Natarajan, Upendra} } @article { ISI:000259651700007, title = {Hydrated clay for catalyst removal in copper mediated atom transfer radical polymerization(a)}, journal = {Macromolecular Rapid Communications}, volume = {29}, number = {18}, year = {2008}, month = {SEP}, pages = {1538-1543}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

A simple method has been described to remove catalyst from the copper mediated atom transfer radical polymerization (ATRP) of benzyl methacrylate and methyl methacrylate in anisole at 25 degrees C using hydrated natural clay (sodium montmorillonite, Na-clay). The method consists of (1) addition of hydrated clay (CU(I/)clay approximate to 5 wt.-\%) either during or after the polymerization, (2) oxidation of catalyst complex by exposing the terminated reaction mixture in air, and (3) filtration to obtain catalyst free polymer solution. A strong coordination of CuBr-ligand complex onto hydrated clay (10 wt.-\%

}, keywords = {Atom transfer radical polymerization (ATRP), Catalysts, clay, selectivity, synthesis}, issn = {1022-1336}, doi = {10.1002/marc.200800240}, author = {Munirasu, Selvaraj and Deshpande, Ashwini and Baskaran, Durairaj} } @article { ISI:000261582300006, title = {Molecular dynamics of copolyester/clay nanocomposites as investigated by viscoelastic and dielectric analysis}, journal = {Journal of Polymer Science Part B-Polymer Physics}, volume = {46}, number = {23}, year = {2008}, month = {DEC}, pages = {2539-2555}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

We have investigated the molecular dynamics of poly(ethylene glycol-co-cycloxeane-1,4-dimethanol terephthalate) (PETG) nanocomposites based on a organically modified layered silicate. Intercalated namocomposites were prepared by melt compounding technique as evidenced from the X-ray diffraction and transmission electron microscopy studies. Two relaxation processes were observed in pure PETG as well as in the nanocomposites. The low-temperature beta-process was assigned to the local motions of C=O polar groups and the alpha-process was due to the glass-rubber transition or the segmental relaxations associated with the polymer chain backbone. Presence of layered silicates accelerated alpha-relaxation dynamics in the nanocomposites accompanied by a depression in T(g) which was attributed to the reduced intermolecular cooperativity between intercalated polymers chains. Additionally, a direct comparison between the viscoelastic and dielectric studies shows excellent agreement between the accelerated alpha dynamics of the nanocomposites. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2539-2555, 2008

}, keywords = {clay, Dielectric relaxation, Nanocomposites, polyesters}, issn = {0887-6266}, doi = {10.1002/polb.21603}, author = {Kalgaonkar, Rajendra A. and Jog, Jyoti Prakash} } @article { ISI:000261922400011, title = {Cell proliferation and controlled drug release studies of nanohybrids based on chitosan-g-lactic acid and montmorillonite}, journal = {Acta Biomaterialia}, volume = {5}, number = {1}, year = {2009}, month = {JAN}, pages = {93-100}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

The present paper reveals the potential uses of novel hybrids of chitosan-g-lactic acid and sodium montmorillonite (MMT) in controlled drug delivery and tissue engineering applications. The drug-loaded novel nanohybrid films and porous scaffolds have been prepared by solvent casting and freeze-drying of the grafted polymer solution, respectively. Sodium Ibuprofen was loaded into nanohybrids of chitosan-g-lactic acid/sodium montmorillonite (CS-g-LA/MMT). Grafting of lactic acid and the drug loading were characterized by Fourier transform infrared spectroscopy. Formation of intercalated nanocomposites was confirmed by X-ray diffraction. Mechanical properties measurements have shown improvement in modulus and strength with expense of elongation by MMT reinforcement. The nanohybrids were found to be stable regardless of pH of the medium. The cell proliferation profile also shows that prepared nanohybrids are biocompatible. MMT reinforcement was found to control the drug (Ibuprofen) release rate in phosphate buffer saline solution (pH 7.4). MMT clay is therefore a viable additive for formulating sustained drug delivery systems based on lactic acid grafted chitosan. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

}, keywords = {Chitosan, clay, Controlled release, drug delivery systems, Nanocomposites}, issn = {1742-7061}, doi = {10.1016/j.aetbio.2008.08.007}, author = {Depan, Dilip and Kumar, Annamalai Pratheep and Singh, Raj Pal} } @article { ISI:000266529600001, title = {Nanoscale particles for polymer degradation and stabilization-trends and future perspectives}, journal = {Progress in Polymer Science}, volume = {34}, number = {6}, year = {2009}, month = {JUN}, pages = {479-515}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The field of nanoscience and nanotechnology is extending the applications of physics, chemistry, biology, engineering and technology into previously unapproached infinitesimal length scales. The polymer-nanoparticles/nanocomposites have been the exponentially growing field of research for developing the materials in last few decades and have been mainly focusing on the structure-property relationships and their development. Since the polymer-nanocomposites have been the staple of modern polymer industry, their durability under various environmental conditions and degradability after their service life are also essential fields of research. Thus, this article is intended to review the status of worldwide research in this aspect. Among various nanoparticulates, clay minerals and carbon nanotubes are more often used in enhancing physical, mechanical and thermal properties of polymers. In very few systems, the nano particulates have been incorporated into polymer as {\textquoteleft}nano-additives{\textquoteright} for both purposes: degradation and stabilization of polymers. The degradation and durability of polymers is reviewed in the presence of nanoparticles/nanocomposites under different environmental conditions. Nanoparticle-induced biodegradation of polymers is also discussed. (c) 2009 Elsevier Ltd. All rights reserved.

}, keywords = {Carbon nanotubes, clay, Degradation and stabilization, Nanocomposites, Nanoparticles, Polymer}, issn = {0079-6700}, doi = {10.1016/j.progpolymsci.2009.01.002}, author = {Kumar, Annamalai Pratheep and Depan, Dilip and Tomer, Namrata Singh and Singh, Raj Pal} } @article { ISI:000264095500002, title = {Parametric dependence studies on cracking of clay}, journal = {Physica A-Statistical Mechanics and its Applications}, volume = {388}, number = {8}, year = {2009}, month = {APR}, pages = {1352-1358}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

We have studied the shrinkage-crack patterns formed in the process of drying of clay/water slurries employing simple laboratory experiments. Both isotropic and directional drying was studied. The objective has been to examine the correlation between the solvent, materials parameters and the crack patterns. Attempt is made to fit the observations to specific models. The dynamics of the pattern formation process and the geometric properties of the crack patterns are found to be in conformity with the hydrodynamic model by Lee and Routh [W.P. Lee, A.F. Routh, Langmuir 20 (2004) 9887]. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {clay, Cracks pattern, Hydrodynamic model}, issn = {0378-4371}, doi = {10.1016/j.physa.2008.12.039}, author = {Pasricha, Kanika and Wad, Uday and Pasricha, Renu and Ogale, Satishchandra} } @article { ISI:000324656500008, title = {Clay entrapped Cu(OH)(x) as an efficient heterogeneous catalyst for ipso-hydroxylation of arylboronic acids}, journal = {Applied Catalysis A-General}, volume = {466}, year = {2013}, month = {SEP}, pages = {60-67}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A remarkably active, selective and stable montmorilonite-KSF entrapped Cu(OH)(x) catalyst, has been prepared for the ipso-hydroxylation of arylboronic acids under ambient conditions without requirement of any ligand or base. This catalyst shows excellent reusability without leaching and any significant loss in catalytic activity. The catalyst was characterized using, XRD, SEM, TPR, IR, XPS and BET surface area measurement techniques. (C) 2013 Elsevier B.V. All rights reserved.

}, keywords = {clay, Copper, heterogeneous catalysis, Phenols, Water chemistry}, issn = {0926-860X}, doi = {10.1016/j.apcata.2013.06.051}, author = {Dar, Bashir Ahmad and Bhatti, Prince and Singh, A. P. and Lazar, Anish and Sharma, Parduman R. and Sharma, Meena and Singh, Baldev} } @article { ISI:000330822900026, title = {Clay encapsulated Cu(OH)(x) promoted homocoupling of arylboronic acids: an efficient and eco-friendly protocol}, journal = {Applied Catalysis A-General}, volume = {470}, year = {2014}, month = {JAN}, pages = {232-238}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Cu(OH)(x) has been encapsulated over montmorillonite-KSF by simple ologomeric deposition strategy. The resulting catalyst has been employed for selective homocoupling of arylboronic acids under ambient conditions without requirement of any ligand or base. This catalyst is easy to recover and shows excellent reusability without losing its activity. Techniques like XRD, SEM, TPR, IR, BET surface area measurement and XPS were used to characterize the catalyst. The present method promises for the simple and clean homocoupling of arylboronic acids. (C) 2013 Elsevier B.V. All rights reserved.

}, keywords = {Biaryls, clay, Copper, Heterogenous catalyst, Homocoupling}, issn = {0926-860X}, doi = {10.1016/j.apcata.2013.10.048}, author = {Dar, Bashir Ahmad and Singh, Snehil and Pandey, Nalini and Singh, A. P. and Sharma, Priti and Lazar, Anish and Sharma, Meena and Vishwakarma, Ram A. and Singh, Baldev} } @article { ISI:000359067400013, title = {Methane hydrate formation in a test sediment of sand and clay at various levels of water saturation}, journal = {Canadian Journal of Chemistry}, volume = {93}, number = {8, 1, SI}, year = {2015}, month = {AUG}, pages = {874-881}, publisher = {CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS}, address = {65 AURIGA DR, SUITE 203, OTTAWA, ON K2E 7W6, CANADA}, abstract = {

Kinetics of methane hydrate formation with different ratios of silica sand and clay and different water saturations were studied. At suitable temperature and methane gas pressure, water in the void spaces of silica sand packing and intercalated area of clay were converted into hydrate. It was observed that the rate of hydrate formation increases with higher void space in the packing, and addition of clay in test sediment decreases water to hydrate conversion as well as rate of hydrate formation. Maximum water to hydrate conversion of 60.0\% was achieved in pure silica sand bed at 75\% water saturation. Presence of fine clay particles is expected to reduce the void spaces and thus may hinder effective mass transfer of hydrate forming gases in the bed. However, it is also possible that the bentonite clay used in this work may actually inhibit hydrate growth. Additional experiments in stirred tank reactor were carried out to understand the inhibiting effect of bentonite clay for hydrate formation.

}, keywords = {clay, formation kinetics, methane hydrate, Silica sand, water saturation}, issn = {0008-4042}, doi = {10.1139/cjc-2014-0537}, author = {Kumar, Asheesh and Sakpal, Tushar and Roy, Sudip and Kumar, Rajnish} } @article {48759, title = {Polyethylene-grafted sheet-like silsesquioxane nanocomposites with unprecedented adhesion to polar substrates}, journal = {ACS Applied Polymer Materials}, volume = {5}, year = {2023}, month = {JUL}, pages = {5972-5983}, type = {Article}, abstract = {

Polyethylene is a highly apolar polymer with very pooradhesionto most substrates, necessitating the use of tie layers. Therefore,the synthesis of functional polyethylene is a long-standing challengein catalytic ethylene polymerization. Here, we report the preparationof a nanocomposite comprising polyethylene covalently grafted ontosheet-like silsesquioxanes, with unprecedented adhesion to metal andglass. A norbornene-grafted, layered Mg-silsesquioxane is treatedwith Grubbs second-generation catalyst (G-II), and the identity ofcovalently tethered G-II is unambiguously ascertained. Covalentlytethered G-II catalyzes the ring opening metathesis polymerizationof cyclooctene to poly(cyclooctene). The resulting poly(cyclooctene)is catalytically hydrogenated to yield polyethylene. This polyethylenenanocomposite exhibited a bonding strength of the order of 100 MPaon stainless steel and aluminum, 10-fold higher than reported forengineered polyethylene copolymers. The nanocomposite exhibits anincrease in the polar component of surface energy, yet remains compatibleand cocrystallizes with a polyethylene matrix.

}, keywords = {adhesion, clay, Nanocomposite, Polyethylene, silsesquioxane}, issn = {2637-6105}, doi = {10.1021/acsapm.3c00649}, author = {Sharma, Vivek and Paulbudhe, Uday and Bachhar, Nirmalya and Chikkali, Samir H. and Kumaraswamy, Guruswamy} }