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Barrier properties of polymer clay nanocomposites   Publication : [S.l.] Nova Science Pub Inc 2010 . 271 p. , Polymer nanocomposites are organic-inorganic hybrids where the high aspect ratio inorganic filler can be delaminated in the organic matrix at the nanometer scale, thus leading to significant enhancement of composite properties at very low filler volume fractions. With the advancement of polymer nanocomposites technology, significant enhancements in mechanical and thermal properties of the composites could be achieved. However, other important properties like gas barrier properties, which form an absolutely necessary requirement for the use of materials in packaging and storage applications, were relatively neglected. By improving the barrier performance of the materials by incorporation of high aspect ratio nano platelets, one can expect to reduce the thickness of the commercial packaging laminates and other materials where thick material is required to be used to provide barrier to various gases. This can thus lead to significant amount of savings in the material costs and can make the polymer materials more light and also transparent as the nano scale dispersed filler would not scatter light. This book examines the factors affecting barrier properties enhancement in polar polymer matrices, which are different from case when non polar polymers are involved, thus indicating that the performance has to be quantised by case-by-case basis. The commonly used conventional models for prediction of permeation reduction are also less representative of the true microstructure of the nanocomposites. Thus the barrier performance of the polymer nanocomposite materials is also explored, separate from the more bulk based mechanical properties. 26 cm. Date : 2010 Disponibilité : Exemplaires disponibles: La bibliothèque des sciences de l'ingénieur (1),

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Polymer nanocomposites : advances in filler surface modification techniques   Publication : [S.l.] Nova Science Pub Inc 2009 . 216 p. , Polymer nanocomposites revolutionised the research in this field owing to the tremendous improvement in the composite properties at very low filler volume fraction. The surface modification of the filler, generally layered silicate montmorillonite clay, is required to compatibilise the organic and inorganic phases. The inorganic clay was modified conventionally with alkyl ammonium ions and the exfoliated nanocomposites with polar polymers could be formed where the clay could be dispersed at nanometer scale. During the initial phase of nanocomposite developments, only ammonium ions of fixed chain length were exchanged on the clay surface. However, this technology suffered when polyolefins and other non-polar polymers were used owing to the difficulties in dispersion of polar clay in the hydrophobic matrices. At best, only partially exfoliated composites could be formed by using these ammonium modified clays. To circumvent these limitations, two possible routes have been followed. By polarising the polymer matrix (e.g. by addition of compatibilisers or surfactants), one can achieve compatibilisation between the organic-inorganic phases. However, this technology leads to deterioration of nanocomposite properties even though better delamination is achieved. On the other hand, one can also focus on the more efficient modification of the filler surface so that the residual polarity after modification of the surface with conventional ammonium ions is also eliminated. A number of new clay surface modification techniques have been developed in the recent years which help in the generation of more exfoliated polymer nanocomposites. These techniques do not rely on the ion exchange of fixed chain length ammonium ions, but lead to generation/exchange of long and polydisperse polymer chains. These techniques include grafting of polymers to the clay surface, grafting of polymers from the clay surface, controlled living polymerisation from the clay surface, in situ generation of polyolefins from the clay surface and clay surface reactions etc. and form very robust technologies for the complete organophilisation of the clay surface. The generation of thick brushes around the clay surface owing to the better surface modification leads to better coverage of the electrostatic forces binding the clay platelets together and also leads to higher basal plane spacing between them. As a result, the modified platelets are more susceptible to exfoliation when compounded with the polymer matrices. 26 cm. Date : 2009 Disponibilité : Exemplaires disponibles: La bibliothèque des sciences de l'ingénieur (1),

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Nanocomposites, nanoparticles, and nanotubes / par Adregno, Michael A. Publication : Hauppauge, N.Y. : Nova Science Publishers, 2011 . 251 pages : 27 cm. Date : 2011 Disponibilité : Exemplaires disponibles: La bibliothèque des sciences de l'ingénieur (1),

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