The Aspect Ratio and Gas Permeation in Polymer-Layered Silicate Nanocomposites

2004 ◽  
Vol 25 (12) ◽  
pp. 1145-1149 ◽  
Author(s):  
Maged A. Osman ◽  
Vikas Mittal ◽  
Hans Rudolf Lusti
Keyword(s):  
Aspect Ratio ◽  
Layered Silicate ◽  
Gas Permeation ◽  
Silicate Nanocomposites

Epoxy-Layered Silicate Nanocomposites and Their Gas Permeation Properties

2004 ◽  
Vol 37 (19) ◽  
pp. 7250-7257 ◽  
Author(s):  
Maged A. Osman ◽  
Vikas Mittal ◽  
Massimo Morbidelli ◽  
Ulrich W. Suter
Keyword(s):  
Layered Silicate ◽  
Gas Permeation ◽  
Silicate Nanocomposites ◽  
Permeation Properties

scholarly journals Modeling of Tensile Modulus of Polyolefin-Layered Silicate Nanocomposites: Modified Halpin Tsai Models

2012 ◽  
Vol 21 (5) ◽  
pp. 096369351202100
Author(s):  
Vikas Mittal
Keyword(s):  
Aspect Ratio ◽  
Tensile Modulus ◽  
Layered Silicate ◽  
Adhesion Forces ◽  
Element Analysis ◽  
Tem Analysis ◽  
Simple Modification ◽  
Silicate Nanocomposites ◽  
Average Aspect Ratio ◽  
Modulus Reduction

The modified forms of Halpin Tsai model for the prediction of tensile modulus of polyolefin-layered silicate nanocomposites are discussed. The assumptions used in the conventional model like perfect alignment of the particulate filler, uniform shape and size of the filler particles as well as interfacial adhesion between the polymer and filler surface do not hold true in the case of polymer nanocomposites especially using polyolefinic matrices. The modulus reduction factors suggested for polar nanocomposites are also dependent on the polymer nature as well as filler morphology in the composite, thus, are not applicable directly to the polyolefin composites. A master curve could be generated for polyolefin nanocomposites which provided more accurate modulus reduction factor value based on the average aspect ratio of the filler. Incorporation of the effects of incomplete exfoliation as well as filler misalignment though improved the prediction capabilities of the model, however, it still did not match the predictions generated from finite element analysis or TEM analysis. The effect of absence of adhesion forces at the interface was incorporated by suggesting simple modification to the modified Halpin Tsai model equation. Master curves could be generated which predicted the relative tensile modulus of the composites accurately if the value of average aspect ratio was known.

Dispersion of Layered Organosilicates in Isobutylene-Based Elastomers

2006 ◽  
Vol 79 (2) ◽  
pp. 281-306 ◽  
Author(s):  
Andy H. Tsou ◽  
Matthew B. Measmer
Keyword(s):  
Aspect Ratio ◽  
Carbon Black ◽  
Layered Silicate ◽  
Tertiary Amines ◽  
Aspect Ratios ◽  
Silicate Nanocomposites ◽  
Dispersion State ◽  
Planar Orientation ◽  
Internal Mixer ◽  
Better Than

Abstract Dispersion morphologies of polymer-layered silicate nanocomposites based on either brominated poly(isobutylene-co-para-methylstyrene), BIMSM, or brominated poly(isobutylene-co-isoprene), BIIR, and an organosilicate, dimethylditallow ammonium-exchanged montmorillonite, Cloisite™ 6A, with and without N660 carbon black fillers were examined using SAXS, WAXS, AFM, and TEM. These compounds were prepared using an internal mixer and cured for property measurements. Due to the observed partial orientation of organosilicates and their possible heterogeneous intercalation, degrees of exfoliation and dispersion of organosilicates in BIMSM and BIIR were unable to be characterized and quantified simply by TEM, AFM, or SAXS alone. Instead, using the projected aspect ratio of organosilicates in BIMSM or BIIR, extracted from Gusev-Lusti equation based on measured permeability ratios, was found to provide a relative measure of their dispersion state. Since better dispersion, higher planar orientation, and/or increasing extent of exfoliation lead to higher aspect ratio, this calculated aspect ratio was used as a measure of organosilicate dispersion in BIMSM and BIIR compounds. According to experimentally extracted projected aspect ratios, it was found that BIMSM disperses organosilicates better than BIIR and that carbon black filler does not affect the organosilicate dispersion in BIMSM. Addition of tertiary amines in BIMSM enhances the dispersion of organosilicates, possibly through favorable interactions between organosilicates and quaternary ammonium functionalized BIMSM, resulting in further reduction in permeability.

Thermally-cured and e-beam-cured epoxy layered-Silicate nanocomposites

2003 ◽  
Vol 49 (6) ◽  
pp. 473-480 ◽  
Author(s):  
Chenggang Chen ◽  
David Curliss
Keyword(s):  
Layered Silicate ◽  
Silicate Nanocomposites
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