Southern Clay Products

Fifth Street, TX, United States

Southern Clay Products

Fifth Street, TX, United States

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Tiwari R.R.,University of Texas at Austin | Hunter D.L.,Southern Clay Products | Paul D.R.,University of Texas at Austin
Journal of Polymer Science, Part B: Polymer Physics | Year: 2013

Coefficients of linear thermal expansion (CTE) for poly(propylene)/ poly(propylene)-grafted-maleic anhydride/montmorillonite ethylene-co-octene elastomer (PP/PP-g-MA/MMT/EOR) blend nanocomposites were determined as a function of MMT content and various PP-g-MA/organoclay masterbatch ratios. The nanocomposites were prepared in a twin-screw extruder at a fixed 30 wt % elastomer, 0-7 wt % MMT content, and various PP-g-MA/organoclay ratio of 0, 0.5, 1.0, and 1.5. The organoclay dispersion facilitated by the maleated PP helps to reduce the size of the dispersed phase elastomer particles in the PP matrix. The elastomer particle size decreased significantly as the PP-g-MA/organoclay ratio and MMT content increased; the elastomer particles viewed // to flow direction (FD) are smaller and less deformed compared to those viewed // to transverse direction (TD). The elastomer particle shape based on the view along the three orthogonal directions of the injection molded sample is similar to a prolate ellipsoid. The CTE decreased significantly in the FD and TD, whereas a slight increase is observed in the normal direction in the presence of MMT and PP-g-MA. The Chow model based on a two population approach showed better fit to experimental CTE when the effect of MMT and elastomer are considered individually. © 2013 Wiley Periodicals, Inc.


Spencer M.W.,University of Texas at Austin | Hunter D.L.,Southern Clay Products | Knesek B.W.,Southern Clay Products | Paul D.R.,University of Texas at Austin
Polymer | Year: 2011

A silanized organoclay (s-M2(HT)2) was prepared by reaction of trimethoxyphenyl silane with an organoclay with a M 2(HT)2 surfactant structure. Nanocomposites were formed from polypropylene (PP) and a blend of PP and maleic anhydride-grafted polypropylene (PP-g-MA) and the M2(HT)2 and s-M 2(HT)2 organoclays by melt processing to explore the extent of exfoliation and the mechanical properties. Wide angle X-ray scattering (WAXS) and transmission electron microscopy (TEM) coupled with detailed particle analysis were used to determine the effect of the organoclay used and the PP-g-MA compatibilizer on exfoliation and mechanical, rheological, and thermal expansion properties. The PP/s-M2(HT)2 nanocomposites have higher particle densities than the PP/M2(HT) 2 nanocomposites though the aspect ratio remains the same. Platelet dispersion is significantly improved by using PP-g-MA compatibilizer for both organoclays. The rheological properties and the relative modulus improve for the PP/s-M2(HT)2 nanocomposites but not to the same degree as either organoclay in a PP-g-MA compatibilized matrix. The thermal expansion properties, however, are not improved by using the s-M2(HT) 2 organoclay. The s-M2(HT)2 organoclay is less prone to agglomeration during extrusion than the M2(HT)2 organoclay. © 2011 Elsevier Ltd. All rights reserved.


Tiwari R.R.,University of Texas at Austin | Hunter D.L.,Southern Clay Products | Paul D.R.,University of Texas at Austin
Journal of Polymer Science, Part B: Polymer Physics | Year: 2012

PP/PP-g-MA/MMT/EOR blend nanocomposites were prepared in a twin-screw extruder at fixed 30 wt % elastomer and 0 to 7 wt % MMT content. Elastomer particle size and shape in the presence of MMT were evaluated at various PP-g-MA/organoclay masterbatch ratios of 0, 0.5, 1.0, and 1.5. The organoclay dispersion facilitated by maleated polypropylene serves to reduce the size of the elastomer dispersed phase particles and facilitates toughening of these blend nanocomposites. The rheological data analysis using modified Carreau-Yasuda model showed maximum yield stress in extruder-made nanocomposites compared with nanocomposites of reactor-made TPO. Increasing either MMT content or the PP-g-MA/organoclay ratio can drive the elastomer particle size below the critical particle size below which toughness is dramatically increased. The ductile-brittle transition shift toward lower MMT content as the PP-g-MA/organoclay ratio is increased. The D-B transition temperature also decreased with increased MMT content and masterbatch ratio. Elastomer particle sizes below ∼1.0 μm did not lead to further decrease in the D-B transition temperature. The tensile modulus, yield strength, and elongation at yield improved with increasing MMT content and masterbatch ratio while elongation at break was reduced. The modified Mori-Tanaka model showed better fit to experimental modulus when the effect of MMT and elastomer are considered individually. Overall, extruder-made nanocomposites showed balanced properties of PP/PP-g-MA/MMT/EOR blend nanocomposites compared with nanocomposites of reactor-made TPO. Copyright © 2012 Wiley Periodicals, Inc.


Yoo Y.,University of Texas at Austin | Cui L.,University of Texas at Austin | Yoon P.J.,Southern Clay Products | Paul D.R.,University of Texas at Austin
Macromolecules | Year: 2010

The effects of addition of an organoclay on the morphology and the mechanical properties of blends of an amorphous polyamide (a-PA) and an elastomer (with and without grafted maleic anhydride) prepared via melt processing are reported. Transmission electron microscopy (TEM) and wide-angle X-ray scattering (WAXS) were employed to obtain a detailed quantitative analyses of the morphology of the elastomer particles for these nanocomposites containing 80 wt % a-PA and 20 wt % elastomer. Stress-strain diagrams and impact strength were measured as a function of organoclay content for blends containing malea ted and unmaleated elastomer. It is clear that the addition of organoclay to blends can be an effective way for reducing elastomer particle size and enhancing stiffness when the elastomer is not maleated; however, for this system, toughness is not improved in spite of these morphological changes. Blends based on the maleated elastomer give a more beneficial balance of toughness versus stiffness. © 2009 American Chemical Society.

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