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(a). (b). (c). (d). Shear Rate Dependent Structure of Polymer Stabilized TiO 2 Dispersions . A.I. Nakatani 1 , A. VanDyk 1 , L. Porcar 2,3 , J.G. Barker 3. DMR-0454672. 1 Rohm and Haas, 2 U. Maryland, 3 CHRNS.
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(a) (b) (c) (d) Shear Rate Dependent Structure of Polymer Stabilized TiO2 Dispersions A.I. Nakatani1, A. VanDyk1, L. Porcar2,3, J.G. Barker3 DMR-0454672 1Rohm and Haas, 2U. Maryland, 3CHRNS Little is known about the influence of shear on the structure and interactions within polymer-colloid systems. Light scattering is limited because of problems with opacity and turbidity. Instead ultra-high resolution SANS (“USANS”) is the technique of choice, given the typical size of colloidal particles (100’s of nm). A series of measurements using the USANS diffractometer has been performed on TiO2dispersions in polymer contrast-matched solvents to isolate the behavior of the oxide particles. The results provide important information with regard to differences in behavior, such as breakup or aggregation, on application and cessation of shear. Scattering intensities for TiO2 dispersions subjected to shear rates from 0.1 s-1 to 1000 s-1 and after cessation. The dispersions were stabilized with (a) high molecular weight (MW), and (b) low MW acrylate polymer salts, and with (c) high MW, and (d) low MW hydrophobic acrylate copolymer salts.