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Controlling Silica Cluster Dispersion Through Thermoresponsive Binders

Bava, Luciana
http://rave.ohiolink.edu/etdc/view?acc_num=case1217562656

Abstract Details

2008, Doctor of Philosophy, Case Western Reserve University, Chemical Engineering.
The hydrodynamic dispersibility of fine particle agglomerates into polymeric media is affected by interparticle and particle-medium interaction forces. Binders are used to modify these interactions and ultimately, to enhance material properties and control processability. While traditional binders change the particle-particle and particle-matrix interactions to a degree that depends primarily on the chemical nature of the additive and its concentration within the agglomerate, responsive binders present an innovative alternative to control and improve the dispersion phenomenon: agglomerates incorporating responsive polymers allow the adjustment of particle-particle and particle-fluid interactions by manipulating an external processing parameter. In this work, we have used thermoresponsive binders, namely the linear and crosslinked form of poly(N-isopropyl acrylamide) (PNIPAM) to identify changes in the dispersion behavior of silica clusters driven by the experimental temperature. The linear form of PNIPAM shows a LCST (lower critical solution temperature) at around 32°C, whereas the crosslinked PNIPAM networks show a swelling/shrinking transition at about the same temperature. While in the case of the linear binder, dispersion is enhanced at temperatures below 32°C, the presence of the crosslinked binder changes dispersion behavior in an opposite way. These developments are attributed to modifications in the particle interfacial chemistry when linear PNIPAM is adsorbed onto the silica surface, and to the disruption of the agglomerate structure caused by the swelling/shrinking transition of the PNIPAM gel particles. A phenomenological model accounting for the temperature effect induced by the presence of PNIPAM hydrogels on agglomerate cohesivity and dispersion behavior has been developed. Predicted dispersion behavior at different temperatures shows good agreement with experimental data.
Donald L. Feke, PhD (Committee Chair)
Ica Manas-Zloczower, PhD (Committee Member)
Stuart J. Rowan, PhD (Committee Member)
J. Adin Mann, PhD (Committee Member)
111 p.
Chemical Engineering
dispersion; cluster cohesivity; responsive polymers; agglomerate

Recommended Citations

Citations

  • Bava, L. (2008). Controlling Silica Cluster Dispersion Through Thermoresponsive Binders [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1217562656

    APA Style (7th edition)

  • Bava, Luciana. Controlling Silica Cluster Dispersion Through Thermoresponsive Binders. 2008. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1217562656.

    MLA Style (8th edition)

  • Bava, Luciana. "Controlling Silica Cluster Dispersion Through Thermoresponsive Binders." Doctoral dissertation, Case Western Reserve University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1217562656

    Chicago Manual of Style (17th edition)

case1217562656
549
© 2008, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.