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Rheology of polymeric suspensions: polymer nanocomposites and waterborne coatings

Xu, Jianhua
http://rave.ohiolink.edu/etdc/view?acc_num=osu1127317214

Abstract Details

2005, Doctor of Philosophy, Ohio State University, Chemical Engineering.
In this work, the rheology of two types of polymeric suspensions, namely waterborne coatings and polymer/nanoclay and polymer carbon nanofibers (CNF) is studied. The steady shear viscosity as a function of shear rate of a metallic automotive basecoat is measured and the data is fitted to several constitutive models. The pressure drop of the paint flow in a straight circular pipe is measured in a pilot plant, and it is compared with the simulations using the constitutive models. It is found that Sisko model works very well for a wide range of flow rates. At the same time, the paint shows abnormal temperature effects on the rheology in the range of 10-45C, where the steady shear viscosity decreases and then increases with temperature. In the study of the rheology of CNF suspensions with a Newtonian fluid as solvent, it is found that the dispersion of the CNFs determines the suspension rheology. Steady shear viscosities of untreated sonicated suspensions are higher than that of better dispersed treated sonicated suspensions, due to the existence of large clumps and strong inter-particle interactions. Morphology investigations show that the acid treatment of the treated CNFs disintegrates the agglomerates exists in the as-received CNFs and therefore improves dispersion. However, the treatment also weakens the CNFs, as the subsequent sonication breaks most of them. Extensive shear and extensional rheological studies have been conducted on the polystyrene/CNF composites made by melt blending (MB) and solvent casting (SC) methods. The results show that the elastic and viscous moduli (G' and G") of the composites are greatly improved with higher CNF concentrations. Higher CNFs in the SC composites have more impact on the increase. Transient behavior, including transient shear viscosities and normal forces, can be related to the evolution of the CNF orientation and structure. Orientation of the CNFs induced by shear flow is measured, both as a function of the shear strain and of the shear rate. Our models show that the rheology of the composites can be captured and the orientation of the CNFs can be predicted and coupled with the rheology.
Kurt Koelling (Advisor)
Agriculture, Animal Pathology
Rheology; nanocomposites; coating; non-Newtonian

Recommended Citations

Citations

  • Xu, J. (2005). Rheology of polymeric suspensions: polymer nanocomposites and waterborne coatings [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1127317214

    APA Style (7th edition)

  • Xu, Jianhua. Rheology of polymeric suspensions: polymer nanocomposites and waterborne coatings. 2005. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1127317214.

    MLA Style (8th edition)

  • Xu, Jianhua. "Rheology of polymeric suspensions: polymer nanocomposites and waterborne coatings." Doctoral dissertation, Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1127317214

    Chicago Manual of Style (17th edition)

osu1127317214
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© 2005, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.