Rheology of Advanced Polymer Systems under External Fields: Polymer Induced Turbulent Drag Reduction and Polymer/Carbon Nanotube Nanocomposites

Rheology of Advanced Polymer Systems under External Fields: Polymer Induced Turbulent Drag Reduction and Polymer/Carbon Nanotube Nanocomposites
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Part I Polymer Induced Turbulent Drag Reduction Turbulent drag reduction (DR) induced by various types of polymers in turbulent flow was investigated using a rotating disk apparatus (RDA). These polymers include water-soluble polymers such as polysaccharide xanthan gum (XG), or guar gum (GG) and also include oil-soluble polyisobutylene (PIB). The effects of various experimental conditions such as polymer molecular weight (MW), polymer concentration, rotational velocity of the disk, and temperature on the time dependence of drag reduction were investigated. The validity of the empirical exponential decay function, which has been used to represent the degradation phenomenon in polymer induced turbulent drag reduction in a pipe flow, has been investigated. Results show that the stretched-exponential model and Brostow model fit the experimental data best among the models. In addition, the DR efficiency of a polydisperse and high molecular weight calf thymus-DNA (CT-DNA) in turbulent flow was also examined. Its coil-to-globule transition by addition of spermidine (SPD) as condensing agent was studied under a turbulent flow, finding that DR efficiency of the CT-DNA was abruptly changed after the SPD addition. The resultant asymptote DR efficiency explains the origin of these changes, which can be conclusively verified via an electrophoresis experiment. Despite the different flow conditions, with or without a condensing agent, all CT-DNA molecules possessed the same half-cut dimension. Keywords: Drag reduction, Turbulent flow, Rotating disk apparatus, Polysaccharide, Xanthan gum, Guar gum, Copolymer, Water-soluble polymers, Polyisobutylene, Calf thymus-DNA, Spermidine, Mechanical degradation, Rheology, Temperature, Molecular weight. Part II Synthesis and Rheological Characterization of Polymer/Carbon Nanotube Nanocomposites Since discovered in 1990s, carbon nanotubes (CNT) have attracted great interests throughout the academic and industrial world for its extraordina
Part I Polymer Induced Turbulent Drag Reduction 1 Chapter 1 Introduction 3 Chapter 2 Turbulent Drag Reduction 5 2.1Background 5 2.2 Definition of Drag Reduction 9 2.3 Theoretical Review 10 2.3.1 Classical Approaches 10 2.3.2 Polymer Dynamics in Turbulent Flow 13 2.3.3 Recently-Proposed Mechanisms 17 2.4 Polymer Induced Turbulent Drag Reduction Technique 19 2.5 Effect of Various Parameters on Drag Reduction Effectiveness 22 2.5.1 Effect of Polymer Concentration 22 2.5.2 Molecular Weight and Polydispersity Effects 22 2.5.3 Effect of Solvent 24 2.5.4 Effect of Temperature 25 Chapter 3 Apparatus 27 3.1 Apparatus for Drag Reduction Measurement 27 3.2 High-Precision Rotating Disk Apparatus 29 3.2.1 Main System Frame 30 3.2.2 Motor and Detector 30 3.2.3 Computer Interfacing Unit 32 3.2.4 Data Acquisition and Calibration 33 Chapter 4 Materials 35 4.1 Water Soluble Polymer 35 4.1.1 Water Soluble Nature Polymer 35 Xanthan Gum 35 Guar Gum 36 4.1.2 Synthetic Water Soluble Polymer 37 4.2 Organic Solvent Soluble Polymer 37 4.3 DNA 38 Chapter 5 Experimental Section 39 5.1 Water soluble polymer 39 5.1.1 Water soluble nature polymer 39 Xanthan Gum 39 Guar Gum 39 5.1.2 Synthetic Water Soluble Polymer 39 5.2 Organic Solvent Soluble Polymer 40 5.3 DNA 40 Chapter 6 Results and Disscussion 41 6.1 Water soluble polymer 41 6.1.1 Water Soluble Nature Polymer 41 Xanthan Gum 41 Guar Gum 44 6.1.2 Synthetic Water Soluble Polymer 50 6.2 Organic Solvent Soluble Polymer 58 6.3 DNA 63 Chapter 7 Conclusions 69 7.1Water Soluble Polymer 69 7.1.1 Water Soluble Nature Polymer 69 Xanthan Gum 69 Guar Gum 69 7.1.2 Synthetic Water Soluble Polymer 69 7.2 Organic Solvent Soluble Polymer 70 7.3 DNA 70 References for Part I 71 Part II Synthesis and Rheological
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College of Engineering(공과대학) > Polymer Science and Engineering (고분자공학) > Theses(고분자공학 석박사 학위논문)
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