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Full-Text Articles in Engineering
Bottom-Up Morphological Control Of Biphasic Polymer Particles Via Heterogeneous Polymerization, Heather S.C. Hamilton
Bottom-Up Morphological Control Of Biphasic Polymer Particles Via Heterogeneous Polymerization, Heather S.C. Hamilton
Doctoral Dissertations
Heterogeneous polymerization techniques are industrially relevant, scalable methods to synthesize polymer colloids and they have emerged in recent decades as viable methods to produce biphasic and morphologically complex polymer particles. The overarching goal of this thesis is to understand how heterogeneous polymerization techniques can be modified and optimized to control particle morphology through the systematic study of process parameters. Chapter 1 introduces relevant nomenclature and provides a brief historical perspective on the development of heterogeneous polymerization. This chapter also reviews the state-of-the-art techniques used to prepare morphologically complex polymer particles, with an emphasis on the heterogeneous polymerization processes studied in …
Engineering Polymers Through Impact Modification And Superheated Liquid Processing, Gregory Connor Evans
Engineering Polymers Through Impact Modification And Superheated Liquid Processing, Gregory Connor Evans
Doctoral Dissertations
A new approach to toughen anionically polymerized polyamide 6 (aPA6) was applied using reaction induced phase separation (RIPS). This method solved issues with particle dispersion, mixture viscosity, and additive concentration common with conventional rubber toughening thereby making it an ideal candidate for fiber reinforced aPA6 reaction injection molding (RIM). Octamethylcyclotetrasiloxane (D4) was used as a functional additive that undergoes RIPS during aPA6 polymerization and polymerizes to polydimethylsiloxane (PDMS). Controlled phase separation, modulus retention, and increased crystallinity were achieved at low additive concentrations. Optimal properties were achieved with 2 wt% D4. Fracture energy was measured at high …
Ultra-Thin Polymer Films And Hierarchical Composites: Processing And Mechanical Properties, Yujie Liu
Ultra-Thin Polymer Films And Hierarchical Composites: Processing And Mechanical Properties, Yujie Liu
Doctoral Dissertations
Properties and fabrications of ultra-thin polymer films and hierarchical composites are of great interest in packaging, electronics, separations, and other manufacturing fields. However, due to the inherently fragile nature of ultra-thin polymer films, measuring their properties has proven difficult. Additionally, variables controlling thin polymer patterns (e.g. substrate wetting property) and composites (weight percent of particulates in matrix) formation have not been fundamentally well understood. Within this spectrum, fundamental understanding of formation mechanisms of these patterns and composites are needed. Additionally, a new characterization technique is required to be able to measure the mechanical properties of fabricated composites and thin films. …
Tailoring Nanoparticles And Polymers For Cooperative Interfacial And Surface Interactions, Irem Bolukbasi
Tailoring Nanoparticles And Polymers For Cooperative Interfacial And Surface Interactions, Irem Bolukbasi
Doctoral Dissertations
This thesis describes the synthesis of chemically functionalized nanoparticles and their behavior at interfaces and in conjunction with polymers. Solid-liquid, liquid-liquid, and air-liquid interfaces are useful platforms for studying nanoparticle assembly, especially when nanoparticles are functionalized to enable their segregation to the interface. At the liquid-liquid interface, double emulsions droplets, both oil-in-water-in-oil and water-in-oil-in-water, stabilized with nanoparticles were prepared. This involved gold nanoparticles stabilizing oil-in-water droplets, and CdSe quantum dots stabilizing water-in-oil droplets. These double emulsion droplets were by simply shaking to give polydisperse droplets, or in a well-defined fashion by microcapillary flow focusing. When nanoparticle-stabilized double emulsions were sized …
Synthesis And Interfacial Behavior Of Functional Amphiphilic Graft Copolymers Prepared By Ring-Opening Metathesis Polymerization, Kurt E. Breitenkamp
Synthesis And Interfacial Behavior Of Functional Amphiphilic Graft Copolymers Prepared By Ring-Opening Metathesis Polymerization, Kurt E. Breitenkamp
Open Access Dissertations
This thesis describes the synthesis and application of a new series of amphiphilic graft copolymers with a hydrophobic polyolefin backbone and pendent hydrophilic poly(ethylene glycol) (PEG) grafts. These copolymers are synthesized by ruthenium benzylidene-catalyzed ring-opening metathesis polymerization (ROMP) of PEG-functionalized cyclic olefin macromonomers to afford polycyclooctene- graft -PEG (PCOE- g -PEG) copolymers with a number of tunable features, such as PEG graft density and length, crystallinity, and amphiphilicity. Macromonomers of this type were prepared first by coupling chemistry using commercially available PEG monomethyl ether derivatives and a carboxylic acid-functionalized cycloctene. In a second approach, macromonomers possessing a variety of PEG …