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Polymer and Organic Materials Commons™
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Full-Text Articles in Polymer and Organic Materials
Effects Of Polymer-Nanoparticle Interactions On The Dynamics Of Attractive Polyhedral Oligomeric Silsesquioxane Nanocomposites, Walter W. Young
Effects Of Polymer-Nanoparticle Interactions On The Dynamics Of Attractive Polyhedral Oligomeric Silsesquioxane Nanocomposites, Walter W. Young
Doctoral Dissertations
Polyhedral oligomeric silsesquioxane (POSS) had long been recognized as a critical building block for inorganic-organic hybrid materials with unique and desirable properties and performance. Through synthesis and characterization of polymer/POSS nanocomposites, direct insights into the significant effects of the polymer/POSS interactions on the resulting material properties are obtained. Random copolymers of a hydrogen-bond accepting monomer and a non-interacting monomer are synthesized and loaded with a model amine-functionalized hydrogen bond donating POSS molecule via solution casting, to create a material with well-controlled dynamical heterogeneity. The increase in the glass transition temperature (Tg) of these materials is found to strongly depend on …
Theory And Improved Methods For Probing The Cavitation To Fracture Transition, Christopher Barney
Theory And Improved Methods For Probing The Cavitation To Fracture Transition, Christopher Barney
Doctoral Dissertations
A material is considered soft when its bulk modulus is significantly greater than its shear modulus. Rubbery polymers are a class of soft materials where resistance to extension is mainly entropic in nature. Polymeric soft solids differ from liquids due to the presence of a percolated network of strong bonds that resist deformation and flow on a given time scale. The incompressible nature, entropically driven elasticity, and molecular scale network structure of soft polymeric solids combine to impart unique mechanical behavior that often results in complex material responses to simple loading situations. An important example of this is cavitation in …
Amorphous-Crystalline Brush Block Copolymers: Phase Behavior, Rheology And Composite Design, Gayathri Kopanati
Amorphous-Crystalline Brush Block Copolymers: Phase Behavior, Rheology And Composite Design, Gayathri Kopanati
Doctoral Dissertations
Bottlebrush block copolymers are polymers with chemically distinct polymer side chains grafted onto a common backbone. The unique architecture induced properties make these materials attractive for applications such as photonic materials, stimuli responsive actuators and drug delivery vehicles to name a few. This dissertation primarily investigates the phase transitions and rheological behavior of amorphous-crystalline bottlebrush brush block copolymers and their composites. The temperature induced phase behavior is investigated using time resolved synchrotron X-ray source. Irrespective of volume fraction and backbone length, the samples display strong segregation even at high temperatures (200 °C) and there is no accessible order-disorder transition in …
Fiber Formation From The Melting Of Free-Standing Polystyrene, Ultra-Thin Films: A Technique For The Investication Of Thin Film Dynamics, Confinement Effects And Fiber-Based Sensing, Jeremy M. Rathfon
Open Access Dissertations
Free-standing ultra-thin films and micro to nanoscale fibers offer a unique geometry in which to study the dynamics of thin film stability and polymer chain dynamics. By melting these films and investigating the subsequent processes of hole formation and growth, and fiber thinning and breakup, many interesting phenomena can be explored, including the nucleation of holes, shear-thinning during hole formation, finite-extensibility of capillary thinning viscoelastic fibers, and confinement effects on entanglement of polymer chains. Free-standing films in the melt are unstable and rupture due to instabilities. The mechanism of membrane failure and hole nucleation is modeled using an energy barrier …