Physical Sciences and Mathematics Commons^™

Broadband Dielectric Spectroscopy Studies Of Nafion, David Walter Rhoades

Dissertations

In light of available literature regarding Nafion® materials, it is apparent that an information gap exists between the current state of understanding of Nafion relaxations and the dielectric behavior of these materials. Although the currently available dielectric relaxation data is accurate it is very limited in its scope—specifically in-depth broadband analyses are not available. As a result, very little information is available regarding the dependence of the relaxation processes on frequency and temperature. This presents an important opportunity for the exploration of the dielectric broadband relaxation behavior of Nafion® materials. The primary intent of this research is to quantify the …

Raft Synthesis Of Water-Soluble, Stimuli-Responsive Ab Diblock Copolymers, Ran Wang

Dissertations

A series of water-soluble, stimuli-responsive AB diblock copolymers were synthesized via the reversible addition-fragmentation chain transfer (RAFT) polymerization technique employing 2-(2- carboxyethylsulfanylthiocarbonylsulfanyl)propionic acid (CTA26) as the RAFT mediating agent.

First, a series of diacid functional trithiocarbonate chain transfer agents (CTA's) were synthesized and examined for their effectiveness as mediating agents in controlling the polymerization of «-butyl acrylate (nBA). Overall, CTA26 demonstrated good control in the homopolymerization of nBA with respect to the molecular weight and the molecular weight distribution, as well as its ability to form block copolymers with high reinitiating efficiency, and thus was chosen as the CTA for …

Photopolymerization And Characterization Of Crosslinked Thiol-Ene Networks And Poss/Thiol-Ene Nanocomposites, Tolecia Sharonda Shaunee Clark

Dissertations

Interests in the area of thiol-ene photopolymerization are rapidly expanding due to the numerous advantages over the polymers produced by traditional solvent based polymerizations. Although current research of photoinitiated thiol-ene polymerization is diverse, numerous opportunities are available for investigating structure/property and structure/reactivity relationships and novel material applications. This research in this dissertation includes a fundamental study of the effect of monomelic thiol functionality on thiol-ene polymerization kinetics and formation of the thiol-ene network structure, and an investigation of the development of novel silicate based thiol-ene nanocomposites. The first fundamental study investigates the effect of thiol functionality on the kinetics and …

Investigations Of Poly[(Styrene-Co-P-Methylstyrene)-Risobutylene- R-(Styrene-Co-P-Methylstyrene)] And Poly[(Acrylic Acid)-5-Styrene-Jb-Is0butylene-5-Styrene-Jb-(Acrylic Acid)], James Grabill Kopchick

Dissertations

The pMe study was conducted to understand the morphological and physical property changes that occur as the ratio of pMe to styrene is increased, effectively increasing the aliphatic units. By the introduction of pMe, the interface region becomes more blended/compatible as the pMe migrates to the interface. These pMe groups are theorized in effect to create multiple ‘anchors’ to distribute the loads experienced at the interface more effectively creating a synergistic effect on the final properties of the copolymers. The primary goals of the pentablock study were the characterization of unique membranes as related to …

Investigation Of The Synthesis And Polymerization Behavior Of Vinyl Benzoate, Selim Mehmet Erhan

Dissertations

The goal of this study is to present a method that gives higher conversions and molecular weights for the polymerization of vinyl benzoate than obtained in previous investigations.

Polyvinyl benzoate has benzene rings attached to the backbone chain, therefore is hard and rigid. This is a characteristic which has a large application area. However previous studies in polymerizing vinyl benzoate with bulk and solution polymerizations reported low yields and troublesome crosslinking, which has limited its application. Emulsion polymerization method has the advantage of giving high polymerization rates together with high molecular weights, and therefore was chosen as the method for …