Date of Award

2018

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

First Advisor

Brian Benicewicz

Abstract

Modification of surfaces with polymer brushes has become an important area of research for developing materials with a variety of advanced properties. Flat or continuous surfaces modified with polymer brushes can serve as surfaces where chemical reactions or separations take place, and discrete nanoparticles covered in a polymer brush can disperse within a miscible surrounding polymer, generating a composite which retains the processability of the polymer but becomes endowed with the properties of the filler as well. Presented herein are new synthetic approaches to modify both continuous surfaces as well as discrete particles with polymer brushes for complex applications. In the first chapter which details new work, the ability of foam monoliths grafted with a polymer brush to serve as a scaffold for plutonium separations is discussed. In this first part of a two-part story, a photoinitiated polymerization generates surface grafted chains of a functional polymer brush on a foam surface, and the resulting monoliths were tested for their plutonium capacity as well as separation efficiency compared to a commercial resin used for the same purpose. The light used to initiate the surface polymerization was found to have poor penetration into the center of the opaque monoliths which negatively affected the viii monolith’s capacity, but narrow elution profiles of the loaded plutonium hinted at the potential for macroporous foams to serve as very efficient scaffolds for separations. An extension of this work saw the development of an improved synthetic strategy with the aim of improving the plutonium capacity of the foam as well as devising a strategy to control the graft density and molecular weight of grafted polymer chains. The separation characteristics and recyclability of these materials was investigated and is discussed in detail. Focus then shifted to the development of well-defined polyethylene grafted silica nanoparticles. Polyethylene represents the largest class of commodity plastics used globally but is underexplored in the nanocomposites community due to the synthetic challenge of making well-defined polyethylene and attaching it to surfaces. A unique synthetic approach to prepare polyethylene grafted particles was devised, and the materials made using this procedure were thoroughly characterized. Finally, some conclusions about what was learned as well as some suggestions about how this work might proceed are offered in light of the work presented herein.

Rights

© 2018, Julia G. Pribyl

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