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Author ORCID Identifier
Open Access Dissertation
Doctor of Philosophy (PhD)
Polymer Science and Engineering
Year Degree Awarded
Month Degree Awarded
E. Bryan Coughlin
Radical polymerization is one of most versatile and easily implemented chain-growth polymerization methods for obtaining polymers, copolymers and polymer composites. As a synthetic process with over seventy years of investigation, it has enabled the production of materials that enriched the daily lives of humankind. The polymerization mechanism involves the fundamental steps of initiation, propagation, and termination events. This radical-based synthetic route provides many advantages, such as the reaction conditions are usually not as demanding as ionic and coordination-insertion polymerizations regarding the tolerance of water, chemical functionalities and impurities. This polymerization technique can be applied to a wide variety of monomers.
The major challenge during the early development of controlled radical polymerization resulted from the presence of radical combination, atom transfer and abstraction reactions, which bring difficulties in understanding polymerization kinetics and achieving well-defined polymer structures. Thereby, industrial and academic effort has been focusing on developing techniques that offered the prospect of control over radical polymerization. The seeds were laid for the major growth of controlled radical polymerization techniques in the 1990s. These approaches allow for the facile production of polymer architectures with complexities, from simple chains with narrow dispersity to di-block, tri-block and multi-block copolymers.
In Chapters 2 and 4 of this dissertation, radical addition fragmentation chain transfer (RAFT) polymerization was utilized to investigated well-defined polymer structures, enabling subsequent structure-property relationship investigations of polyelectrolyte solutions and multi-block copolymer membranes. In Chapter 3, nitroxide mediated polymerization (NMP) was performed to prepare polyisoprene that was successfully chain extended with chloromethyl styrene. The resulting diblock copolymer was quaternized for ionomer preparation. The analysis of their bulk as well as surface morphology was investigated.
Cyclic ketene acetals (CKA) can be polymerized through concomitant radical rearrangement and ring-opening mechanisms, to yield ester-based scission points on the resultant polymer backbone. An aliphatic and an aromatic CKAs were investigated in Chapter 5 to develop a fundamental understanding of CKA radical-mediated polymerization and charge transfer as a main competitive reaction.
Chapter 6 concludes on the areas of research and development that I believe will lead to further progress in the future.
Du, Yifeng, "RADICAL POLYMERIZATION: CHEMISTRIES, APPLICATIONS, DEVELOPMENTS, AND PERSPECTIVES" (2021). Doctoral Dissertations. 2307.