Date of Thesis

9-5-2014

Thesis Type

Masters Thesis (Bucknell Access Only)

Degree Type

Master of Science

First Advisor

Eric Tillman

Abstract

The unique properties and application of polymers to nearly all field of industries has continued to inspire advancements in polymer chemistry. Recently, specialized polymers containing unique architectures and functionality have shown promise in the fields of drug delivery and alternative energy. Controlled radical polymerization (CRP) reactions can be used with a variety of different vinyl monomers to produce low polydispersity samples that retain end group functionality and can undergo post polymerization reactions to create these unique architectures. In this research, dibrominated poly(methyl acrylate) (BrPMABr) was prepared using a well-studied CRP called atom transfer radical polymerization (ATRP). The reaction mixture was used directly in a post polymerization reaction termed radical trap-assisted atom transfer radical coupling (RTA-ATRC) reaction to achieve cyclic PMA by intramolecular coupling of the functional ends to 2-methyl-2-nitroso propane (MNP). When the polymerization-to-cyclization crossover was performed as a one pot-two step sequence simply by the addition of the radical trap MNP and increased amounts of ligand-catalyst, cyclic PMA could be formed in yields up to 65% by adjusting the total volume during the intramolecular RTA-ATRC, based on gel permeation chromatography (GPC) analysis. When the ATRP reaction mixture containing the BrPMABr precursor was added drop-wise into a redox active solution containing MNP, yields of cyclic polymer were increased up to 75%. Cyclic PMA products had G-Values of approximately 0.8 in comparison to linear PMA precursors which is in agreement with G-Values seen from previously reported cyclic polymers. The effect of the ligand was studied, with the highest amounts of cyclic product obtained in intramolecular RTA-ATRC reactions using tris[2-(dimethylamino)ethyl]amine (Me6TREN) as the ligand. In analogous intramolecular ATRC trials lacking the radical trap, cyclization was not successful and instead chain extension by continuation of ATRP was observed. Cyclic diblock copolymers were also prepared by RTA-ATRC, using telechelic PMA-b-PSt-b-PMA precursors prepared by sequential ATRP reactions.

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