New Methodologies in Controlled Polymerizations of Main Chain Fluorinated Monomers and Cyclic Esters

Authors

Olumide Ibikunle AdeboluFollow

Date of Completion

5-3-2013

Embargo Period

5-3-2015

Keywords

Controlled radical polymerization, VDF, IDT, Hypervalent Iodides, Block Copolymers, Azides, Click Chemistry, Photochemistry

Major Advisor

Prof. Alex Asandei

Associate Advisor

Prof. Douglas Adamson

Associate Advisor

Prof. Rajeswari Kasi

Field of Study

Chemistry

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

This dissertation focuses on identification and development of new methodologies in complex polymer synthesis in relation to the living ring opening polymerization (LROP) of cyclic esters and controlled radical polymerization (CRP) of main chain fluorinated monomers.

The use of Cp₂ZrHCl was evaluated as a milder route to replace the toxic Sn(oct)₂ in LROP of ε-Caprolactone at 90 °C.

By contrast to typical high-temperature (100−250 °C) telo-/polymerizations of gaseous fluorinated monomers, carried out in high-pressure metal reactors, the visible light, Mn₂(CO)₁₀-/Bu₆Sn₂-photomediated initiation of vinylidene fluoride (bp = −83 °C) polymerization occurs readily from a variety of alkyl, semifluorinated, and perfluorinated halides at 40 °C, in low pressure glass tubes and in a variety of solvents, including water and alkyl carbonates. Perfluorinated alkyl iodide initiators also induce a controlled radical polymerization (CRP) via iodine degenerative transfer (IDT). While IDT proceeds with accumulation of the less reactive Pm-CF₂-CH₂-I vs the Pn-CH₂-CF₂-I chain ends, Mn₂(CO)₁₀/Bu₆Sn₂ enables their subsequent quantitative activation toward the synthesis of well-defined poly(vinylidene fluoride)block copolymers with a variety of other monomers.

Commercially available (CF₃COO)₂I^IIIPh, (CH₃COO)₂I^IIIPh and (CH₃COO)₃I^V(PhCOO) are introduced as the least expensive and most convenient CF₃/CF₃I and CH₃/CH₃I precursors for metal-free, photo(trifluoro)(iodo)methylations of alkenes, as illustrated (and the first example of DMPI photolysis) by the first examples of their use as photoinitiators in the polymerization of vinylidene fluoride (VDF), which by contrast to typical high temperature, high pressure metal reactor requirements, was accomplished under very mild conditions (40 °C), in glass tubes. The practicality of HVICs in VDF-CRP was demonstrated with both external (I(CF₂)₆I), and in situ generated (CF₃I) iodine chain transfer agents, via the first examples of I₂-VDF-CRP.

The first example of azide initiated and terminated VDF polymerization was demonstrated using cerium ammonium nitrate (CAN) and sodium azide (NaN₃). While typical free radical polymerization was obtained with azide radical alone, however, in the presence of external (I(CF₂)₆I) or in situ generated (CF₃I) chain transfers agents, VDF-CRP-IDT was obtained. Further click chemistry enabled the synthesis of block copolymer.

Recommended Citation

Adebolu, Olumide Ibikunle, "New Methodologies in Controlled Polymerizations of Main Chain Fluorinated Monomers and Cyclic Esters" (2013). Doctoral Dissertations. 89.
https://digitalcommons.lib.uconn.edu/dissertations/89