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Phosphaalkene monomers and their polymerization

University of British Columbia

Living polymerization is a useful technique that is used to synthesize macromolecules with controlled architectures and tailor-made properties. Although this technique is widely used for the polymerization of organic monomers, the living polymerization of inorganic monomers is exceedingly rare. The prospect of synthesizing new inorganic-organic hybrid macromolecules with tailor-made structures is quite attractive due to the chemical functionality imparted by the inorganic moiety. Our group has developed the living anionic polymerization of Mes-P=CPh₂ to give chemically functional homo- and block-copolymers with phosphine moieties in the polymer backbone. Thus far, copolymers with styrene and isoprene have been prepared. In Chapter 2, the first poly(methylenephophine)-block-poly(methylmethacrylate) (PMP-b-PMMA) block copolymers will be reported. PMP-b-PMMA's with a variety of chain lengths have been synthesized and fully characterized by NMR spectroscopy, gel permeation chromatography (GPC) and matrix-assisted laser desorption-mass spectrometry (MALDI-MS). To fully understand the process of polymerization, the activation energy (Ea) was determined for the secBuLi-initiated polymerization of Mes-P=CPh₂ in nonpolar solvent toluene with TMEDA coordinator (Ea = 16.7 ± 0.7 kcal·mol-¹). In Chapter 3, a simple route to “masked” phosphaalkenes bearing P-Ar (Ar = aryl) and C-H substituents will be explored. The design of monomers bearing substituents smaller than Mesityl at phosphorus and phenyl at carbon, e.g. Mes-P=CPh2, poses considerable synthetic challenge. The present results will provide evidence that a masked phosphaalkene compound has been prepared as a transient species using a masked approach. The research included in this thesis extends the variety of phosphaalkene-based block copolymers that can be prepared. It also offers new perspectives in synthesis masked phosphaalkene compounds.

Text

2019-04-30

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/65494

Chemistry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/