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Living anionic polymerization of phospaalkenes : controlled homopolymers and block copolymers with phosphorus atoms in the polymer main chain Noonan, Kevin Joseph Taaffe

Abstract

In this thesis, the living anionic polymerization of the phosphaalkene MesPCPh₂ is reported. The polymer backbone consists of alternating phosphorus and carbon atoms. Several experiments have been conducted to illustrate the living nature of P=C bond polymerization including: controlling the polymer chain length by varying the concentration of initiator, determining that molecular weight increases linearly with conversion and showing that the polymerization follows pseudo first order kinetics. Investigations into the mechanism of the n-butyllithium initiated MesP=CPh₂ polymerization allowed for the experimental determination of the activation energy of propagation for the growing polymer chain, Ea = 14.0 ± 0.9 kcal mol⁻¹. Several new block copolymer species have been prepared by sequential anionic polymerization including polystyrene-block-poly(methylenephosphine) and polyisoprene-block poly(methylenephosphine). The polyisoprene-block-poly(methylenephosphine) was coordinated to AuCI and dissolved in n-heptane to prepare micellar Au(l) spherical and wormlike nanostructures visible by transmission electron microscopy. Further evidence for the chemical functionality of the poly(methylenephosphine) species is reported in this thesis. Poly(methylenephosphine) was treated with several main group electrophiles to form a polymeric BH₃ coordination complex and a partially methylated phosphonium ionomer. Finally, several P=C compounds bearing functional groups (i.e,C₁₀ H₁₀ Fe, 4-Cl-C₆H₄, 4- NEt₂-C₆H₄)on the carbon substituent have been synthesized. Several of these systems have been investigated as monomers for the anionic polymerization P=C bonds. Not all of the monomers polymerize by anionic methods and studies to better understand this behavior are underway.

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