Functional degradable polymers via RAFT/MADIX mediated polymerization of cyclic ketene acetals and vinyl monomers

• Main Author: Hedir, Guillaume
• Published: University of Warwick 2016
• Subjects: 547; QD Chemistry
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694626

This thesis explores the synthesis of functional degradable polymers via the radical ringopening polymerization (rROP) of cyclic ketene acetal (CKA) monomers and their copolymerization with vinyl ester monomers using the reversible addition-fragmentation chain transfer (RAFT/MADIX) polymerization. Chapter 1 introduces the polymerization technique used in this thesis (namely RAFT polymerization) and gives a summary of the conventional and new approaches to synthesize poly(esters) for use as degradable materials, with a focus on the arising use of rROP of CKA monomers. In Chapter 2 the copolymerization of the CKA 2-methylene-1,3-dioxepane (MDO) and vinyl acetate (VAc) is investigated using RAFT/MADIX polymerization with a view towards the formation of degradable copolymers with controlled molecular weights and narrow dispersities. Chapter 3 discusses the use of the palladium vinyl exchange reaction to create a novel functional bromine derivative monomer of VAc, vinyl bromobutanoate (VBr). The homopolymerization of VBr and copolymerization with MDO using the RAFT/MADIX polymerization is further reported to produce homopolymers and degradable copolymers with functional pendent groups able to be further modified post-polymerization to introduce different properties to the polymer materials. In Chapter 4 further investigation into the RAFT/MADIX copolymerization of VAc and MDO, as well as its homopolymerization, is explored using a different chain transfer agent (CTA) in order to understand the cause of the lower degree of control observed for some of the copolymerizations in Chapter 2. Chapter 5 describes the formation of degradable hydrophilic copolymers showing tunable thermoresponsive properties via the copolymerization of MDO and novel oligo(ethyleneglycol) methyl ether vinyl acetate monomers. In Chapter 6 the copolymerization of MDO with vinyl ester monomers is presented using a macro-CTA of poly(N-vinylpyrrolidone) to create amphiphilic block copolymers of poly(NVP)-b-poly(MDO-co-vinyl esters) able to self-assemble in water to form degradable nanoparticles. Chapter 7 provides a summary of the work reported in Chapters 2-6 and potential perspectives for the methodology designed in this thesis.