Synthesis and application of some novel functional polymers via controlled radical polymerization and click chemistry

Abstract

The objective of this thesis was to prepare thermoresponsive PEG-based homopolymers and copolymers by combination of cobalt-mediated catalytic chain-transfer polymerization (CCTP) and thiol-ene “click” chemistry and prepare well-defined glycopolymers via “living” polymerization and “click” chemistry. The effect of different catalysts for the nucleophilic mediated thiol-ene reaction was investigated using model compounds, both monomers and oligomers obtained by CCTP. Different catalysts, including pentylamine and hexylamine (primary amines), triethylamine (tertiary amine), and two different phosphines, dimethylphenylphosphine (DMPP) and tris(2-carboxyethyl) phosphine (TCEP), were investigated in the presence of different thiols. The optimum reaction conditions for nucleophile mediated thiol-ene click reactions were investigated. Thermoresponsive PEG-based homopolymers and copolymers of OEGMEMA obtained by CCT were modified using thiol-ene click chemistry with a variety of different functional thiol compounds to yield functional thermoresponsive polymers in high yield. The effect of different solvent systems for based catalyzed thiol-ene reaction was investigated in the presence of different functional thiols. The ATRP polymerization of TMS-PgMA and TIPS-PgMA and ROP polymerization of aliphatic polyester were investigated. A maleimide functional initiator was used in order to achieve post conjugation of nanoparticles for drug delivery. Moreover, the disulfide based bifunctional initiator was introduced into the midpoint of the polymer chain, which could break down to afford the corresponding polymer chain with thiol end group under the reducing condition. The thiol-terminated polymer was also post-functionalized via thiol-ene click chemistry. In addition, the aliphatic polycarbonate is a biocompatible and biodegradable polymer, which is widely used in medical and pharmaceutical applications. The subsequent introduction of sugar moiety to the reactive polymer chain via CuAAC click reaction and then the interactions between glycopolymers and lectins were investigated by Surface Plasmon Resonance (SPR) and Quartz Crystal Microbalance with Dissipation (QCM-D). The controlled SET-LRP polymerization of TMS-PgMA and SET-RAFT polymerization PgMA with the intact alkyne at ambient temperature were investigated. A maleimide functional initiator and CPDB, as the chain transfer agent have been employed. The introduction of maleimide moiety was to allow for post polymerization conjugation to peptides via reaction with cysteines. The subsequent introduction of sugar azides to click with the reactive polymer containing alkyne group and the glycopolymers through CuAAC was also investigated. The glycopolymer has been successfully prepared combining the SET-LRP/SET-RAFT and CuAAc click chemistry at ambient temperature