Application of controlled/'living' radical polymerisation techniques in the preparation of polymer hybrid materials

摘要

Polymer composites often display superior properties than the individual components. The current strategies employed suffer significant drawbacks including the formation of heterogeneous materials resulting from laborious chemical modifications. In this thesis, we report the preparation of novel polymeric hybrid materials based on cellulose, a naturally occurring polymer via physical blending. We demonstrate through the incorporation of a variety of synthetic polymers prepared via reversible addition–fragmentation chain transfer (RAFT) polymerisation that it is possible to incorporate functional polymers with cellulose using cooperative hydrogen bonding rather than the covalent methods traditionally used. We also show that polymers that are typically incompatible with natural polymers can be incorporated successfully by the addition of another block bearing polar moieties. The simplicity of this approach combined with the versatility of modern polymerisation techniques will prove a more cost-effective route to prepare biopolymer-based materials with improved functionality. We also report the preparation of inorganic-organic core–shell hybrid materials from a silica nanoparticle template using surface-initiated single-electron transfer living radical polymerisation (SET-LRP). The precise control over core–shell structures is generally hindered by the polymer length that can be synthesised. Detailed studies using a variety of monomers are presented to demonstrate the versatility and limitations of SET-LRP to produce ultrahigh molecular weight polymer grafts from a spherical substrate. We show that SET-LRP is an effective technique to prepare well-defined core–shell materials with tuneable properties. The process proposed is based on copper wire, affording polymers with fewer copper contaminants, which is easily removed and recycled, proceeds at low reaction temperatures with fast kinetics, making it the process of choice in both academia and industry.