Polymer–Clay Nanocomposites Prepared in Miniemulsion Using the RAFT Process
This chapter is a review on polymer-clay nanocomposites (PCNs) prepared in miniemulsion using the reversible addition-fragmentation chain transfer (RAFT) process.
One of the most interesting research areas in nanotechnology is the inclusion of nanoparticles in polymers in order to enhance their physical properties e.g. thermal stability, barrier properties and mechanical properties. In the early 1990s the Toyota research group showed that the hydrated cations within the clay layers can be replaced by alkyl ammonium compounds. A reactive clay modifier leads to a strong interfacial adhesion between the clay and the polymer, and subsequently the exceptional mechanical properties during load bearing. The use of tailor-made transfer agents in free-radical polymerisation reactions allows one to achieve control of the polymerisation process. This results in polymers with low polydispersity indices and predictable molar masses. The discovery of the controlled polymerisation techniques, and in particular RAFT agents, was a milestone achievement. RAFT polymerisation now allows the preparation of polymer architectures that were never before envisaged to be possible. Thus, a combination of RAFT technology and clay nanotechnology for the synthesis of PCNs by RAFT-mediated polymerisation can allow the preparation of tailor-made materials with specific properties for niche applications.