Polymer Systems
 This project develops polymer systems (emulsion polymer, crosslinking) from biologically based sources. We also aim to synthesise these using "green" processing technology for use as resins in composite materials
Current wood composites (plywood, LVL, particleboard, MDF) still use synthetic thermosetting resins as binders (PF, UF, PVA). The development of new biologically based polymer systems for use as resins would give a composite material produced entirely from natural renewable resources.
These polymers may be similar to current resins, available as a polymer emulsion, as a dry powder or as a core-shell emulsion.
Polymer properties are determined primarily by molecular weight, which for emulsion polymers is determined by, firstly, numbers of emulsion particles and secondly, by numbers of growing polymer chains per particle (that is, by termination reactions). Many factors in the early stages of synthesis of emulsion polymers, including aggregation of growing polymer chains, critically affect final polymer properties.
Emulsion polymerisation techniques now allow synthesis of "size-controlled" polystyrene latices. Such latices are useful as seed cores for production of other structural polymers.
 It is proposed that it should be possible to create a polymer series with a comparatively rigid internal structure, surrounded by a plastic layer so that the cured polymer series systematically varies in intrinsic rigidity. The strategy therefore for this program will be to reduce a low Tg emulsion polymer adhesive to a high Tg emulsion polymer by utilising the characteristics of emulsion polymerisation processes to control the internal structure of polymer particles. The control of rigidity this approach offers will ultimately allow investigation of the underlying adhesive technology question, which is "What effect does adhesive rigidity have on the durability of the wood/adhesive interface?"
This project is to develop green technology based on using supercritical fluids (SCF) to synthesise polymer systems. Supercritical fluids, especially supercritical carbon dioxide, have merged as an alternative to the traditional solvents that are used for polymerisation reactions.
Using supercritical carbon dioxide as an alternative solvent for polymer modification or synthesis is seen as a novel approach with the potential for new knowledge in the field. The chemistry for modifying polymers will be benchmarked using aqueous chemistry systems and then carried out in supercritical fluids solvents. The purpose of using supercritical carbon dioxide is to synthesise "dry" free flowing polymers which can be blended with natural fibres to form composites. 
The projects aims in stages are:
- synthesis of polymers in aqueous and SCF solvent systems
- characterisation of these polymer systems
- assessment of these polymers for use in composite materials
Contact: Jeremy Warnes |