The group is currently working on a joint project with the Stockman group synthesising and polymerising terpene monomers. 

300 million tonnes of polymers are produced annually, mainly derived from fossil fuels, with <5% being sourced from renewable sources. The rapid depletion of these fossil fuels, along with their damaging contribution to the environment, means the need to source materials from renewable sources has greatly increased. Terpenes are abundant, inexpensive and are obtained from a renewable feedstock. Despite containing alkene moieties terpenes do not readily undergo radical polymerisation. Therefore the research carried out in our group focusses on the synthesis and polymerisation of new terpene derived monomers utilising radical polymerisation techniques, ring opening polymerisation and condensation polymerisation for a number of applications.

Dispersion polymerisation is used by the group to produce particles with highly controlled morphologies.

Large molecules such as polymers are often insoluble in scCO₂. Thus, the development of stabilisers to aid the dispersion of the growing polymer chain in the supercritical phase is a key area of research within the group. 

The key advantage with this process is that high molecular weight polymers are obtained as clean, dry, solvent-free fine powders. Using RAFT control, we have recently created unusual nanostructured polymeric microparticles using dispersion polymerisation in CO₂.

SEM image of polymer particles produced using a stabiliser

 

SEM image of individual polymer particles

 

Internal morphology of block copolymer particles

 

 

The group has recently purchased a rheometer with high pressure capabilities. This can be used to study the mechanical properties of polymers as they are processed/synthesised in scCO₂. As scCO₂ is known to greatly decrease the viscoisty of some polymers, this is a valuable tool for material characterisation.