The fuel consumption of commercial aircraft has been reduced by about 20% due to an increased use of lightweight, plastic-based, composites. Future aircraft will be comprised of even higher percentages of composites. In addition to light-weighting enabling greater fuel efficiency, it is recognised that composite alternatives to metals will be essential for full electrification of cars to be realised. The composites are typically blends of epoxy resins, which are a form of thermoset, and engineering thermoplastic polymers. Our aim is to develop models that describe how blending and hardening couple to form nano and microscale structures, to guide the formulation of the next generation of composites.
The blends initially consist of the unreacted epoxy and engineering thermoplastic in a homogeneous, liquid state. The thermosets are then cross-linked in situ with curatives, typically amines, whilst being heated. The increasing molecular weights of the epoxy/amine components cause the blends to phase separate due to a loss of entropy. Phase separation is a dynamic, non-equilibrium process, where both the phase behaviour and the motion of individual chains determine how fast the phase separation proceeds and the length scales of the structures that dominate.
Our research program aims to develop computational models that couple the statistical thermodynamics describing the phase behaviour with the kinetics of both chemical reactions and the molecular motion of branched polymers. Our work is motivated by recent experimental observations that currently lack a physical interpretation. Our aims in this project are to:
To develop a non-equilibrium model in order to model the kinetics of phase separation and predict the flow response of the blends. The latter will enable us to compare theory with experiments conducted on curing samples at Solvay, the project partner.
To use the Monte Carlo model to parameterise coarser grained methods for modelling structure and structure evolution in the presence of interfaces, which is of particular importance when the blends are impregnated into carbon fibres.
To significantly increase code efficiency through parallelisation using Graphical Processing Units, in order to model longer time processes for larger systems, making results more experimentally relevant.
To support neutron scattering experiments, being conducted by collaborators in Lyon, which will be essential to verify and refine our modelling.
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