Materials
tasks, it will provide moulds to verify the processability of the new materials. At the same time, Promolding will handle pilot- scale compounding, as well as analysing the electrical and mechanical properties of the materials.
Materials specialists in the project include: Lati, which makes electrically and thermally conductive compounds; Timcal, a leading producer of graphite and carbon black; Aimplas, a research organisation with experience in preparing nanocomposite compounds; and MB Proto, a company involved in rapid prototyping technologies.
Manufacturers in the consortium include: electronics giant Philips; and Aero Engine Controls, a joint venture between Rolls- Royce and Goodrich.
Production boost The first step in the project is to take production of the materials up to something approaching industrialisation – but, being such specialised materials, these volumes are not exactly astronomical. At the outset, the team was capable of making 10g batches, but later raised this to 250g – with remarkable success. Production is now hovering at the 1kg scale, and will soon be upgraded to 5kg. The eventual target is to raise this to 25kg.
Nano particles are notoriously difficult to mix with plastics. For this reason, the project will attempt to develop a range of pre-mixed graphene compounds (known as masterbatches). This ensures that a traditionally difficult step of the process – incorporating the graphene into the plastic matrix – has already been done.
The graphene-enhanced plastics are made into pellets and processed in the conventional way, to produce plastic components. Nanomaster will look at two commonly used processes – injection moulding and compression moulding.
The project will focus on lab-scale compounding of graphite-polypropylene (PP) compounds. The specifics of how the compounds are made will be key to their eventual success. There will also be computer simulation work, to allow effective scale-up of the process from lab scale to pilot scale production.
In addition to taking the pre- made graphene and dispersing it within a masterbatch, another aim of the project is to determine whether an expanded or partially exfoliated graphite can be further exfoliated during the compounding process.
Nanomaster will also attempt to develop materials for use in additive manufacturing, also known as
Fig. 2. Graphene is produced under highly specialised conditions.
Picture courtesy: National University of Singapore.
3D printing, which relies on building up components in a ‘layer-by-layer’ fashion, to create products that would be impossible to make in conventional ways.
These kinds of techniques – such as selective laser sintering (SLS) and fused deposition modelling (FDM) – were originally used to make ‘rapid prototyping’ models. More recently, they have been used to make limited-run finished products.
The mechanical properties of these components are not generally very high. So more robust materials – such as those being developed by Nanomaster – could expand the scope of additive manufacturing. ●
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