The construction industry accounts for ~37% of global emissions and is notoriously slow to adopt low carbon approaches. Vector Homes, a UK sustainable housing innovator, is working with advanced materials researchers at the University of Manchester, to develop sustainable materials for the built environment. This includes a graphene-enhanced, fire-retardant thermal insulation foam, offering an alternative to traditional insulation foams.
“Most insulation foams are made fire-resistant by adding toxic halogens like chlorine or bromine, which change properties such as boiling point or stability. They are terrible for the environment, but they are essential to fire safety” says Vicente Orts, Senior Scientist at Vector Homes.
Whilst non-toxic additives exist, they require high doses to achieve fire resistance, which can negatively impact properties such as weight and strength. Vector Homes’ patented formulation uses graphene as an additive. Graphene is non-toxic and only requires a small amount to make the foam fire retardant, whilst also improving its strength and insulation. The formulation was shown to perform well in a lab setting, where it achieved low weight-per-meter density and a closed cell structure, an essential component of insulating materials.
Vector Homes were keen to explore a continuous extrusion process where polymers, graphene and supercritical CO2 were continually inputted into an extrusion device, combined and forced through a mould to emerge from the other end. However, in trials the foam did not achieve their required levels of quality and consistency so scaling a repeatable and reliable production process proved to be a challenge.
Through a Measurement for Business (M4B) project, NPL examined the continuous extrusion process in detail, exploring a variety of production parameters and ways to measure quality of the foam at various points. The objective was to help Vector optimise parameters such as ratio of feedstocks, gas injection and temperature across the process to achieve a consistent product output.
NPL provided a detailed list of 63 techniques for measuring foam characteristics. Examples included in-line measurements for temperature across the process, and offline measurements, such as optical measurements of foam sections for size, density and cell structure. NPL provided a report summarising these techniques and proposed a variety of production approaches, with pros and cons for each.
“Ultimately, the thing the project showed us was that continuous extrusion was not right for this application, and that a batch process was much better suited. This has saved us a lot of time and money by avoiding pursuing a dead end.” says Orts. “The work also gave us valuable insights into measurement approaches, such as cell analysis techniques, to understand material structure, which is helping us optimise the elements of the process we are taking forward.”
The data gleaned from the project supported a successful grant application, in collaboration with an industrial partner that produces fire retardants. This is now taking the process into a real industrial production system and making the leap from technology readiness level (TRL) level 4 to 7/8.
“The data from NPL was integral to the success of this grant application,” says Orts. “It allowed us to justify why we were doing things in a certain way and gave confidence to the funders and our partner about our technical capability and route to commercialisation.”
The hope now is that the foam will become a commercial product that could dramatically reduce the toxic chemicals used in fire-retardant materials required by nearly every building in the world.
The quality of the work and calibre of the NPL scientists was very high. You can tell the NPL team were very smart and knew what they were doing. It’s the best resource we could receive. The M4B project quickly put us onto the right track for developing the right production system for our sustainable graphene-enhanced insulation foam, whilst also giving us a lot of useful data to optimise the process and to validate our approach to future partners and funders.
Vicente Orts, Senior Scientist - Vector Homes