Bio-fabrication of sustainable functional bacterial cellulose aerogel for building insulation

Climate change is undoubtedly the greatest challenge of our generation. The World Green Building Council is catalysing the construction and property industry to lead the transition to a net zero carbon-built environment. In the UK, the operation of buildings accounts for around 30 percent of emissions, mainly from heating, cooling and electricity use. Heating and cooling in buildings accounts for over 10% of global energy consumption. There is an increasing emphasis on energy efficiency and cutting carbon emissions from our homes and workplaces. The UK Government is keen to see energy efficiency in buildings improved and various initiatives and schemes offered for insulating domestic homes for building energy improvements. However, industrial synthetic insulation materials, such as polystyrene and polyurethane, dominate the building insulation industry. They are oil based polymerised polystyrene and the manufacturing of those materials is an energy intensive process. Moreover, all the synthetic insulation foams are not vapour permeable, which can cause dampness as well as decay in the wall. Some of them will release toxic hydrogen cyanide and isocyanates during a fire. Although interest in the use of bio-based insulation products is steadily increasing, the efficient thermal insulation renewable or biobased materials such as wood chips and sheep wools and recycled paper are generally inferior to that of fossil fuel-based materials such as expanded polystyrene and polyurethane foams. To meet the demand for a sustainable and net zero carbon building industry, there is a pressing need for innovative insulation materials that would facilitate low energy consumption and a minimal impact on the environment.

This NIA proposal is to make breakthroughs in how to use renewable and degradable resources to replace petroleum derivatives production technology, reduce environmental damage, and achieve sustainable development. This proposal is a first step to transform the manufacture of building insulating materials using biotechnology to develop novel cellulose-based aerogel to reduce fossil energy demand and contribute to net zero carbon buildings. The fundamental challenge is to develop novel low cost and low energy intensive ambient drying methods to produce functional bacterial cellulose aerogels with flame retardant, insulation, and anti-bacterial properties, which will have key applications in the field of construction materials. The low cost and low energy intensive drying method using sodium bicarbonate will be studied. The effect of the processing and in particular, the challenges related to the removal of the solvent to generate low-density foams and aerogels on heat transfer properties will be investigated.

An In-situ adaptive modification approach will be applied to address the challenges for using bacterial cellulose aerogel by incorporating functional chitosan in building insulation applications to provide the desired photo-catalytic self-cleaning, antibacterial and flame retardant properties. The interdisciplinary nature of proposal will build a real network for Bioengineering, building physics and Industry partners to work together and conduct research outside of their own discipline area to create a new generation of renewable and degradable bio-cellulose aerogel for energy efficient building. This research is currently at proof-of-concept stage and has high potential for impact with a wide array of applications in the future. This approach will enable the manufacture of insulation materials utilising waste, with little energy input and in ways which are carbon sequestering and non-polluting. It has enormous potential to produce renewable thermally insulating materials with significantly better heat transport properties than the currently commercially dominating materials such as expanded polystyrene, polyurethane foams, and glass wool.