Activities performed and main achievements
Optimisation of Cellulose nanocrystal (CNC) formulation
Firstly, we focused on adapting our formulations to the suspensions provided by the new manufacturer CelluForce (
https://celluforce.com/(odnośnik otworzy się w nowym oknie)) and innovating with a new preparation protocol. We focused on optimising cellulose nanocrystal (CNC) stability and processability by studying the influence of desulfation on CNCs. CNCs prepared via H2SO4 hydrolysis carry negatively charged sulfate groups on their surface.
1 These surface charges not only facilitate CNC dispersion through electrostatic repulsion but also play a pivotal role in determining their suspension behaviours and self-assembly properties.2 3 However, detailed investigations into the relationship between surface charge density, suspension dynamics, and the resulting structural colouration remain limited. By understanding this process, CNCs can be precisely tailored to create an economical, scalable and application-specific large-scale CNC manufacturing process. Using a single batch of CNCs, the variability in CNC length, width, and thickness was minimised in our studies, allowing well-controlled experiments to focus on surface charge modifications only. Among the different desulfation methods, hydrothermal treatment showed minimal effect on CNC morphology compared to NaOH or HCl treatments.
Scale-up of CNC production
The next important step was to scale up production to the kilogram level. To facilitate scale-up, the project evaluated several commercially available production lines, including different application and drying technologies. A company, Sparxell (
https://sparxell.com/(odnośnik otworzy się w nowym oknie)) has been set up to exploit the results of the project. Sparxell is enabled to scale up the production of photonic films from laboratory scale to pilot scale production.
Significant progress has been made towards kilo-scale production. Pigment production capacity was scaled up 100-fold, reaching kg-scale by testing different drying rates and temperature profiles. The coating liquid deposition process was improved, and modifications were made to the existing line to provide the necessary parameters for consistent product manufacturing. Liquid preparation and application studies were carried out. We have defined the parameters to achieve sufficiently high liquid and film quality and demonstrated repeatable pigment production over a number of trials.
The market engagement was well received and supported the launch of the Sparxell spin-out.
As part of the project, a study was conducted and published to assess the ecotoxicological effects of cellulose nanocrystalline glitter compared to conventional polyethylene terephthalate (PET) glitter. These results position CNC glitter as an environmentally friendly alternative to PET glitter, potentially reducing the ecological risks associated with microplastic pollution in soil.
The main objectives of the project—1) scaling up the production of effect pigments and glitter from several grams to kilograms, and 2) demonstrating the low carbon footprint, biodegradability, and ecotoxicity of the produced pigments—the following results have been achieved:
Scale-up
Pigment production capacity was scaled up 100-fold to kg scale by testing different drying rates and temperature profiles, fulfilling objective 1 of the project.
A spin-out company, Sparxell (
https://sparxell.com/(odnośnik otworzy się w nowym oknie)) was established enabling the scale up the production of photonic films from laboratory to pilot scale