CHAMPION’s Work Package 3 on lab-scale synthesis of novel bio-based polymers and materials has recently completed its tasks. It has explored the potential of so-called aza-Michael (AM) chemistry as a tool to ‘click’ bio-based building blocks together to create polymeric functional additives for home care products and resin formulations for coatings and adhesives. The results are a big step forward to the primary objective of finding safer and more sustainable alternatives to technologies reliant on harmful chemicals and fossil feedstocks.
The University of York has focused on using AM chemistry to attach small functional groups to bio-based polymers. These water-soluble products have been evaluated by project partner Unilever for their effectiveness as additives in home care formulations, with further testing ongoing.
Wageningen Research have applied AM chemistry to convert the bio-based diamines developed in Work Package 2 (described above) into materials suitable for protective surface coatings, e.g. for furniture or car interiors. The AM reaction is relatively fast, even at moderate temperatures. When the reactive components are mixed and then applied on a substrate such as wood, leather or plastic, a polymer network forms, thereby creating a material whose properties are dictated by the chemical structure of the reacting components. Like well-known reactive resin systems such as epoxy/amine and isocyanate/polyol combinations, the AM reaction is a ‘click’ reaction, meaning that chemical bond formation is not accompanied by the liberation of small compounds that may cause health issues or material defects.
One of the challenges was the high viscosity of the bio-based reaction partners of the diamines. This made mixing and casting of the AM resin formulations difficult. Adding a volatile organic solvent was not considered due to the potential negative health effects caused by exposure to evaporating solvents. Instead, the issue was solved by adding a non-toxic diluent to the formulation, which reacts with the other resin components and integrates into the final polymer network.
In the project’s final phase, industry partners will take the lead in conducting advanced performance testing to rigorously evaluate the efficacy and sustainability of these innovative bio-based polymers and materials in real-world applications.