Casein stabilised waterborne latexes
Growing environmental regulations are enforcing the synthesis of sustainable and ecofriendly materials. While waterborne processes, as emulsion polymerisation, allow producing polymeric materials with low solvents emission, the reduction of their carbon footprint can be achieved by replacing petroleum-derived raw materials by biobased reagents. In this scenario, a new work aims to synthesise high biobased content waterborne latexes by emulsion polymerisation of two partially biobased commercial monomers (2-octyl acrylate, OA, and isobornyl methacrylate, IBOMA) in presence of previously methacrylated casein (bovine milk protein), which acts as a surfmer (i.e., an emulsifier capable of being radically polymerised).
The kinetic study of the emulsion polymerisation of OA and IBOMA allows optimising the formulation, thus resulting that the incorporation of a low fraction of a more water soluble monomer is required to reach acceptable polymerisation rates and high monomer conversion. The as-obtained films show promising performances in terms of their mechanical properties, resistance to solvents and biodegradability in organic compost, which could pave the way for the synthesis of high biobased (>75%) content binders for waterborne coatings.
The study has been published in Progress in Organic Coatings, Volume 168, July 2022.