Menthol-Based Hydrophobic Eutectic Solvents as Green Plasticizers for Biobased Acrylic Polymers

While the polymer industry has gained importance in the last decades, many related environmental issues have appeared, caused by oil-based monomers, unsustainable polymerization processes, and toxic additives, among others. For instance, plasticizers commonly used in acrylic polymers often qualify as volatile organic compounds (VOCs), raising concerns due to their contribution to indoor air pollution, regulatory restrictions, and potential health risks. In this work, we explore a series of menthol-based hydrophobic eutectic solvents (HESs) as green alternatives to conventional organic plasticizers for acrylic films based on biobased isobornyl methacrylate (IBOMA), 2-octyl methacrylate (2-OMA), and their copolymers synthesized via miniemulsion polymerization. The biobased films were thoroughly characterized to assess their chemical structure, thermal, adhesive, and mechanical properties and their performance in a potential application as therapeutic patches, leveraging the inherent bioactive properties, of the HESs. We have found that the plasticizer effect on these biobased polymers could be controlled by the polarity of the hydrogen bond donor and the vapor pressure of the individual components in the eutectic mixture. These findings highlight the potential of menthol-based HESs as multifunctional, sustainable plasticizers, paving the way for environmentally friendly alternatives in advanced acrylic materials.