From Tree to Tape: Direct Synthesis of Pressure Sensitive Adhesives from Depolymerized Raw Lignocellulosic Biomass

We report a new and robust strategy toward the development of high-performance pressure sensitive adhesives (PSAs) from chemicals directly obtained from raw biomass deconstruction. A particularly unique and translatable aspect of this work was the use of a monomer obtained from real biomass, as opposed to a model compound or lignin-mimic, to generate well-defined and nanostructure-forming polymers. Herein, poplar wood depolymerization followed by minimal purification steps (filtration and extraction) produced two aromatic compounds, 4-propylsyringol and 4-propylguaiacol, with high purity and yield. Efficient functionalization of those aromatic compounds with either acrylate or methacrylate groups generated monomers that could be easily polymerized by a scalable reversible addition-fragmentation chain-transfer (RAFT) process to yield polymeric materials with high glass transition temperatures and robust thermal stabilities, especially relative to other potentially biobased alternatives. These lignin-derived compounds were used as a major component in low-dispersity triblock polymers composed of 4-propylsyringyl acrylate and n-butyl acrylate (also can be biobased). The resulting PSAs exhibited excellent adhesion to stainless steel without the addition of any tackifier or plasticizer. The 180° peel forces were up to 4 N cm^-1, and tack forces were up to 2.5 N cm^-1, competitive with commercial Fisherbrand labeling tape and Scotch Magic tape, demonstrating the practical significance of our biomass-derived materials.