Adhesives Synthesized from Wood WasteS. Himmelstein | November 16, 2018
High-performance pressure-sensitive adhesives (PSAs) have been produced from lignocellulosic biomass, a material burned or otherwise discarded by paper manufacturers.
University of Delaware researchers first developed a robust method to produce functional phenols by depolymerizing poplar wood lignin via selective hydrogenolysis using a commercial ruthenium-based catalyst in methanol. The two main products — 4-propylsyringol and 4-propylguaiacol — were purified from the catalyst and the reaction mixture by an inexpensive solvent extraction method. Purified products then reacted with either acrylate or methacrylate, and the functionalized derivatives were polymerized by a scalable reversible addition — fragmentation chain-transfer process to yield this new class of adhesive materials.
The adhesive's stickiness can be tuned simply by modifying the catalyst. The biomass-derived PSAs exhibited properties that rival those of PSAs produced from petroleum, including high glass transition temperatures, robust thermal stabilities, excellent adhesion and mechanical properties that may allow them to serve as renewable replacements for existing PSAs.
The polymer synthesis process is described in ACS Central Science.