High-Performance\nResin Formulations with Ozone-Pretreated\nCorn Cob Lignin and Lysine

Nontoxic resins formulated with renewable components\nhave been\nreceiving increased attention as sustainable alternatives to petroleum-based\nresins. In this work, we demonstrate a new class of lignin-amino acid\n(LA) resins, formulated with nontoxic components that are abundant\nand can be renewably sourced from field leftovers (corn cobs) and\nlysine (from biobased sugars). NMR (<sup>1</sup>H, <sup>31</sup>P, <sup>13</sup>C–<sup>1</sup>H HSQC, <sup>15</sup>N–<sup>1</sup>H HSQC, and <sup>15</sup>N–<sup>1</sup>H HMBC), FTIR, thermogravimetric,\ngel permeation chromatography, and elemental analyses provide insights\ninto the physicochemical properties of the resins, including the presence\nof LA linkages such as C–N cross-linking. The LA resin creates\nstrong bonds between pieces of wood, metals (aluminum and stainless\nsteel), and plastics. Internal bond strengths (IBSs) of balsa wood\nand medium density fiberboard specimens glued with LA resins, measured\nusing an Instron instrument, were comparable to those bonded with\ncommercial polyurethane and polyvinyl acetate resins. Resins prepared\nwith ozone-pretreated lignin have significantly larger molar masses\nand display increased bond strengths with glued substrates as inferred\nfrom IBS measurements. This is attributed to the creation of reactive\noxygen-based functionalities in the lignin upon ozone pretreatment.\nLA resins thus show promise as a feasible and sustainable alternative\nto petroleum-based resins.