Bio-Based Epoxy Binders from Lignin Derivatized with Epoxidized Rapeseed Fatty Acids in Bimodal Coating Systems

Abstract

In the recent decade, a strong push toward development of more biobased binders for coating applications as part of the transition toward independence from nonrenewable fossil-based raw materials has been seen. Here we present a biobased epoxy lignin/rapeseed fatty acid derivative (eFA-L), which has been applied in coating systems, leading to coatings with >97% biobased content and Y = 130 MPa. To approach the strength of classical epoxy systems, a series of bimodal systems, containing low molecular weight adducts of biobased diglycidyl furan-2,5-dicarboxylate (DGFDC) and fossil-based diglycidylether bisphenol A (DGEBA) were prepared. In these bimodal systems, it was shown that DGEBA contributes to higher mechanical strength compared to DGFDC at equivalent cross-linking density, which was attributed to increased π–π stacking interactions. The biobased bimodal binder system composed of eFA-L and DGFDC (30 wt %) resulted in a coating with a biobased content of 93 wt %, Y = 440 MPa, and T g > 50 °C. Better mechanical properties (Y = 700 MPa) were achieved by use of DGEBA (30 wt %), but it results in a significant reduction in biobased content to 62 wt %.

Solvent Fractionation and Depolymerization Provide Liquid Lignin Fractions Exploited as Bio-based Aromatic Building Blocks in Epoxies

“…Overall, the combined process of sequential fractionation and hydrogenolysis enabled the production of tailored lignin-based epoxy networks with Young’s moduli up to 10 times higher compared to epoxy-modified lignin prepared directly from KL . Furthermore, plastic deformation (Figure S44) during cyclic load was, for all samples and strain rates, observed to be below 0.75%.…”

Organic transformation of lignin into mussel-inspired glues: next-generation 2K adhesive for setting corals under saltwater

“…This leads to a decrease in both inter-and intramolecular H-bonding capabilities, which appears to be one of the vital supramolecular modes for both dynamic network cohesion and adhesion properties. 61,62 Hydrogen bonding of hydroxy groups in an inherently hydrophobic environment, such as the aromatic lignin structure, drives interactions through the hydrophobic (entropic) effect, which is well known in water-based self-assembly and becomes particularly important when targeting wet or underwater adhesives. [63][64][65][66][67][68][69] For instance, the biological adhesive system from blue mussels (Mytilus edulis) utilizes the aromatic hydroxyl groups from the 3,4-dihydroxy-L-phenylalanin (L-DOPA) residues present in various mussel foot proteins (mfps).…”

“…This leads to a decrease in both inter- and intramolecular H-bonding capabilities, which appears to be one of the vital supramolecular modes for both dynamic network cohesion and adhesion properties. 61,62…”

Lignin Phosphate: A Biobased Substitute for Zinc Phosphate in Corrosion-Inhibiting Coatings

“…Figure illustrates the distinctive structure of lignin with various phenylpropanoid units ( p -coumaryl, coniferyl, and sinapyl alcohols) joining together with different linkages. The aromatic structure of kraft lignin comprises phenolic, alcoholic, and ether functional groups, rendering it responsive to various functionalization processes like amination, sulfonation, phosphorylation, acylation, and epoxidation . These processes facilitate the alteration of its chemical properties, thereby improving its compatibility with diverse materials.…”