Evaluation and Formulation of Hybridized Biobased Precursors as Anticorrosive Surface Coatings

This study focuses on the synthesis of an oligomeric diepoxy resin (EVAC) derived from two diverse biomass sources, cashew nutshell liquid and lignin, and its evaluation as a major component in an anticorrosion surface coating. EVAC structural verifications were performed via spectroscopic and chromatographic methods. EVAC was mixed with diglycidyl ether of bisphenol A (EPON-828) at varying ratios and cured with 5,5'-methylene difurfurylamine (DFDA) and diethylmethylbenzenediamine (Epikure W). Thermally cured blends containing DFDA demonstrated improved moduli and char yields relative to those containing Epikure W. Although the replacement of EVAC with EPON-828 resulted in a reduction in the glass transition temperature and the strength, desired hydrophobicity, flexibility, and adhesion for coatings applications were imparted. Additionally, biobased DFDA demonstrated improved coatings and corrosion performance relative to Epikure W without significantly affecting network performance. Markedly, EVAC/DFDA-based formulations demonstrated high gloss, substrate compatibility, adhesion (5B), impact resistance (>160 lb.-ft), and durability characteristics.