(769b) Preparation and Characterization of Cardanol Based Vinyl Ester Resins As Cross-Linker Units

Cardanol which is the main component of the thermally threated cashew nutshell liquid is a versatile monomer which combines a phenyl ring with a C15 alkyd chain with different degrees of unsaturation. Because of its unique structure and reactive functionalities, cardanol based building blocks has a growing potential to supply aromatic building blocks for many applications such as corrosion prevention coatings. In this study, cardanol glycidyl ether (LITE 2513HP, Cardolite®) was chemically modified from the unsaturation sites of the side chain by means of epoxidation in the presence of hydrogen peroxide and formic acid. The structure of the modified cardanol resin (SCECGE) was confirmed via proton nuclear magnetic resonance, Fourier Transform infrared spectroscopy, and epoxy equivalent weight titrations. This modified resin was cured with petroleum based epoxy hardener 4-4’-methylene biscyclohexanamine (PACM). Also for comparison, another cardanol based di-phenol di-epoxy resin NC514 (Cardolite®) and petroleum based epoxy resin diglycidyl ether of bisphenol-A (DGEBA) were thermally cured with listed epoxy hardeners at stoichiometric ratios. The extent of curing reaction and curing mechanism of different epoxy/amine systems were explored via mid-IR techniques and differential scanning calorimetry (DSC) to determine that the secondary epoxides are not as reactive as the primary glycidyl epoxides. The glass transition, modulus, and strength of the cured SCECGE resins were lower than that of the NC514 and DGEBA because of the lower extent of reaction of the secondary epoxides. In addition, the water barrier properties of this cardanol based SCECGE resin were also determined via contact angle and, water and vapor sorption studies to explore the coating performance of the material.