Preparation and characterization of cardanol based vinyl ester resins as cross-linker units

In this study, two cardanol based epoxidized resins, NC514 with less than two epoxies per molecule and side chain epoxidized cardanol glycidyl ether (SCECGE) with approximately 2.45 epoxies (1.0 phenolic+1.45 aliphatic epoxies) per molecule were methacrylated. The methacrylated versions of cardanol based NC514 (NC514VE) and SCECGE (SCECGEVE) epoxy resins were used as cross-linker units in vinyl ester formulations with methacrylated lauric acid (MFA) and styrene (ST) as bio-based and synthetic based reactive diluents respectively, at various concentrations (10–40 wt%). The curing reactions of the resins were studied via FTIR and the extent of polymerization was determined for different cross-linker units in the presence of ST and MFA. Our mechanical and thermomechanical characterizations showed that VER formulations prepared with cardanol based SCECGEVE cross-linker unit have significantly improved properties than the samples prepared with commercially available counterpart NC514VE using either reactive diluent. These properties of SCECGEVE were also comparable with to that of methacrylated petroleum-based diglycidyl ether of bisphenol A vinyl ester (DGEBAVE) formulations unlike NC514VE formulations due to more effective side chain functionalization and cross-linking.