Preparation and characterization of novel vinyl ester formulations derived from cardanol

In this study, two commercially available epoxidized cardanol resins, NC 514 with approximately two epoxies per molecule and LITE 2513HP with approximately one epoxy per molecule were methacrylated and the methacrylated NC-514 resin (NC514VE) was used as the cross-linker unit and the mono-functional methacrylated LITE monomer (LITEVE) was used as the reactive diluent in both conventional DGEBA vinyl ester resin (DGEBAVE) and in NC514VE resin at changing concentrations. Resin formulations of NC514VE using styrene as the reactive diluent were also prepared. The methacrylated products were characterized via spectroscopic techniques like FT-IR and ¹H NMR spectroscopy. The viscosities of the liquid resin mixtures at 30 °C were examined and the curing behavior was analyzed via Differential Scanning Calorimetry (DSC). After the cure, the thermo-mechanical properties of the resins were determined via Dynamic Mechanical Analysis (DMA) and mechanical properties were determined via tensile tests. According to thermal gravimetric analysis (TGA) data, at 30 wt% co-monomer content, the temperature of 5% degradation were in 270-300 °C temperature region meaning that the samples were stable until this temperature range. The effect of the diluent content and the structures of the different monomers on both liquid resin and cured resin properties were also evaluated.