Nanocomposites based on MWCNT and nanoclay: Effect of acrylated epoxidized soybean oil on curing and composite properties

Abstract

UV and thermal-curing hybrid epoxy adhesives are generally developed with a combination of epoxy acrylates and thermal-curing epoxy resin. This study modified bisphenol-A type epoxy resin (ER) with acrylated epoxidized industrial crop soybean oil (AESO) to obtain a dual-curable epoxy system. Hydroxylated multi-walled carbon nanotube (MWCNTOH) and montmorillonite-type nanoclay (NC) first was used as nano reinforcement in this system. Both thermal and UV-curing were applied to composites. Tensile and hardness tests, thermogravimetric analysis (TGA), and four-point probe electrical conductivity measurements were used for the nano- composite characterization. Although (UV+thermal) curing increased the thermal strength of the nanocomposites, it caused a decrease in their electrical conductivity and moisture absorption. The highest tensile strength values were obtained as 107 MPa and 97 MPa for thermally cured 1.5 wt% MWCNTOH and 2 wt% NC composites, respectively. The effect of the AESO ratio on UV curing of nanocomposites was investigated and 10 % was found to be the most suitable. MWCNTOH composites also exhibited the highest electrical conductivity with a percolation threshold of 1.5 wt%. The effect of hydrothermal aging on thermal and electrical conductivity properties showed that only T5 and T10 values of thermally or (UV+thermally) cured MWCNTOH and NC composites decreased, T50 values did not change significantly.