Effect of clay and alumina-nanowhisker reinforcements on the mechanical properties of nanocomposites from biobased epoxy: A comparative study

The biobased epoxy nanocomposite materials containing functionalized vegetable oils (FVOs), such as epoxidized linseed oil (ELO) and epoxidized soybean oil (ESO), were processed with organomontmorillonite and silanized alumina nanowhiskers. The certain amount of diglycidyl ether of bisphenol F (DGEBF) was replaced by ELO or ESO in the matrix. The selection of the DGEBF, FVO, an anhydride curing agent, and organomontmorillonite clay/alumina nanowhiskers resulted in an excellent combination, to provide new biobased epoxy nanocomposites showing a high elastic modulus, a high glass transition temperature, and a high fracture toughness with larger amounts of FVO. The Izod impact strength and fracture toughness of biobased neat epoxy were significantly improved depending on FVO, when phase separation was observed. The phase separation did not occur with the addition of exfoliated and intercalated clay nanoplatelets. The fracture toughness and the critical energy release rate of intercalated clay nanocomposites were higher than those of exfoliated clay nanocomposites. This was correlated to the rougher fracture surface area observed by scanning electron microscopy.