Properties of Epoxidized Soybean Oil Modified Epoxy Resins 2: Thermal, Mechanical, and Morphological Properties

Cycloaliphatic epoxy resins were mixed with epoxidized soybean oil (ESO) and cured with cycloaliphatic anhydride. Thermal, mechanical properties and morphology of the epoxy resins were investigated by TGA, DMA, UTM, impact tester, and SEM. As ESO content increased, the tensile, flexural, and impact strengths of the epoxy resins increased and had maximum values at 10 wt% of ESO content. The morphology revealed that the impact strength increase was due to the flexible ESO aliphatic chain introduced into the epoxy network, which caused the rough fractured surface and absorbed the impact energy. Therefore it was thought that the epoxy resins with improved mechanical properties and good weatherability as well as environment friendliness and economic feasibility can be manufactured by adding a small amount of reactive ESO into cycloaliphatic epoxy resins.