Thermo-mechanical properties and shape memory behavior of self-crosslinked epoxidized natural rubber (ENR)/poly(ethylene-co-acrylic acid) (EAA)/poly(ε-caprolactone) (PCL) blends

Abstract

Shape memory polymer (SMP) is a smart material which can recover to its original shape after being deformed into a temporary shape when it receives stimuli. Polymer blending is an effective way to develop a new SMP with desired performance properties. In this study, SMP based on epoxidized natural rubber(ENR)/poly(ethylene-co-acrylic acid)(EAA)/poly(ε-caprolactone)(PCL) ternary blends was prepared via a melt blending, and a subsequent compression molding at 180℃. DMA, gel content analysis, ODR and FT-IR showed that blends form a crosslinked network via a reaction between epoxy group of ENR and carboxylic groups of both EAA and PCL during the compression molding. DMA and DSC results revealed that there are two sudden drops in the storage modulus at well-separated temperatures corresponding to the crystalline melting transition of EAA and PCL in the crosslinked network. These blends exhibit triple shape memory behavior with two different temporary fixing shapes and step-wise shape recovery.