Facile tailoring of thermal transition temperatures of epoxy shape memory polymers

A critical parameter for a shape memory polymer (SMP) lies in its shape memory transition temperature. For an amorphous SMP polymer, it is highly desirable to develop methods to tailor its T_g, which corresponds to its shape memory transition temperature. Starting with an amine cured aromatic epoxy system, epoxy polymers were synthesized by either reducing the crosslink density or introducing flexible aliphatic epoxy chains. The thermal and thermomechanical properties of these epoxy polymers were characterized by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). All the crosslinked epoxy polymers with T_g's above room temperature were found to possess shape memory properties. Overall, our approach represents a facile method to precisely tune the T_g of epoxy SMP polymers ranging from room temperature to 89 °C.