Synthesis and characterization of shape memory epoxy-anhydride system

Thermoset polymers exhibiting shape memory properties were derived on reacting digycidyl ether of bisphenol A (DGEBA) with pyromellitic dianhydride (PMDA) in presence of a shape memory polymer precursor i.e. carboxyl telechelic poly(tetramethylene oxide) (PTAC) that was synthesized. Cure characteristics of the blends were investigated by differential scanning calorimetry and FTIR. Blends with varying proportions of DGEBA/PTAC/PMDA were studied for their flexural, dynamic mechanical and shape memory properties. The flexural strength and modulus decreased with increase in concentration of PTAC. The storage modulus and the transition temperatures (T-trans) of the systems also showed a similar trend. These polymers showed good shape memory properties. PTAC increased the modulus ratio (E-g/E-r) which in turn increased the extent of shape recovery with a concomitant diminution in the shape recovery time. An increase in temperature results in faster recovery with an increase in the extent of shape recovery. The epoxy-anhydride system possesses adequate thermal, mechanical and shape memory characteristics for possible use in smart actuator systems.