Curing kinetics and shape-memory behavior of an intrinsically toughened epoxy resin system

A diglycidylether of propoxylated bisphenol-A with two oxypropylene units (DGEBAPO-2) was prepared, and the structure was characterized by FTIR, 1 H NMR, and ESI–MS, and a flexible curing agent 2-methyl-1,5-pentanediamine (MPDA) was used to obtain an intrinsically toughened network for potential shape-memory application. The curing kinetics of DGEBAPO-2/MPDA was systematically investigated by using both non-isothermal and isothermal DSC methods; in addition, the dynamic mechanical property, mechanical property, and shape-memory property were investigated by DMA, tensile experiment, and quantitative shape-memory evaluation method. The results showed that Šesták-Berggren model and Kamal model were able to well describe the non-isothermal curing reaction rate and isothermal curing reaction rate, respectively. Tensile test at 49 °C indicated that the cured DGEBAPO-2/MPDA combined a relatively large elongation at break of 95.53 ± 2.27 % with a relatively large tensile stress of 6.33 ± 0.11 MPa. Quantitative shape-memory evaluation revealed good shape-memory properties of cured DGEBAPO-2/MPDA with shape fixity of 98.88 ± 0.04 % and shape recovery of 96.67 ± 6.91 %.