A new shape memory epoxy resin with excellent comprehensive properties

In this article, a new type of epoxy resin, diglycidyl ether of 9,9-bis [4-(2-hydroxyethoxy) phenyl] fluorine (DGEBEF) was successfully synthesized and characterized by 1H-NMR, FTIR, and FDMS analyses. The kinetics of DGEBEF cured with 4,4′-diamino diphenyl sulfone (DDS) was investigated by nonisothermal differential scanning calorimetry and thermal stability of the cured resin was characterized by thermogravimetric analysis. The DGEBEF/DDS system exhibits excellent processability, mechanical strength, and toughness, high thermal stability and low water absorption. Glass transition temperature (Tg) of the cured epoxy was 170 °C determined by DMA. The ratio of the storage modulus of the cured resin at glassy state to that at rubbery state was as large as about 400, indicating its potential applications as shape memory material. The excellent shape memory properties were confirmed by fold-deploy shape memory and tensile-shrinkage tests. The shape fixed ratio was 99 %. and the shape recovery ratio was nearly 100 % after 30-s recovery at 185 °C in the fold-deploy shape memory test. In the tensile-shrinkage test, the recovery stress is 2.5 MPa at the strain of 25 % and temperature of 185 °C, and both the shape fixed and shape recovery ratios maintained at about 99 % after six test cycles.