Shape Memory Properties of Epoxy/PPO–PEO–PPO Triblock Copolymer Blends with Tunable Thermal Transitions and Mechanical Characteristics

Abstract

In this paper, we report a simple method to prepare novel, transparent, hard-tough and hard-flexible shape memory and soft-flexible epoxy polymers based on poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (PPO-PEO-PPO) triblock copolymer (TBCP) and diglycidyl ether of bisphenol-A (DGEBA)/4,4'-diaminodiphenylmethane (DDM) system. The PPO-PEO-PPO triblock copolymer was used to tailor crosslink density and flexibility in epoxy thermosets and thereby their glass transition temperature (Tg). The formed blends exhibit a phase separated morphology. The phase separation was initiated by immiscible PPO blocks via self-assembly. Three types of shape memory polymers, viz. stiff, intermediate and soft-flexible epoxy systems, with entirely different physical and mechanical properties were prepared only by adjusting the blend composition. All the blends were UV resistant, thermally and dimensionally stable and could be used for various outdoor applications. To the best of our knowledge, n...