Unique Shape Memory Elastomer Associated with Reversible Sacrificial Hydrogen Bonds: Tough and Flexible When below Its Tg

Thermally induced shape memory polymers (SMPs) are fragile and brittle when cooling to a low temperature to generate temporary shapes. In the present study, the authors implement a new design strategy for fabricating elastomeric SMPs with low‐temperature flexibility by engineering reversible sacrificial hydrogen bonds into a chemically crosslinked network. Compatible, amorphous, hindered phenol moieties (Irganox 1010) are incorporated into epoxidized natural rubber (ENR) and the ENR composites are cured with zinc diacrylate (ZDA). Such reversible sacrificial bonds can rupture prior to the rupture of the bonds of the crosslinked network during stretching, which will dissipate energy and facilitate reorientation of the rubber chains. Based on the functional mechanisms, ENR composites exhibit unusual toughness and flexibility and can undergo large deformations even when below their T g . Irganox 1010 can also be used to tune the glass transition temperature ( T g ) and improve the chain mobility of the elastomer sample by providing sufficient intermolecular hydrogen bonding interactions. ENR composites demonstrate thermally triggered shape memory performance. Moreover, the dissociation/reformation of hydrogen bonds upon stretching/cooling can endow the elastomer sample with unique reversible plastics shape memory (RPSM) performance. These SMPs possess excellent shape fixity and recovery.