Shape memory poly (ether ether ketone)s with tunable chain stiffness, mechanical strength and high transition temperatures

ABSTRACT Shape memory polymers, with intrinsic enhanced strength and high thermal stability, are highly demanded in aerospace, engineering manufacturing, and spatial structures. In this paper, we develop a series of thermoplastic shape memory poly(ether ether ketone)s (PEEKs) for the first time, achieving an excellent shape memory ability, high strength, and great thermal stability via a condensation polymerization. Through tuning the proportion of different bisphenol monomers, the flexibility of molecular main chains is adjusted, resulting in the regulation of transition temperature and mechanical performances. Synthesized PEEKs possess the tunable Tg from 143.3°C to 178.6°C, the enhanced tensile strength from 48.4 to 65.1 MPa, and Young’s modulus from 0.45 to 1.8 GPa, in addition to the excellent heat-triggered shape memory effect, as indicated by high recovery ratio (94%–98.9%) and fixity ratio (over 99.5%). Furthermore, after incorporating the magnetocaloric Fe3O4 particles, the composites exhibit remotely noncontact magnetic-triggered shape memory behaviors (Fe3O4 content over 10 wt%). These synthesized Tg tunable shape memory PEEKs and the composites have wide utilization potential in fields of engineering and aerospace structures, owing to the excellent mechanical properties, thermal stability, unique programmable deformation ability, and remote actuation.