We describe herein, a general, efficient, and scalable process to design magneto-responsive thermoplastic elastomer-based (nano)­composites that can be repeatedly healed in a few tens of seconds by triggering polymer melting upon exposure to a high-frequency magnetic field. Three series of composites loaded with 1–15 vol % of Fe3O4 nanoparticles, Fe nanoparticles, or Fe microparticles were produced and characterized in depth with the aim to identify the physical properties required for two applications: (1) material healing, which we evaluate through the rewelding of precut samples and subsequent tensile tests, and (2) surface smoothening of 3D-printed objects, serving to remove superficial defects and improve their appearance. The optimal formulation consisting of a composite reinforced with 5 vol % of Fe nanoparticles ensures a high ability to heat while keeping a low viscosity in the molten state being ideal for polymer processing.

This work shows how furan ring-opening reactions were controlled by polymerization conditions to tune the cross-link density in bio-based poly(furfuryl alcohol) (PFA). The influence of water and isopropyl alcohol (IPA) on the polymerization of furfuryl alcohol, and particularly on furan ring-opening, was investigated by means of C NMR and FT-IR spectroscopy. Results indicated that formation of open structures were favored in the presence of solvents, thus leading to modification of the thermo-mechanical properties compared to PFA cross-linked without solvent. Dynamic mechanical analyses showed that when slightly more open structures were present in PFA it resulted in an important decrease of the cross-link density. Despite lower glass-transition temperature and lower elastic modulus for PFA polymerized with solvent, the thermal stability remains very high (>350 °C) even with more open structures in PFA.