Reversibly cross-linked fullerene/polyamide composites based on Diels-Alder reaction

High-performance composites that are mechanically strong and thermally stable are widely used in many fields, introducing additional functionalities into these composites accompanied with improved physical properties can further expand their applications. In this paper, reversibly cross-linked composites consisted of aromatic poly amide (fPA) with pendent furan groups and fullerene C-60 was fabricated. The Diels-Alder (D-A) reaction between furan groups and C-60 allowed the cross-linking of fPA at moderate temperature, and the cross-linking effect greatly improved the mechanical and thermal properties of composites at a small loading (0.3 wt%) of C-60. The retro D-A reaction permitted the dissociation and reprocessing of cross-linked C-60/fPA composites at high temperature. Tensile test revealed the similar mechanical properties of reprocessed composites in comparison to their original samples, confirming the good recyclability of C-60/fPA composites. Moreover, the improved high temperature shape memory property of C-60/fPA composites as compared to neat fPA was also demonstrated. These fascinating features as well as the easy processing of our C-60/fPA composites make them promising materials for various applications.