Development of an Electroactive and Thermo-Reversible Diels-Alder Epoxy Nanocomposite Doped with Carbon Nanotubes

• Published in: Polymers Vol. 15; no. 24; p. 4715
• Main Authors: Lorero, Isaac, Rodríguez, Álvaro, Campo, Mónica, Prolongo, Silvia G
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 15-12-2023; MDPI
• Subjects: Analysis; Brittleness; Carbon; Carbon nanotubes; Chemical synthesis; Chemistry; Composite materials; Conductivity; Crosslinking; Diels-Alder reaction; Electric properties; Electrical resistivity; Electroactivity; Epoxy resins; Graphene; Manufacturing; Mechanical properties; Methods; Nanocomposites; Nanoparticles; Nanotubes; Ohmic dissipation; Percolation; Polymers; Resins; Resistance heating; Silver; Thermal properties; Thermoforming; Spain; Germany; CAN; electroactive polymer; shape memory; Diels–Alder thermoset; nanocomposites
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym15244715

The manufacturing of Diels-Alder (D-A) crosslinked epoxy nanocomposites is an emerging field with several challenges to overcome: the synthesis is complex due to side reactions, the mechanical properties are hindered by the brittleness of these bonds, and the content of carbon nanotubes (CNT) added to achieve electroactivity is much higher than the percolation thresholds of other conventional resins. In this work, we develop nanocomposites with different D-A crosslinking ratios (0, 0.6, and 1.0) and CNT contents (0.1, 0.3, 0.5, 0.7, and 0.9 wt.%), achieving a simplified route and avoiding the use of solvents and side reactions by selecting a two-step curing method (100 °C-6 h + 60 °C-12 h) that generates the thermo-reversible resins. These reversible nanocomposites show ohmic behavior and effective Joule heating, reaching the dissociation temperatures of the D-A bonds. The fully reversible nanocomposites (ratio 1.0) present more homogeneous CNT dispersion compared to the partially reversible nanocomposites (ratio 0.6), showing higher electrical conductivity, as well as higher brittleness. For this study, the nanocomposite with a partially reversible matrix (ratio 0.6) doped with 0.7 CNT wt.% was selected to allow us to study its new smart functionalities and performance due to its reversible network by analyzing self-healing and thermoforming.