Multifunctional sequential dual curing electroactive graphene Nanocomposites: Self-heating, de-icing and in-situ curing

Abstract

Dual sequential curing systems can overcome the traditional challenges of commonly amine-cured epoxy resins, such as poor thermal conformability and high volumetric shrinkage. The inclusion of click reactions allows a reduction of production times and enables a high shape-memory and in-situ curing. By reinforcing with conductive fillers, high thermal and electrical conductivity can be achieved, allowing a fast method for de-icing or self-heating. In this work a sequential dual-curing epoxy system based on thiol-epoxy chemistry and reinforced with Graphene Nanoplatelets (GNPs) in variable content is manufactured and characterized. In addition, a detailed characterization of the dual curing process has been carried out, demonstrating its sequential nature through calorimetric analysis revealing the effect of GNP content on the kinetics and extent of each of the curing stages, showcasing a direct interaction between the reinforcement and the crosslinking chemistry of the system. This system is endowed with electroactive de-icing properties by means of self-heating, reaching a heating up to 800 °C/min with a thawing as fast as 4 s with excellent shape memory. Most importantly, the second in situ curing is performed with thermoforming and form-fixing capabilities, an in-situ application of this system. Finally, the dual-curing thiol-epoxy/GNP nanocomposites developed in this work enabled energy savings of up to 98 % during the second-stage Joule curing, achieving one of the lowest volumetric energy consumptions reported for GNP-based systems. This research shows the design of a new multifunctional material and also parametrises the self-heating by Joule effect and the relation with the reinforcement dispersion quality.