Among smart materials, self-healing is one of the most studied properties. A self-healing polymer can repair the cracks that occurred in the structure of the material. Polyketones, which are high-performance thermoplastic polymers, are a suitable material for a self-healing mechanism: a furanic pendant moiety can be introduced into the backbone and used as a diene for a temperature reversible Diels-Alder reaction with bismaleimide. The Diels-Alder adduct is formed at around 50 °C and broken at about 120 °C, giving an intrinsic, stimuli-responsive self-healing material triggered by temperature variations. Also, reduced graphene oxide (rGO) is added to the polymer matrix (1.6–7 wt%), giving a reversible OFF-ON electrically conductive polymer network. Remarkably, the electrical conductivity is activated when reaching temperatures higher than 100 °C, thus suggesting applications as electronic switches based on self-healing soft devices.

Exfoliated graphite (ExG) embedded in a polymeric matrix represents an accessible, cost-effective, and sustainable method for generating nanosized graphite-based polymer composites with multifunctional properties. This review article analyzes diverse methods currently used to exfoliate graphite into graphite nanoplatelets, few-layer graphene, and polymer-assisted graphene. It also explores engineered methods for small-scale pilot production of polymer nanocomposites. It highlights the chemistry involved during the graphite intercalation and exfoliation process, particularly emphasizing the interfacial interactions related to steric repulsion forces, van der Waals forces, hydrogen bonds, π-π stacking, and covalent bonds. These interactions promote the dispersion and stabilization of the graphite derivative structures in polymeric matrices. Finally, it compares the enhanced properties of nanocomposites, such as increased thermal and electrical conductivity and electromagnetic interference (EMI) shielding applications, with those of neat polymer materials.

Rapid self-healing materials are highly demanded to decrease polymer pollution and increase the material’s service life. In this work, we designed a self-healing thermo-responsive nanocomposite containing homogeneously dispersed indium tin oxide (ITO) nanocrystals (NCs). ITO NCs were used as an infrared photothermal source owing to their outstanding near-infrared plasmonic properties and visible transparency. As a polymer matrix, a furan grafted polyketone (PKFU) was prepared via Paal–Knorr functionalization and crosslinked with an aromatic bismaleimide via the Diels–Alder (DA) reaction. Nanocomposites containing the 0.4, 0.9, and 1.5 wt% of ITO NCs showed strong absorption between 1500 and 2250 nm and once exposed to a cheap IR lamp, they showed rapid heating up to temperatures >160 °C within 30 seconds, compared to around 60 °C for the bare polymer. The addition of ITO NCs did not affect the thermal behaviour of the matrix with the retro-Diels–Alder onset above 95 °C and the softening point at 50 °C, which effectively enabled the healing process. Remarkably, the nanocomposite with 0.9 wt% of ITO NCs showed the fastest healing rate: healing occurs after 1 second of IR irradiation, compared to the 50 seconds required for the bare thermoset matrix.

This work focuses on the design of an engineered thermoplastic polymer containing pyrrole units in the main chain and hydroxyl pendant groups (A-PPy-OH), which help in achieving nanocomposites containing well-distributed, exfoliated and undamaged MWCNTs. The thermal annealing at 100 °C of the pristine nanocomposite promotes the redistribution of the nanotubes in terms of a percolative network, thus converting the insulating material in a conducting soft matrix (60 μΩ m). This network remains unaltered after cooling to r.t. and successive heating cycles up to 100 °C thanks to the effective stabilization of MWCNTs provided by the functional polymer matrix. Notably, the resistivity–temperature profile is very reproducible and with a negative temperature coefficient of −0.002 K⁻¹, which suggests the potential application of the composite as a temperature sensor. Overall, the industrial scale by which A-PPy-OH can be produced offers a straightforward alternative for the scale-up production of suitable polymers to generate multifunctional nanocomposites.