Cross-linked and recyclable electroconductive carbonaceous nanocompounds and polymers capable of dispersing and stabilising them, method, derived materials and uses

#The present invention refers to cross-linked and recyclable nanocomposites that can be used as additive or matrix for the manufacture of materials, and that provide thermostability properties, thermoreversibility, thermoadhesiveness, heat conductivity, electroconductivity, self-repair, self-assembly, conversion of electricity to heat, or a combination thereof. Said nanocomposites can be obtained by an in situ method by thermal treatment, from raw carbonaceous materials (Pure and Applied Optics 40 (2) 149-159 (2007)), including char, pitch, activated carbon, pyrolytic carbon, coke, graphite, organic material combustion residues, or selected from other carbonaceous materials comprising conductive structures, including graphite, graphene, carbon nanotubes including multi-walled carbon nanotubes and single-walled carbon nanotubes, fullerenes, or a combination of the themselves or their derivatives, and a polymer capable of reversibly dispersing and stabilizing said components, where said polymer has a viscous or fluid behaviour below 200 °C, where said polymer is selected from a derivatized polymer with pendant groups that act as diene or dienophilic, preferably said derivatized polymer with pendant groups acting as diene or dienophilic is selected from p furan functionalized aliphatic olketones, furan functionalized polyesters, furan functionalized ethylene propylene gum, or a combination thereof. The invention also relates to materials derived from these nanocomposites that import their unique inherent properties to give them properties of thermostability, thermoreversibility, thermosetting, thermoconductivity, electroconductivity, self-repair, self-assembly, conversion of electricity into heat, or a combination thereof. The invention also refers to a method of obtaining said nanocomposites, and use of the nanocomposites as additive or thermosetting, thermoreversible, thermoadhesive, thermoconductive, electroconductive, self-repairing, heat-converting electricity, or a combination thereof, and use of derived materials in applications made of self-assembling, self-healing, heat-conducting, electro-conducting materials, electricity-heat converters, or a combination thereof.

#Composite materials containing graphene, carbon nanotubes, or nano-dispersed and interconnected fullerenes exhibit exceptional properties that can lead to advanced, next-generation materials. However, the high cost of producing graphene, carbon nanotubes and fullerenes greatly limits their adoption by the market. Therefore, methods have been sought to emulate the properties of said compounds from raw materials such as char, pitch, activated carbon, pyrolytic carbon, coke, graphite, combustion residues of organic material, or other mixtures of carbonaceous materials. For example, one of the strategies to obtain materials with the properties of graphene from graphite consists of the exfoliation of graphite in graphene by means of mechanical exfoliation by agitation and sonication assisted by organic solvents, surfactants or liquid ions. The exfoliation of graphite in graphene can also be carried out by thermal treatments, by means of conventional heating and microwave irradiation assisted by solvents and surfactants. Another form of exfoliation of graphite on graphene is through supercritical fluids with carbon monoxide or assisted with organic solvents such as dimethylformamide and N-methylpyrrolidone (Minzhen Cai., Et. al., Methods of graphite exfoliation. J. Mater. Chem., 22, 24992, (2012)). There have also been successful examples of exfoliation of carbon nanotube aggregates (Araya-Hermosilla, R., et. al., An Easy Synthetic Way to Exfoliate and Stabilize MWCNTs in a Thermoplastic Pyrrole-Containing Matrix Assisted by Hydrogen Bonds. RSC Adv. 2016, 6, 85829-85837).

#Composite materials containing graphene, carbon nanotubes, or fullerenes contain, in addition to carbonaceous structures, polymers that serve as a dispersing and structuring matrix for the material. Conductive polymer nanocomposites are an important class of materials used in a wide range of applications, including supercapacitors, solar cells, conductive adhesives, advanced electronic devices, among many others (Leng, J.; Kin-Tak Lau, A. Multifunctional Polymer Nanocomposites; Taylor and Francis Group: Boca Raton, FL, USA; London, UK; New York, NY, USA, 2011). For example, polymer nanocomposites with carbon nanotubes Cross-linked offer many superior properties compared to those based solely on thermoplastic polymers, such as mechanical strength, dimensional stability at elevated temperature, solvent resistance, and reliable electrical performance due to the conductive network of well-dispersed carbon nanotubes (Imtiaz, S.; Siddiq, M.; Kausar, A.; Muntha, ST; Ambreen, J.; Bibi, I. A Review Featuring Fabrication, Properties and Applications of Carbon Nanotubes (CNTs) Reinforced Polymer and Epoxy Nanocomposites. Chin. J. Polym. Sci. 2018, 36, 445-461).

#FIG. 1. Schematic representation of PK functionalized with furan (PK-Fu) or benzyl (PK-Bea) groups through the Paal-Knorr reaction.

#FIG. 2. Functionalization of MWCNT with (A) PK-Fu (diene) and (B) bis-maleimide (dienophile) by Diels-Alder reaction.

#FIG. 3. X-ray photoemission spectrum of the central level regions of CIs, NIs and Oís of MWCNTs functionalized with PK-Fu. Data and fit lines are displayed.

#The present invention refers to cross-linked and recyclable nanocomposites that can be used as additive or matrix for the manufacture of materials, and that provide properties of thermostability, thermoreversibility, thermoadhesiveness, thermoconductivity, electroconductivity, self-repair, self-assembly, conversion of electricity into heat, or a combination of them. Said nanocomposites can be obtained by an in situ method by thermal treatment, from raw carbonaceous materials (Pure and Applied Optics 40 (2) 149-159 (2007)), including char, pitch, activated carbon, pyrolytic carbon, coke, graphite, organic material combustion residues, or selected from other carbonaceous materials comprising conductive structures, including graphite, graphene, carbon nanotubes including multi-walled carbon nanotubes and single-walled carbon nanotubes, fullerenes, or a combination of the themselves or their derivatives, and a polymer capable of reversibly dispersing and stabilizing said components, where said polymer has a viscous or fluid behavior below 200 °C, where said polymer is selected from a derivatized polymer with pendant groups that act as diene or dienophilic, preferably said derivatized polymer with pendant groups acting as diene or dienophilic is selected from furan functionalized aliphatic polyketones, furan functionalized polyesters, ethylene gum with propylene functionalized with furan groups or a combination thereof. The invention also relates to materials derived from these nanocomposites that import their unique inherent properties to give them properties of thermostability, thermoreversibility, thermosetting, thermoconductivity, electroconductivity, self-repair, self-assembly, conversion of electricity into heat, or a combination thereof. The invention also relates to a method of obtaining said nanocomposites, and their use as an additive or matrix thermosetting, thermoreversible, thermoadhesive, thermoconductive, electroconductive, self-repairing, converting electricity into heat, or a combination thereof.

#In order to obtain viscosity and fluidity properties below 200 °C, said aliphatic polyketone is selected from low molecular weight polyketones, preferably with a carbon chain length greater than 50 carbons, preferably greater than 100 carbons, more preferably the carbon chain length is in the range of 100-500 carbons, even more preferably 120-200 carbons. Said aliphatic polyketone can also be selected from high molecular weight polyketones, preferably with molecular weights greater than 10,000 daltons, preferably greater than 50,000 daltons, even more preferably greater than 100,000 daltons, and even more preferably in the range of 50-500 thousand daltons, and even more preferably it is in the range between 100 to 200 thousand daltons. In these cases, the goal of viscosity and fluidity below 200 °C can be achieved by derivatization reactions with organic side groups, such as saturated and unsaturated alkyl groups, alcohols, amines, esters, ethers and polyethers, mercaptans, etc.

#The nanocomposites of the present invention are cross-linked, thermoset and recyclable, they are conductive, thermally reversible, and present possibilities of thermomechanical reprocessing and stable electrical response; in addition, they behave like a thermoplastic when heated or pressed. Preferably they comprise viscous and fluid polymers below 200 °C, derivatized with diene and dienophilic groups that have characteristics of formation of reversible, easily processable thermoset polymers, including polyketones derivatized with pendant chemical groups that act as diene or dienophiles, capable of producing Reversible Diels-Alder reactions. Results obtained demonstrate the successful chemical modification of polyketone with a variety of functional chemical groups. In particular, the derivatization of polyketones with furanyl groups leads to polymers with the desired characteristics to link reversibly electrically conductive carbonaceous structures (FIG. 1).