Synthesis of functionalized polymers by devulcanization of elastomer-containing waste

Description

technical field

[0001] The present invention relates to the field of waste treatment for elastomers of natural and / or synthetic origin. The invention specifically targets waste containing rubber, the majority of which consists of tire waste.

[0002] The present invention aims at the treatment of waste containing highly vulcanized elastomers, such as truck tire waste. Prior art

[0003] Prior art exists for the energy recovery of rubber waste. Energy recovery consists of incinerating rubber waste to produce energy. Energy recovery is extremely polluting.

[0004] The prior art of mechanically recovering rubber waste is known. This technique consists of grinding waste to produce granules that can be used as additives by cement plants or incorporated into certain materials.

[0005] The prior art also includes the chemical recovery of rubber waste. Chemical recovery encompasses pyrolysis and devulcanization. Pyrolysis involves decomposing rubber waste in the partial or complete presence of oxygen to obtain, among other things, pyrolytic oil. The pyrolysis of rubber waste is a very expensive process.

[0006] Devulcanization involves breaking the cross-linking nodes by causing the rupture of carbon-sulfur bonds and / or disulfide bridges, thereby partially or completely breaking the three-dimensional structure of the vulcanized rubber. Mechanical devulcanization, microwave devulcanization, and chemical devulcanization are known in the prior art.

[0007] Mechanical devulcanization is carried out by extrusion and causes a non-selective breaking of the disulfide bonds, the carbon-carbon bonds of the polymer chain are also broken.

[0008] Microwave devulcanization aims to break carbon-sulfur bonds or disulfide bridges by emitting specific microwaves. However, and especially in the presence of carbon black in the composition of rubber waste, as is the case with tire waste, this method causes a very significant temperature increase in the waste within seconds. This sudden temperature rise leads to the breaking of the carbon-carbon bonds in the polymer chain.

[0009] Finally, we know of the chemical devulcanization of rubber waste either by disulfide metathesis, or by breaking of disulfide bonds by means of a devulcanizing agent.

[0010] Metathesis has the major disadvantage of being a balanced reaction, preventing the achievement of high devulcanization rates.

[0011] Devulcanization by breaking disulfide bonds using a devulcanizing agent has the advantage of being energy-efficient. However, this process still has limitations related to the relatively low devulcanization rates achieved and its lack of selectivity. The main limitation of this technique lies in obtaining extremely low devulcanization rates when the rubbers to be devulcanized have high vulcanization rates.

[0012] Regarding chemical devulcanization, prior art documents include Rooj S., Maji PK, Basak GC, Bhowmick AK, *Journal of Polymers and the Environment*, 2011, vol. 19, pp. 382–390, and Zohuri G., Asadi S., Kariminejad M., Mortazavi SM., Chenar MP., Sabzekar M., *Polymer Degradation and Stability*, 2015, vol. 118, pp. 88–95. In addition, US4305850A and CH232893A disclose a process for treating an elastomer (rubber) with an organic peroxide for devulcanization / decomposition. None of the cited documents discloses the use of a peroxide according to formula 1 of the application. This formula explicitly excludes the use of benzoyl peroxide (where R = R' = H).

[0013] One aim of the invention is to overcome these drawbacks and in particular to propose a process for the synthesis of polymers by devulcanization of waste containing elastomers.

[0014] Another goal is to propose a process for synthesizing polymers by devulcanizing waste containing elastomers with a high devulcanization rate.

[0015] Another goal is to propose a process for the selective synthesis of polymers by devulcanization of waste containing elastomers, allowing control of the microstructure of the polymers obtained.

[0016] Another goal is to propose a polymer synthesis process by devulcanizing waste containing elastomers, enabling high devulcanization rates to be obtained from highly vulcanized rubber waste.

[0017] Another goal is to propose a polymer synthesis process by devulcanizing waste containing elastomers, enabling the synthesis of functionalized polymers. Presentation of the invention

[0018] To this end, according to a first aspect of the invention, a process for synthesizing polymers by devulcanization from waste containing elastomers is proposed. The process according to the invention comprises: a) bringing said waste containing elastomers into contact with a solvent in the presence of a devulcanizing agent, b) heating the mixture obtained in step a) at a temperature between 20°C and 250°C for a period of between 15 minutes and 24 hours. Thus, according to the first aspect of the invention, the devulcanizing agent, referred to as AD, is a radical initiator. For example, the devulcanizing agent is a devulcanizing agent for crosslinking nodes comprising a sulfur atom bonded to another sulfur atom or to a carbon atom. The radical initiator is capable of forming one or more radicals. Preferably, the devulcanizing agent is capable of forming radicals by homolysis. Even more preferably, the devulcanizing agent is a peroxide.

[0019] According to the first aspect of the invention, namely: The radical initiator is a compound of formula (1) in which R and R' are identical or different and each represent, independently of each other, a substituent exerting a mesomeric donor effect or a mesomeric attractor effect or an inductive donor effect or an inductive attractor effect, i.e. the concentration of devulcanizing agent, is such that the ratio between said concentration of devulcanizing agent, expressed as part percent of elastomer (phr), and a volume of solvent, expressed in ml, is: greater than 0.3 phr / ml of solvent or less than 0.2 phr / ml of solvent when the process is carried out under air, greater than 0.06 phr / ml of solvent when the process is carried out under an inert atmosphere.

[0020] According to the invention, R and R' exerting a donating mesomeric effect, an withdrawing mesomeric effect, a donating inductive effect, or an withdrawing inductive effect are chosen independently of each other from the group comprising hydrogen (-H), halogen atoms chosen from iodine, bromine, fluorine, and chlorine, the (C1-18)alkyl group, primary (-NH2), secondary (-NHRa1, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings), or tertiary (-NRa1, Ra2, where Ra1 and Ra2, identical or different, may each independently be a (C1-C5)alkyl group or an aromatic ring), hydroxyl (-OH), alkoxides (or a salt) (Ra1-O-), Ra1 being chosen from the (C1 -C5)alkyls and aromatic rings), (C1-C5)alkoxy groups, a thiol (-SH), thioethers (-SRa1, Ra1 being chosen from the (C1-C5)alkyl groups and aromatic rings), a thiolate (or a salt) (Ra1-S-<),Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings), an aromatic ring, a conjugate base of a carboxylic acid (-COO-), a carboxylic group (-COOH), esters (-CO2Ra1, Ra1 being chosen from (C1-C5)alkyl groups and heterocycles), an aldehyde group (-CHO), a carbonyl group (-COR), a nitro group (-NO2), a nitrile group (-CN), a sulfonyl group (-SO2-), a sulfonate group (salt or acid)(-SO3), a sulfone (-SO2R), a phosphate group -O-PO(ORa1)(ORa2) where Ra1 and Ra2, identical or different, can each be independently of each other, a hydrogen group or (C1-C5)alkyl or an aromatic ring), a primary amide group (-CONH 2 ), secondary (-CONHRa 1 , Ra 1 being chosen from the (C 1 -C 5 )alkyl groups and aromatic rings ) or tertiary (-CONRa 1 Ra 2 ,Ra1 and Ra2, whether identical or different, can each independently be a (C1-C5)alkyl group or an aromatic ring.

[0021] The term (C1-C18)alkyl means any linear or branched carbon chain having from 1 to 18 carbon atoms and includes all alkyl groups having 1 to 18 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl groups.Preferably, the (C1-C18)alkyl group comprises chains of 1 to 8 carbon atoms or (C1-C5)alkyl groups, in particular the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl, hexyl, heptyl, octyl groups, preferably also chains of 1 to 5 carbon atoms or (C1-C5)alkyl groups such as the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl groups and more preferably chains of 1 to 3 carbon atoms or (C1-C3)alkyl groups, in particular the methyl, ethyl, n-propyl and isopropyl groups.

[0022] The term (C1-C5)alkyl means any linear or branched carbon chain having from 1 to 5 carbon atoms and includes all alkyl groups having 1, 2, 3, 4 or 5 carbon atoms, in particular the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl and isopentyl groups.

[0023] The term (C1-C5)alkoxy is an O-(C1-C5)alkyl group where the (C1-C5)alkyl group is as defined previously. Examples include the methoxy, ethoxy, butoxy, and pentoxy groups.

[0024] The term aromatic ring includes aryl groups, notably phenyl, benzyl, naphthyl, biphenyl, and tetrahydronaphthyl groups, as well as heterocycles, that is, rings which, in addition to carbon atoms, also include heteroatoms such as nitrogen, oxygen, and sulfur. Examples of heterocycles include benzimidazolyls, furyls, imidazolyls, piperazinyls, piperidinyls, pyranyls, pyrazinyls, pyroazolidinyls, pyrazolinyls, pyridazinyls, pyridooxazoles, and pyridoimidazoles.

[0025] Preferably, R and R' each represent, independently of each other, a hydrogen atom, a fluorine atom, a methoxy group or an acetoxy group.

[0026] Even more preferably, R and R' are identical and each represent a fluorine atom, a methoxy group or an acetoxy group.

[0027] When the radical initiator is a compound of formula (1), the polymers obtained by implementing the process are functionalized polymers.

[0028] In an advantageous embodiment of the first aspect of the invention: the radical initiator is a compound of formula (1), and the concentration of devulcanizing agent is such that the ratio between said concentration of devulcanizing agent, expressed in part percent of elastomer (phr), and a volume of solvent, expressed in ml, is: greater than 0.3 phr / ml of solvent or less than 0.2 phr / ml of solvent when the process is carried out under air, greater than 0.06 phr / ml of solvent when the process is carried out under an inert atmosphere.

[0029] Advantageously, R, R', or both are not hydrogen atoms. In other words, either R and R' are not hydrogen atoms, or R is not hydrogen atoms, or R' is not hydrogen atoms. In other words, R and R' are not simultaneously hydrogen atoms.

[0030] The process according to the invention makes it possible to obtain polymers. Preferably, the process according to the invention makes it possible to obtain polymers, in particular elastomers.

[0031] According to the invention, the polymers obtained are functionalized polymers of formula 2 and / or 2' in which R and R' are identical or different and are as defined previously, and x is an integer between 0 and 6 and preferably equal to 0, 1, 2, 3, 4, 5 or 6, and n is an integer between 6 and 600. The number n represents the number of motifs, each comprising a functional group, having been introduced along the polymer chain during devulcanization.

[0032] Advantageously, R and R' are different from a hydrogen atom.

[0033] Unlike prior art processes in which the functional group(s) are introduced only at the end of the polymer chain, the functional group(s) are introduced within the polymer chain. Thus, the process according to the invention makes it possible to introduce the functional group(s) within the polymer chain, thereby obtaining functionalized polymers of formula 2 and / or 2'.

[0034] The process according to the invention is based on the synthesis of polymers by devulcanizing the crosslinking nodes present in the waste from which the process is carried out. A crosslinking node comprises at least one sulfur atom bonded to another sulfur atom or to a carbon atom. Such crosslinking nodes are present, in particular, in elastomers. Therefore, according to the invention, waste containing elastomers is understood to mean waste containing sufficient elastomers so that, after implementation of the process, the quantity of polymers synthesized is sufficient to be recovered. A person skilled in the art, based on their general knowledge, will be able to determine, from the elastomer content of the waste to be treated, whether the synthesis of polymers by implementing the process according to the invention is appropriate.

[0035] According to the invention, waste comprising at least 10%, preferably at least 30%, by mass of elastomers relative to the total mass of waste has a sufficient concentration for polymer synthesis by devulcanization according to the invention to be carried out from said waste. According to the invention, waste containing elastomers may include: polyisoprene and / or polybutadiene, and / or butadiene-acrylonitrile, (Nitrile Butadiene Rubber or NBR), and / or styrene-butadiene, (Styrene-Butadiene Rubber SBR), and / or ethylene-propylene diene monomers, (Ethylene Propylene Diene Monomer or EPDM), and / or may be natural rubber waste (Natural Rubber or NR), and / or butyl rubber.

[0036] Preferably, waste containing elastomers can be truck tire waste, referred to as highly vulcanized elastomeric waste. Highly vulcanized is understood to mean elastomers having a crosslinking density greater than 10⁻⁴ mol / ml, preferably greater than 10⁻³ mol / ml.

[0037] As a non-limiting example, if the waste is pneumatic waste, it contains, once the metallic parts have been removed, essentially rubber, called gum, and carbon black, called filler.

[0038] According to a particular embodiment of the invention, the pneumatic waste used is cut tire, shredded tire, powder or granules, preferably powder or granules.

[0039] Preferably, when the process is carried out in air, the concentration of the devulcanizing agent is: between 0.3phr / ml of solvent and the concentration value, in phr / ml of solvent, for which the solubility limit of the AD in the solvent is reached, or less than 0.2phr / ml of solvent. A person skilled in the art, using their general knowledge and the instruction in this document, will be able to determine the maximum concentration of AD that is possible or appropriate to use. Similarly, when the AD concentration is less than 0.2 ppm / ml of solvent, a person skilled in the art, using their general knowledge and the instruction in this document, will be able to determine the minimum AD concentration that is possible or appropriate to use.

[0040] Preferably, when the process is carried out in air, the concentration of AD is: between 0.3phr / ml and 8phr / ml of solvent, or less than 0.2phr / ml of solvent.

[0041] Preferably, when the process is carried out in air, the concentration of AD is: between 0.3phr / ml and 0.6phr / ml of solvent, or less than 0.2phr / ml of solvent.

[0042] Preferably, when the process is carried out under argon, the concentration of AD is between 0.06phr / ml of solvent and the value of its concentration, in phr / ml of solvent, for which the solubility limit of AD in the solvent is reached.

[0043] Preferably, when the process is carried out under an inert atmosphere, the concentration of AD is between 0.06phr / ml and 8phr / ml of solvent.

[0044] Preferably, when the process is carried out under an inert atmosphere, the concentration of AD is between 0.06phr / ml and 0.6phr / ml of solvent.

[0045] According to the invention, an inert atmosphere is understood to be an atmosphere that does not react under the conditions of implementation of the process. A non-limiting example is an atmosphere composed mainly of nitrogen and / or noble gases such as argon. Preferably, the atmosphere is composed of nitrogen and / or noble gases.

[0046] Preferably, step b of the process is carried out at a mixture temperature between 20°C and 150°C, more preferably between 40°C and 120°C, and even more preferably between 60°C and 100°C. Most preferably, the process is carried out at a temperature of 80°C.

[0047] Preferably, the heating time is between 1 hour and 8 hours, preferably between 1 and 6 hours.

[0048] Preferably, R and R' are chosen from groups comprising one or more atoms of carbon and / or oxygen and / or nitrogen and / or phosphorus and / or sulfur and / or halogen.

[0049] The polymers synthesized by the process according to the invention can be composed of a mixture comprising polymers and oligomers. Preferably, the synthesized polymers are oligomers. According to the invention, oligomers are considered to be a chain of monomers having a molar mass of less than 2000 g / mol.

[0050] According to the invention, the solvent may be an organic solvent, an ionic liquid, a deep eutectic solvent, or a mixture thereof. For example, the ionic liquid may be selected from phosphoniums, imadazoliums, or pyridiniums. The ionic liquids according to the invention consist of an anion and a cation and may have the following general formula: , in whichA n-< is an anion selected from the group comprising PF6-< , NO3-< , F, Cl-< , Br-< ​​, I-< , R 9< SO 3-< , R 9< SO3-< , R 9< CO 3-< , CF 3 SO 3-< , BF 4-< , B(R 9< ) 4-< , CF 3 CO 2-< , R 9< P0 2-< , (CF 3 SO 2 )N-< , CH 3 SO 3-< , (C 12 H 25 )C 6 H 4 SO 3-< , R 9< CO 2-< ; R 9< being chosen from the group comprising substituted or unsubstituted alkyl, substituted or unsubstituted aryl, and alkoxy; with n being equal to 1, 2 or 3 depending on the negative charge of the previously mentioned anion and (1 / n) being equal to 1 if the anion has one negative charge, 1 / 2 if the anion has two negative charges and 1 / 3 if the anion has three negative charges, X is a nitrogen, phosphorus or sulfur atom with the condition that when X is a sulfur atom, at least one of the groups R1<, R2<, R3<, R4< is zero, R1<, R2<, R3<, R4<, R5<, R6<, R7< and R8< are identical or different, each being chosen from a group including hydrogen, halogen, alkoxy,Substituted or unsubstituted alkyl, substituted or unsubstituted aryl, and R1< -R2< , R2< -R3< , R3< -R4< , R4< -R5< , R5< -R6< , R6< -R7< , R7< -R5< or R8< -R1< can represent a ring with 5, 6 or 7 carbon atoms, Z1< , Z2< , Z3< are identical or different and are chosen from a group comprising one carbon atom and one nitrogen atom, provided that at least one of the atoms Z1< , Z2< and Z3< represents a nitrogen atom and when one of the atoms Z1< , Z2< and Z3< is a nitrogen atom, the group R1< , R2< , R 3< corresponding is zero. ,

[0051] These ionic liquids are described on pages 9 to 15 of patent application FR 3014104.

[0052] The deep eutectic solvents according to the invention can be selected from: mixtures of quaternary ammonium salt and metal chloride, by way of non-limiting example such a mixture may be a mixture of 1-ethyl-3-methylimidazolium and aluminium chloride (AlCl3), mixtures of quaternary ammonium salt and hydrated metal chloride, mixtures of quaternary ammonium salt and hydrogen bond donor, by way of non-limiting example the hydrogen bond donor may be urea or a urea derivative, mixtures of hydrated metal chloride and hydrogen bond donor, by way of non-limiting example the hydrogen bond donor may be urea or a urea derivative and by way of non-limiting example such a mixture may be a mixture of aluminium chloride (AlCl3) and urea.

[0053] Preferably, the deep eutectic solvent can be a mixture of choline chloride and urea. Even more preferably, the deep eutectic solvent can be a mixture of 1 mol / L choline chloride and 2 mol / L urea.

[0054] Deep eutectic solvents may include, in part or in whole, natural products from among a mixture of aconitic acid and choline chloride, a mixture of malic acid and glucose, a mixture of malic acid and fructose, a mixture of malic acid and sucrose, a mixture of citric acid and sucrose, a mixture of maleic acid and sucrose, a mixture of glucose and fructose, a mixture of fructose and sucrose, a mixture of glucose and sucrose, a mixture of maleic acid and glucose, a mixture of citric acid and glucose.

[0055] The solvent can be a mixture of solvents. Preferably, the solvent can be a mixture of an organic solvent and an ionic liquid or a mixture of an organic solvent and a deep eutectic.

[0056] The organic solvent is chosen from among nonpolar aromatic or aliphatic solvents. Preferably, the organic solvent is xylene.

[0057] The heating time of the mixture can be between 1 and 12 hours when the process is carried out under an inert atmosphere.

[0058] Preferably, the heating time of the mixture can be between 2 hours and 4 hours when the process is carried out under an inert atmosphere.

[0059] Preferably, the heating time of the mixture is 3 hours when the process is carried out under an inert atmosphere.

[0060] The heating time of the mixture can be between 1 and 12 hours when the process is carried out under air.

[0061] Preferably, the heating time of the mixture can be between 3 and 5 hours when the process is carried out under air.

[0062] In a preferred manner, the heating time of the mixture is 4 hours when the process is carried out under air.

[0063] In a preferred manner, when the process is carried out under air, the concentration of AD is less than 0.2phr / ml of solvent.

[0064] The process may include, prior to step a), an activation step for waste containing elastomers, by freeze-drying, swelling, or treatment with supercritical CO2. Swelling may be carried out in an organic solvent, an ionic liquid, or a deep eutectic solvent. Freeze-drying may be carried out directly in water, after which the water is removed by sublimation. Freeze-drying may be carried out in a solvent other than water; in this case, a solvent exchange step from the solvent, which is other than water, to water is carried out prior to the sublimation step. For treatment with supercritical CO2, the waste is swollen in fluid CO2, after which the CO2 is removed by evaporation. A person skilled in the art, using their general knowledge, is capable of implementing these different waste activation techniques.

[0065] The swelling activation step can be carried out in the same or a different solvent as that used during the devulcanization process.

[0066] Preferably, the activation step by swelling can be carried out: in an organic solvent with a dipole moment between 0.5 and 2.5 Debye, or in an ionic liquid, a deep eutectic solvent or by treatment with supercritical carbon dioxide.

[0067] Preferably, the organic solvent with a dipole moment between 0.5 and 2.5 Debye is an aprotic solvent.

[0068] Preferably, the organic solvent with a dipole moment between 0.5 and 2.5 Debye is dichloromethane (DCM) or tetrahydrofuran (THF).

[0069] When the swelling activation step is carried out in an organic solvent with a dipole moment between 0.5 and 2.5 Debye, the swelling step is carried out outside the mixture, prior to devulcanization.

[0070] The process may also include, subsequent to step b), a step of separating the resulting polymers. This step can be carried out by any technique known to those skilled in the art, for example, by filtration, centrifugation, or precipitation. The liquid phase, which contains the polymers, is recovered. In the case of tire waste, the solid phase, which contains carbon black, can be reused in a new formulation.

[0071] When the polymers synthesized by the devulcanization process according to the invention comprise a mixture of polymers and oligomers, the separation step may include a step: recovery of oligomers solubilized in a solvent, for example a polar solvent, in which the polymers are not soluble, and / or metathesis generating the breaking of the carbon-carbon double bonds of the polymers not soluble in the solvent used to solubilize the oligomers so as to form oligomers soluble in said solvent.

[0072] The devulcanization reaction and the rubber waste activation step can be implemented continuously.

[0073] Preferably, when the devulcanization reaction and the activation step of waste containing elastomers are implemented continuously, they are implemented concurrently.

[0074] Preferably, when the devulcanization reaction and the activation step of waste containing elastomers are implemented continuously, they are implemented in the mixture.

[0075] Preferably, when the devulcanization reaction and the activation step of waste containing elastomers are implemented continuously, the solvent of the mixture is an ionic liquid or a deep eutectic.

[0076] When the devulcanization reaction and the activation step of waste containing elastomers are implemented continuously in an ionic liquid or a deep eutectic, the polymers obtained precipitate directly into the mixture.

[0077] According to the invention, the process according to the first aspect of the invention is a recycling process enabling the recovery of waste comprising elastomers.

[0078] According to a second aspect of the invention, a functionalized elastomer is proposed, according to formula 3 and / or 3'. in which x is an integer between 0 and 6, preferably equal to 0, 1, 2, 3, 4, 5, or 6; n represents the number of motifs, each comprising a functional group introduced along the polymer chain during devulcanization, and is an integer between 6 and 600; m represents the number of monomers in the polymer and is an integer between 6 and 600; Y is a hydrogen atom or a methyl group; and R and R', identical or different for each motif, are chosen from the group comprising hydrogen (-H), halogen atoms chosen from iodine, bromine, fluorine, and chlorine, the (C1-18)alkyl group, primary (-NH2), secondary (-NHRa1, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings), or tertiary amines. (-NRa 1 Ra 2 , where Ra 1 and Ra2 identical or different can each independently be a (C 1 -C 5 )alkyl group or an aromatic ring), the hydroxyl (-OH),alkoxides (or a salt) (Ra1-O-, Ra1 being selected from (C1-C5)alkyl groups and aromatic rings), (C1-C5)alkoxy groups, a thiol (-SH), thioethers (-SRa1, Ra1 being selected from (C1-C5)alkyl groups and aromatic rings), a thiolate (or a salt) (Ra1-S-, Ra1 being selected from (C1-C5)alkyl groups and aromatic rings), an aromatic ring, a conjugate base of a carboxylic acid (-COO-), a carboxylic group (-COOH), esters (-CO2Ra1, Ra1 being selected from (C1-C5)alkyl groups and heterocycles), an aldehyde group (-CHO), a carbonyl group (-COR), a nitro group (-NO2), a nitrile group (-CN), a sulfonyl group (-SO2-), a sulfonate group (salt or acid)(-SO3), a sulfone (-SO2R), a phosphate group -O-PO(ORa1)(ORa2) where Ra1 and Ra2, identical or different, can each independently be a hydrogen group or (C1-C5)alkyl or an aromatic ring),a primary amide group (-CONH2), secondary (-CONHRa1, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings) or tertiary (-CONRa1Ra2, Ra1 and Ra2 being identical or different, each can independently be a (C1-C5)alkyl group or an aromatic ring.

[0079] The term (C1-C18)alkyl means any linear or branched carbon chain having from 1 to 18 carbon atoms and includes all alkyl groups having 1 to 18 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl groups.Preferably, the (C1-C18)alkyl group comprises chains of 1 to 8 carbon atoms or (C1-C5)alkyl groups, in particular the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl, hexyl, heptyl, octyl groups, preferably also chains of 1 to 5 carbon atoms or (C1-C5)alkyl groups such as the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl groups and more preferably chains of 1 to 3 carbon atoms or (C1-C3)alkyl groups, in particular the methyl, ethyl, n-propyl and isopropyl groups.

[0080] The term (C1-C5)alkyl means any linear or branched carbon chain having from 1 to 5 carbon atoms and includes all alkyl groups having 1, 2, 3, 4 or 5 carbon atoms, in particular the methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl and isopentyl groups.

[0081] The term (C1-C5)alkoxy is an O-(C1-C5)alkyl group where the (C1-C5)alkyl group is as defined previously. Examples include the methoxy, ethoxy, butoxy, and pentoxy groups.

[0082] Preferably, R or R' each independently represents a hydrogen atom, a fluorine atom, a methoxy group, or an acetoxy group.

[0083] According to the invention, R and R' can be different from a hydrogen atom.

[0084] Even more preferably, R and R' represent a fluorine atom, a methoxy group, or an acetoxy group.

[0085] As described previously, unlike prior art processes in which the functional group(s) are introduced only at the end of the polymer chain, the functional group(s) are introduced within the polymer chain. Thus, the process according to the invention makes it possible to introduce the functional group(s) within the polymer chain, thereby obtaining functionalized polymers of formula 3 and / or 3'.

[0086] Formula 4 illustrates the general chemical structure of an elastomer.

[0087] According to a third aspect of the invention, it is proposed to use functionalized elastomers according to the second aspect of the invention as materials.

[0088] Preferably, the use of functionalized elastomers according to the second aspect of the invention is proposed as elastomeric materials, thermoplastic elastomers or elastomers for biomedical applications.

[0089] According to a fourth aspect of the invention, polymer compositions are proposed that can be obtained by the process according to the first or second aspect of the invention. The process according to the invention makes it possible to obtain polymer compositions. These polymer compositions may consist of oligomers or a mixture comprising polymers and oligomers. The polymer composition depends on the waste subjected to the devulcanization process according to the invention. The polymer composition includes elastomers when the waste contains elastomers.

[0090] According to a fifth aspect of the invention, it is proposed to use the polymer compositions obtained according to the fourth aspect of the invention as an additive to fresh or new elastomer mixtures, as additives or reagents of the surfactant, crosslinking or chain extender type.

[0091] It is also proposed that the polymer compositions obtained according to the fourth aspect of the invention be used as materials, in particular as thermoplastic elastomers or elastomers in the biomedical field. Description of the implementation methods

[0092] According to the embodiments presented, the devulcanization process is carried out using granules or powders of truck tire waste. The overall reaction of the chemical devulcanization process by breaking disulfide bonds using a devulcanizing agent is shown in reaction schemes 1 and 1' below.

[0093] This devulcanization process thus constitutes a route for synthesizing polymers from tire waste. The type of polymer synthesized, in terms of chain length, is primarily governed by the degree of polymerization of the elastomers contained in the waste from which the process is carried out. According to the embodiments described, the waste containing elastomers from which the process is carried out originates from truck tire waste. Depending on the parameters used to implement the process, the synthesis results in oligomers or a mixture comprising polymers and oligomers.The polymers obtained according to the reaction scheme 1 comprise a number, denoted n, of motifs, each comprising a functional group having been introduced along the polymer chain during devulcanization, which is between 6 and 600, a number of sulfur atoms, denoted x, linking the functional group to the polymer chain which is between 0 and 6, and a number, denoted m, of monomers which comprise the polymer which is between 6 and 600.

[0094] Truck tire waste is known to be highly vulcanized. The devulcanizing agent is introduced at a rate of 6% by mass relative to the rubber waste. Those skilled in the art refer to this ratio as "phr," meaning 6 parts of devulcanizing agent to 100 parts of rubber waste by mass, "phr" standing for "per hundred rubber." The initial waste mass, when implementing each of the presented embodiments, is 300 mg.

[0095] According to the invention, once the synthesis process is complete, an additional step is carried out to recover the synthesized polymers: this involves treating the devulcanized waste with acetone using a Soxhlet apparatus for 24 hours to recover the functionalized polymers. When the synthesized polymers are in suspension and / or solvated, those skilled in the art will be able to select the most suitable chemical separation or extraction process for their recovery.

[0096] The devulcanization rate, denoted TDV hereafter, obtained after implementation of the process, is determined by Flory's principle through the variation of the crosslinking density according to the method described by Paul J. Flory and John Rehner, *The Journal of Chemical Physics*, 1943, vol. 11, p. 521. It thus allows for the specific measurement of disulfide bridge and carbon-sulfur bond breaks. The TDV value therefore allows for the specific evaluation of the efficiency of the devulcanization reaction. In state-of-the-art documentation, TDV is generally determined from sol-gel measurements, usually using a Soxhlet extraction method, and specifically from the soluble fraction of the devulcanized polymer. The determined soluble fraction includes the disulfide bridge and carbon-sulfur bond breaks, as well as the carbon-carbon bond breaks of the polymer chain.

[0097] Based on the observation that rubber is primarily composed of polyisoprene and that carbon-carbon double bonds are also susceptible to free radicals, the inventors deduced that the main source of depolymerization is that generated by the reaction of DA with the carbon-carbon double bonds of polyisoprene. Therefore, in order to accurately assess the selectivity of the process according to the invention, the degree of functionalization, denoted TDF hereafter, of the polyisoprene contained in the tire waste was studied in parallel under conditions identical to those used during the implementation of the process. The polyisoprene chosen to determine the TDF exhibits a degree of polymerization equivalent to that of the truck tire waste used. The TDF value will thus allow for a precise evaluation of the specificity of the devulcanization reaction with respect to disulfide bridges and carbon-sulfur bonds.A process that yields a TDF of less than 30% will be considered to have acceptable selectivity. The overall reaction for the depolymerization of polyisoprene by reaction of the devulcanizing agent on the carbon-carbon double bonds of polyisoprene or polybutadiene is shown in reaction scheme 2 below. The overall depolymerization reaction of polyisoprene by reaction of the devulcanizing agent on the carbon-carbon double bonds of polyisoprene or polybutadiene can be completed by the reaction scheme 3 below.

[0098] According to a first embodiment, the oligomer synthesis process by devulcanization is carried out under air and the AD is benzoyl peroxide of formula 1a, which corresponds to the compound of formula 1 in which R and R' are hydrogen atoms,

[0099] The solvent used is xylene.

[0100] Table 1 illustrates the effect of temperature on the process according to the first embodiment. It can be seen that a temperature change from 80°C to 100°C results in a doubling of the TDV but a twelvefold increase in the TDF. This demonstrates that the depolymerization reaction is significant above 80°C. Table 1 Volume of xylene (ml) Time (hours) Temperature (°C) V TDF 25 4 80 31,5% 7% 25 4 100 69,3% 83%

[0101] Table 2 illustrates the effect of time on the process according to the first embodiment. Table 2 shows that the TDV increases to a maximum at a reaction time of 4 hours and then decreases slowly. The TDF, on the other hand, is relatively stable and low. It increases from 5% for reaction times of two and three hours to 7% for reaction times of four and five hours. Table 2 Volume of xylene (ml) Time (hours) Temperature (°C) V TDF 25 2 80 17,4% 5% 25 3 80 26% 5% 25 4 80 31,5% 7% 25 5 80 30,5% 7%

[0102] Table 3 illustrates the effect of AD concentration on the process according to the first embodiment. For a concentration of 0.24 phr per milliliter of solvent, i.e., 6% by mass of AD in a solvent volume of 25 ml, the TDV is relatively low and the TDF is 5%. For an AD concentration of 0.6 phr / ml of solvent, i.e., 6% by mass of AD in a solvent volume of 10 ml (considered a high concentration), the TDV is 61.3% and the TDF is 82%. For an AD concentration of 0.06 phr / ml of solvent, i.e., 6% by mass of AD in a solvent volume of 100 ml (considered a low concentration), the TDV is 61.2% and the TDF is 18%. Surprisingly, for the same duration of process implementation, the TDV obtained for a high concentration of AD is similar to that obtained for a low concentration of AD.The high TDF value observed when implementing the process with a high AD concentration confirms the presence of a secondary depolymerization reaction. It is worth noting that even though selectivity is low when using high AD concentrations, the TDV obtained for highly vulcanized waste such as truck tire waste, with a crosslinking density of 13.5 x 10⁻⁴ mol / ml, is at least equal to, or even greater than, that obtained for rubbers with significantly lower crosslinking densities, typically 2.6 x 10⁻⁴ mol / ml. It is observed that for low AD concentrations, the process yields good TDV values ​​and exhibits very good selectivity, with a TDF of 18%. Table 3 Volume of xylene (ml) Time (hours) Temperature (°C) V TDF 25 4 80 31,5% 5% 10 4 80 61,3% 82% 100 4 80 61,2% 18%

[0103] According to a second embodiment, the process is carried out under an inert atmosphere, under argon, the active ingredient is benzoyl peroxide of formula 1a, and the solvent used is xylene.

[0104] Table 4 illustrates the effect of the inert atmosphere on the TDV (Total Devulcanization Volume) according to the second embodiment. The TDV is doubled compared to the process carried out under the same conditions in air. Conversely, the TDF (Total Devulcanization Factor) is also doubled but remains low. Thus, when optimal selectivity is required, the process in air is preferable, while when optimal devulcanization efficiency is required, the process in argon is preferable. Table 4 Atmosphere Volume of xylene (ml) Time (hours) Temperature (°C) V TDF Under air 25 4 80 31,5% 5% Under argon 25 4 80 67,3% 14%

[0105] Table 5 illustrates the effect of time on the process according to the second embodiment. Table 5 shows that the TDV increases to a maximum at a reaction time of 3 hours and then decreases rapidly. Conversely, the TDF increases with time. It rises from 10% for reaction times of two and three hours to 14% and then 16% for reaction times of four and five hours. Table 5 Volume of xylene (ml) Time (hours) Temperature (°C) V TDF 25 2 80 60% 10% 25 3 80 70% 10% 25 4 80 67,3% 14% 25 5 80 55% 16%

[0106] Table 6 illustrates the effect of AD concentration on the process according to the second embodiment. It can be seen that a decrease in AD concentration leads to a decrease in TDV and an increase in TDF. Also, unlike when the process is carried out under air, AD concentration values ​​above 0.06 phr / ml of solvent are preferred when the process is carried out under argon. This indicates that when the process is carried out under argon, in addition to the devulcanization and radical depolymerization reactions, an additional reaction occurs. This could, for example, be the crosslinking of sulfur radicals onto disulfide bridges and / or double bonds of the polymer chain.

[0107] It is also noted that the implementation of the process according to the second embodiment for AD concentration values ​​greater than 0.06phr / ml of solvent results in TDV and TDF values ​​that are equivalent to, or even slightly better than, those obtained when the process is implemented according to the first embodiment for AD concentration values ​​less than 0.2phr / ml of solvent. Table 6 Atmosphere Volume of xylene (ml) Time (hours) Temperature (°C) V TDF Under argon 25 4 80 67,3% 14% Under argon 100 4 80 59,3% 20% Under air 100 4 80 61,2% 18%

[0108] According to a particular embodiment of the process according to the invention, an activation step of the pneumatic waste granules is implemented prior to the devulcanization reaction.

[0109] According to one variant, the activation process includes a swelling step for the granules. Table 7 illustrates the influence of the solvent type on the granule swelling rate and the proportion of granules solubilized by the solvent. This swelling step involves introducing a given quantity of tire waste granules into a solvent for a specific time and recovering the portion of tire waste that has been solubilized. Each experiment was performed three times, and the calculated average is shown in Table 7. Table 7 shows that polar solvents, such as acetone (dipole moment µ = 2.86 Debye), are ineffective; the solubilized portion of the waste is very small, and the swelling rate is also very low. Nonpolar solvents, such as pentane (dipole moment µ = 0.2 D), are also ineffective.In contrast, the less polar solvents dichloromethane (DCM) (dipole moment µ=1.55D) and tetrahydrofuran (THF) (dipole moment µ=1.75D) show very good efficiency in solubilizing and swelling waste. This is particularly true when the experiment is performed using a Soxhlet extractor. Generally, a nonpolar solvent is considered to have a dipole moment less than 0.5D, and a polar solvent is considered to have a dipole moment greater than 2D or even 2.5D. Regarding the protic or aprotic nature of the solvent, it would appear that protic solvents exhibit the lowest efficiency. Indeed, when comparing ethanol (µ=1.74D), which has a dipole moment equal to that of THF and lower than that of acetone, it generates the lowest rate of swelling and the lowest solubilization of waste. Table 7 Solvent Time Terms Swelling rate Soluble part DCM 2h30 20ml 128% 6,4% DCM 2h30 Soxhlet 131% 8,4% DCM 24h 20ml 131% 9,8% THF 24h 20ml 126% 10,7% Acetone 2h30 20ml 12% 4,9% Ethanol 2h30 20ml 5% 2,3% Pentane 2h30 20ml 49% 7,7%

[0110] According to a second variant, the activation includes a freeze-drying step for the aggregates. The aggregates are swollen in DCM for 24 hours according to the process described in the first variant. Then, a solvent exchange of DCM-ethanol and then ethanol-water is carried out. The water-swollen aggregates are then frozen and freeze-dried for 48 hours.

[0111] Table 8 illustrates the effect of freeze-drying activation on the devulcanization of tire waste granules.

[0112] When the process is carried out in air using freeze-dried aggregates, the TDV is significantly higher than that obtained with unactivated aggregates. The TDF remains unchanged and low.

[0113] When the process is carried out under argon using freeze-dried granules, the TDV decreases significantly while the TDF remains constant. This indicates that the radical crosslinking that occurs during the argon-assisted process is exacerbated when the tire waste is freeze-dried. Furthermore, when the AD concentration decreases from 0.24 phr / ml of solvent to 0.06 phr / ml of solvent, the TDV decreases and the TDF increases. This further confirms the results above and those presented in Table 6, which show that radical crosslinking is amplified when the AD concentration decreases. Table 8 Type of waste Atmosphere Volume of xylene (ml) Time (hours) Temperature (°C) V TDF Aggregates Under air 25 4 80 31,5% 7% Freeze-dried granules Under air 25 4 80 53,1% 7% Aggregates Under argon 25 4 80 67,3% 14% Freeze-dried granules Under argon 25 4 80 55,8% 14% Freeze-dried granules Under argon 100 4 80 48% 20% Aggregates Under argon 100 4 80 59,3% 20%

[0114] According to a third variant, the activation includes a step of swelling the granules in an ionic liquid, trihexyltetradecylphosphonium chloride, known under the trade name "Cyphos 101" for 12 hours.

[0115] Table 9 illustrates the effect of implementing the process under air using granules that have undergone a swelling step in the ionic liquid. Compared to the TDV and TDF obtained without activation, a twofold increase in TDV and a significant increase in TDF are observed. Compared to the TDV and TDF obtained with freeze-drying activation, a substantial increase in TDV and a significant increase in TDF are observed. Table 9 Type of waste Volume of xylene (ml) Time (hours) Temperature (°C) V TDF Swollen granules in ionic liquid 25 4 80 55,8% 30% Aggregates 25 4 80 31,5% 7% Freeze-dried granules 25 4 80 53,1% 7%

[0116] According to a fourth variant, the activation includes a swelling step of the granules by treatment with supercritical CO₂ (ScCO₂). The activation step consists of treating the granules by swelling in ethanol or acetone, followed by solvent exchange between the ethanol or acetone and the ScCO₂ in a dehydrator. The results of the polymer synthesis by devulcanization carried out using ScCO₂-swollen granules are presented in Table 10. Table 10 Type of waste Volume of xylene (ml) Time (hours) Temperature (°C) V TDF Granules swollen by treatment with ScCO2 25 4 80 27% 7%

[0117] According to another embodiment of the process according to the invention, the devulcanizing agent used corresponds to formula 1 in which R and R' differ by one hydrogen atom. These devulcanizing agents are therefore derivatives of benzoyl peroxide (BPO). The use of such derivatives makes it possible to synthesize, by devulcanization of rubber waste, oligomers functionalized according to formula 3 and / or 3'. In addition to the fact that the synthesized oligomers originate from rubber waste, their functionalization constitutes a further advantage for their subsequent use. Indeed, since the functional group can include a wide choice of R, R' substituents as proposed according to the invention, subsequent use is facilitated and the potential technical fields of application are broadened.Advantageously, the PBO derivatives used are those conforming to formula 1, in which R and R' are identical and are in the para position relative to the peroxide group. In a more preferred embodiment, the derivatives conform to formulas 1b, 1c, and 1d. The compound of formula 1b has two fluorine atoms as substituents R and R', which exert an electron-withdrawing inductive effect on the aromatic ring to which they are bonded. The compound of formula 1c has two methoxy groups (-OCH3) as substituents R and R', which exert an electron-donating mesomeric effect on the aromatic ring to which they are bonded. The compound of formula 1d has acetoxy groups (-C(=O)OCH3) as substituents R and R', which exert an electron-withdrawing mesomeric effect on the aromatic ring to which they are bonded.

[0118] The process was carried out in air using unactivated truck tire waste granules. The effect of the different R and R' substituents is illustrated in Table 11. Each of the BPO derivatives (1b, 1c, and 1d) results in a marked improvement in TDV. Compounds 1b and 1d result in a twofold improvement in TDV. Compounds 1b and 1c also result in a notable increase in TDF, but this remains below 30%. Compound 1d, on the other hand, results in a decrease in TDF to 2%, thus making the process highly selective. Surprisingly, whether the aromatic ring has its electron density increased by the effect of electron-donating substituents or its electron density depleted by the effect of electron-withdrawing substituents, the TDV remains significantly increased with the substituted BPO derivatives containing electron-donating or electron-withdrawing substituents R and R'.

[0119] This therefore allows for the synthesis of a wide variety of functionalized oligomers. The results obtained when compound 1d is used in the process are particularly interesting in terms of selectivity and TDV. Table 11 Devulcanizing agent Volume of xylene (ml) Time (hours) Temperature (°C) V TDF 1a 25 4 80 31,5% 7% 1b 25 4 80 57,9% 27% 1c 25 4 80 50,2% 27% 1d 25 4 80 60,4% 2%

[0120] According to this embodiment, other benzoyl peroxide (BPO) derivatives have been used as ADs. These compounds are designated 1e, 1f, 1g, and 1h. Compound 1e contains two methyl groups (-CH3) as substituents R and R', which exert an electron-donating inductive effect on the aromatic ring to which they are bonded. Compound 1f contains two nitro groups (-NO2) as substituents R and R', which exert an electron-withdrawing mesomeric effect on the aromatic ring to which they are bonded. Compound 1g contains two chlorine atoms in the ortho position as substituents R and R', which exert an electron-withdrawing inductive effect on the aromatic ring to which they are bonded. Compound 1h contains two bromine atoms as substituents R and R', which exert an electron-withdrawing inductive effect on the aromatic ring to which they are bonded.

[0121] The process was carried out in air using unactivated truck tire waste granules. The effect of the different R and R' substituents is illustrated in Table 12. All the BPO derivatives presented resulted in a marked improvement in TDV. Compounds 1e, 1g, and 1h resulted in a TDV improvement greater than twofold. Compound 1f also resulted in a notable increase in TDF, but this remained below 30%. Compounds 1f and 1h also resulted in a decrease in TDF of 6% and 3%, respectively, thus making the process highly selective. Here again, whether the aromatic ring's electron density was increased by the effect of electron-donating substituents or depleted by electron-withdrawing substituents, the TDV remained significantly increased with the substituted BPO derivatives containing electron-donating or electron-withdrawing R and R' substituents.Regarding compound 1g, it should be noted that to obtain TDV levels equivalent to the other compounds presented (1b, 1c, 1d, 1e, 1f, and 1h), a reaction time of three hours was chosen. A reaction time of four hours resulted in a TDV equivalent to that obtained with compound 1a and a substantial increase in TDF.

[0122] These results confirm the possibility of synthesizing a wide variety of functionalized oligomers. The results obtained when compounds 1f and 1h are used in the process are particularly interesting in terms of selectivity and TDV. The results obtained when compounds 1e and 1h are used in the process are particularly interesting in terms of TDV. Compounds 1d and 1h appear especially promising due to their high TDV and low TDF (selective reaction, i.e., minimal depolymerization). Table 12 Devulcanizing agent Volume of xylene (ml) Time (hours) Temperature (°C) V TDF 1e 25 4 80 65,2% 12% 1f 25 4 80 52,1% 6% 1g 25 3 80 60,6% 14,8% 1h 25 4 80 62,2% 3%

[0123] According to a third embodiment, the solvent used in the process is trihexyltetradecylphosphonium chloride, an ionic liquid marketed under the name "Cyphos 101," the active pharmaceutical ingredient (API) used is benzoyl peroxide of formula 1a, and the process is carried out under air or an inert atmosphere. The use of an ionic liquid as the solvent automatically induces the swelling of the waste material, concurrently with devulcanization. This increases the waste volume (WV) as discussed previously. Furthermore, the use of an ionic liquid as the solvent leads to the precipitation of the synthesized functionalized oligomers. Consequently, the process can be carried out continuously and no longer requires a subsequent extraction step after devulcanization.

[0124] According to the third embodiment, additional experiments were conducted to illustrate the effect of the solvent. TDV and TDF were measured after the process was carried out in a eutectic solvent, choline chloride / urea (2a), and in ionic liquids, specifically Cyphos 101 (2b) and dioctylimidazolium bromide (DOIM / BR) (2c), respectively. The process was performed under air using unactivated truck tire waste granules. BPO was used as the active solvent. The results are reported in Table 13.

[0125] In the case of "Cyphos 101," the extraction of the devulcanization reaction products was insufficient to determine the TDF. Comparing these results with those obtained for compound 1a (BPO) in Table 11, it is observed that the TDV is considerably increased when ionic liquids or eutectic solvents are used. Conversely, a slight increase in TDF is also observed when a eutectic solvent is used, and a substantial increase when an ionic liquid is used. Table 13 Solvent Solvent volume (ml) Time (hours) Temperature (°C) V TDF 2a 25 4 80 54,2% 10% 2b 25 4 80 45,6% - 2c 25 4 80 53,7% 21%

[0126] The results presented above demonstrate that the polymer synthesis process by devulcanization according to the invention makes it possible, among other things, to obtain functionalized polymers that can contain a large number of different substituents, lower depolymerization rates than those obtained through the processes usually used and higher devulcanization rates than those obtained through the processes usually used.

Claims

1. Process for synthesizing polymers by devulcanization from elastomer-containing waste, said process comprising: - a) bringing said elastomer-containing waste into contact with a solvent in the presence of an agent for the devulcanization of crosslinking nodes that comprise a sulfur atom bonded to another sulfur atom or to a carbon atom, - b) heating the mixture obtained in step a), to a temperature of between 20°C and 250°C for a duration of between 15 minutes and 24 hours, said process being characterized in that: - the devulcanization agent is a compound according to formula (1) in which R and R' are identical or different and each represent, independently of one another, a substituent exerting a donating mesomeric effect or a withdrawing mesomeric effect or a donating inductive effect or a withdrawing inductive effect, R and R' are chosen independently of one another from the group comprising hydrogen (-H), halogen atoms chosen from iodine, bromine, fluorine and chlorine, the group of (C1-C18)alkyls, primary amines (-NH2), secondary amines (-NHRa1, Ra1 being chosen from (C1-C5) alkyl groups and aromatic rings) or tertiary amines (-NRa1Ra2, where Ra1 and Ra2, which may be identical or different, may each independently of one another be a (C1-C5) alkyl group or an aromatic ring), hydroxyl (-OH), alkoxides (or a salt) (Ra1-O-, Ra1 being chosen from (C1-C5) alkyl groups and aromatic rings), (C1-C5) alkoxy groups, a thiol (-SH), thioethers (-SRa1, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings), a thiolate (or a salt) (Ra1-S-, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings), an aromatic ring, a conjugate base of a carboxylic acid (-COO-), a carboxylic group (-COOH), esters (-CO2 Ra1, Ra1 being chosen from (C1-C5)alkyl groups and heterocycles), an aldehyde group (-CHO), a carbonyl (-COR), a nitro group (-NO2), a nitrile group (-CN), a sulfonyl group (-SO2-), a sulfonate group (salt or acid) (-SO3), a sulfone (-SO2R), a phosphate group (-O-PO(ORa1) (ORa2), where Ra1 and Ra2, which may be identical or different, may each independently of one another be a hydrogen or (C1-C5)alkyl group or an aromatic ring), a primary amide group (-CONH2), secondary amide group (-CONHRa1, Ra1 being chosen from (C1-C5) alkyl groups and aromatic rings) or tertiary amide group (-CONRa1Ra2, Ra1 and Ra2, which may be identical or different, may each independently of one another be a (C1-C5)alkyl group or an aromatic ring) and R, R' or both are different from a hydrogen atom.

2. Process according to Claim 1, in which the concentration of devulcanization agent is such that the ratio between said concentration of devulcanization agent, expressed as parts per hundred of elastomer (phr), and a volume of solvent, expressed in ml, is: - greater than 0.3 phr / ml of solvent or less than 0.2 phr / ml of solvent when the process is carried out under air, - greater than 0.06 phr / ml of solvent when the process is carried out under an inert atmosphere.

3. Process according to Claim 1 or 2, in which the solvent is an organic solvent or an ionic liquid or a deep eutectic solvent or the mixture thereof.

4. Process according to any one of Claims 1 to 3, characterized in that the duration of heating of the mixture is between 2 hours and 4 hours when the process is carried out under an inert atmosphere.

5. Process according to any one of Claims 1 to 3, in which the duration of heating of the mixture is between 3 hours and 5 hours when the process is carried out under air.

6. Process according to any one of Claims 1 to 5, characterized in that it comprises, prior to step a), a step of activating the elastomer-containing waste by lyophilization or by swelling.

7. Process according to Claim 6, in which the devulcanization reaction and the step of activating the elastomer-containing waste are performed continuously.

8. Process according to any one of Claims 1 to 7, characterized in that the synthesis of the polymers by devulcanization is carried out from highly vulcanized elastomer waste.

9. Functionalized elastomer according to formula 3 or 3', in which x is an integer between 0 and 6, n is an integer between 6 and 600, m is an integer between 6 and 600, Y is a hydrogen atom or a methyl group, and R and R', which may be identical or different for each unit, are chosen from the group comprising halogen atoms chosen from iodine, bromine, fluorine and chlorine, the group of (C1-C18)alkyls, primary amines (-NH2), secondary amines (-NHRa1, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings) or tertiary amines (-NRa1Ra2, where Ra1 and Ra2, which may be identical or different, may each independently of one another be a (C1-C5)alkyl group or an aromatic ring), hydroxyl (-OH), alkoxides (or a salt) (Ra1-O-, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings), (C1-C5)alkoxy groups, a thiol (-SH), thioethers (-SRa1, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings), a thiolate (or a salt) (Ra1-S-, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings), an aromatic ring, a conjugate base of a carboxylic acid (-COO-), a carboxylic group (-COOH), esters (-CO2 Ra1, Ra1 being chosen from (C1-C5)alkyl groups and heterocycles), an aldehyde group (-CHO), a carbonyl (-COR), a nitro group (-NO2), a nitrile group (-CN), a sulfonyl group (-SO2-), a sulfonate group (salt or acid) (-SO3), a sulfone (-SO2R), a phosphate group (-O-PO (ORa1) (ORa2), where Ra1 and Ra2, which may be identical or different, may each independently of one another be a hydrogen or (C1-C5)alkyl group or an aromatic ring), a primary amide group (-CONH2), secondary amide group (-CONHRa1, Ra1 being chosen from (C1-C5)alkyl groups and aromatic rings) or tertiary amide group (-CONRa1Ra2, Ra1 and Ra2, which may be identical or different, may each independently of one another be a (C1-C5)alkyl group or an aromatic ring).

10. Polymer composition obtained by the process according to any one of Claims 1 to 8.

11. Use of the compositions according to Claim 10 as an additive to fresh or new elastomer mixtures, as additives or reagents of surfactant, crosslinking agent or chain extender type.

12. Use of functionalized elastomers according to Claim 9 as materials, in particular as thermoplastic elastomers or elastomers for the biomedical field.