Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
  • C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
  • C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
  • C08J11/26—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds containing carboxylic acid groups, their anhydrides or esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
  • C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
  • C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L17/00—Compositions of reclaimed rubber
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L19/00—Compositions of rubbers not provided for in groups C08L7/00 - C08L17/00
  • C08L19/003—Precrosslinked rubber; Scrap rubber; Used vulcanised rubber
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2319/00—Characterised by the use of rubbers not provided for in groups C08J2307/00 - C08J2317/00
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2321/00—Characterised by the use of unspecified rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/02—Applications for biomedical use
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2207/00—Properties characterising the ingredient of the composition
  • C08L2207/04—Thermoplastic elastomer
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

• TITLE Synthesis of polymers functionalized by devulcanization from waste containing elastomers.
• the present invention relates to the field of the treatment of waste containing elastomers, of natural and / or synthetic origin.
• the invention targets, in particular, waste containing rubber, the major part of which is composed of waste tires.
• the present invention relates to the treatment of waste containing highly vulcanized elastomers, such as for example truck tire waste.
• Energy recovery from waste rubber is known in the state of the prior art. Energy recovery consists of incinerating rubber waste to produce energy. Energy recovery is extremely polluting.
• Chemical upgrading of rubber waste is also known in the state of the prior art. Chemical upgrading includes pyrolysis and devulcanization. Pyrolysis consists in breaking down rubber waste in the partial or complete presence of oxygen in order to obtain, among other things, a pyrolytic oil. Pyrolysis of waste rubber is a very expensive process.
• Devulcanization consists of breaking the crosslinking nodes by causing the breaking of carbon-sulfur bonds and / or disulfide bridges so as to partially or completely break the three-dimensional structure of the vulcanized rubber.
• Mechanical devulcanization, microwave devulcanization and chemical devulcanization are known in the state of the art. Mechanical devulcanization is carried out by extrusion and causes non-selective breaking of the disulphide bridges, the carbon-carbon bonds of the polymer chain also being broken.
• Microwave devulcanization aims to break carbon-sulfur bonds or disulfide bridges by emission of defined microwaves.
• this method causes a very significant rise in temperature of the waste in a few seconds. This sudden rise in temperature results in the breaking of the carbon-carbon bonds of the polymer chain.
• Metathesis has the major disadvantage of being a balanced reaction preventing the obtaining of a high degree of devulcanization.
• An object of the invention is to overcome these drawbacks and in particular to provide a process for the synthesis of polymers by devulcanization of waste containing elastomers.
• Another aim is to provide a process for the synthesis of polymers by devulcanization of waste containing elastomers making it possible to obtain high devulcanization rates from highly vulcanized rubber waste.
• Another aim is to provide a process for the synthesis of polymers by devulcanization of waste containing elastomers making it possible to synthesize functionalized polymers.
• a process for synthesizing polymers by devulcanization from waste containing elastomers comprises:
• step a 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.
• the devulcanization agent is a radical initiator.
• the devulcanizing agent is an agent for devulcanizing crosslinking nodes comprising a sulfur atom bonded to another sulfur or to a carbon atom.
• the radical initiator is capable of forming one or more radicals.
• the devulcanizing agent is capable of forming radicals by homolysis. More preferably, the devulcanizing agent is a peroxide.
• radical initiator is a compound of formula (1)
• R and R ' are the same or different and each represent, independently of one another, a substituent exerting a mesomeric effect donor or a mesomeric withdrawing effect or an inductive donor effect or an inductive withdrawing effect, either
• 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, ie:
• R and R 'exerting a mesomeric donor effect, a mesomeric withdrawing effect, an inductive donor effect or an inductive withdrawing effect are chosen independently of one another from the group comprising hydrogen (-H ), the halogen atoms chosen from iodine, bromine, fluorine and chlorine, the group of (Ci-i 8 ) alkyls, primary amines (-NH 2 ), secondary (-NHRai Rai being chosen from (Ci-C 5 ) alkyl groups and aromatic rings) or tertiary (-NRaiRa 2 , where Rai and Ra2, which are identical or different, can each be independently of one another a (Ci-C 5 ) alkyl group or a aromatic ring), hydroxyl (-OH), alcoholates (or a salt) (Rai-O, Rai being chosen from (Ci-C 5 ) alkyl groups and aromatic rings), (Ci-C 5 groups ) alkoxy, a thiol (
• (Ci-Ci 8 ) alkyl means any linear or branched carbon chain having from 1 to 18 carbon atoms and includes all the alkyl groups having 1 to 18 carbon atoms such as for example the methyl, ethyl, n-propyl groups, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl.
• the (Ci-Ci 8 ) alkyl group comprises chains of 1 to 8 carbon atoms or (Ci-C 8 ) alkyl groups, in particular the methyl, ethyl, n-propyl, isopropyl, n-butyl groups, isobutyl, tert-butyl, neopentyl, isopentyl, hexyl, heptyl, octyl, more preferably chains of 1 to 5 carbon atoms or (Ci-C 5 ) alkyl such as, for example, methyl, ethyl, n-propyl, isopropyl groups , n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl and more preferably chains of 1 to 3 carbon atoms or (C 1 -C 3 ) alkyl, in particular methyl, ethyl, n-propyl groups
• (Ci-C 5 ) alkyl means any linear or branched carbon chain having 1 to 5 carbon atoms and includes all the alkyl groups having 1, 2, 3, 4 or 5 carbon atoms, in particular methyl groups, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl and isopentyl.
• (Ci-C 5 ) alkoxy is a 0- (Ci-C 5 ) alkyl group where the (Ci-C 5 ) alkyl group is as defined above. Mention may be made, by way of example, of methoxy, ethoxy, butoxy and pentoxy groups.
• aromatic ring includes aryl groups, in particular phenyl, benzyl, naphthyl, biphenyl and tetrahydronaphthyl groups as well as heterocycles, that is to say rings which, in addition to carbon atoms, also include heteroatoms such as nitrogen, oxygen and sulfur.
• R and R ′ each represent, independently of one another, a hydrogen atom, a fluorine atom, a methoxy group or an acetoxy group.
• R and R ' are identical and each represent a fluorine atom, a methoxy group or an acetoxy group.
• the radical initiator is a compound of formula (1)
• the polymers obtained by carrying out the process are functionalized polymers.
• the radical initiator is a compound of formula (1)
• 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, ie:
• R, R 'or both are different from a hydrogen atom.
• the process according to the invention makes it possible to obtain polymers.
• the process according to the invention makes it possible to obtain polymers, in particular elastomers.
• the polymers obtained are functionalized polymers of formula 2 and / or 2 ' , formula 2 '
• R and R ' are identical or different and are as defined above, 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 units, each comprising a functional group, which have been introduced along the polymer chain during devulcanization.
• R and R ' are different from a hydrogen atom.
• the functional group (s) is (are) introduced at the end of the polymer chain. within the polymer chain.
• the process according to the invention makes it possible to introduce the functional group (s) within the polymer chain, and thus to obtain functionalized polymers of formula 2 and / or
• the process according to the invention is based on the synthesis of polymers by devulcanization of the crosslinking nodes present in the waste from which the process is implemented.
• 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.
• the term “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 able to be recovered.
• a 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 the synthesis of polymer by devulcanization according to the invention or made from said waste.
• the waste containing elastomers can comprise:
• N BR Nirile Butadiene Rubber
• - can be waste of natural rubber (Natural Rubber or NR), and / or butyl rubber.
• the waste containing elastomers may be truck tire waste, referred to as highly vulcanized elastomeric waste. It is understood by highly vulcanized elastomers having a crosslinking density greater than 10 4 mol / ml, preferably greater than 10 3 mol / ml.
• highly vulcanized elastomers having a crosslinking density greater than 10 4 mol / ml, preferably greater than 10 3 mol / ml.
• the waste is pneumatic waste, it contains, once the metal parts have been removed, essentially rubber, called gum, and carbon black, called filler.
• the tire waste used is cut tire, shredded material, crumb or granulate, preferably crumb or granulate.
• the concentration of devulcanizing agent is:
• the concentration of AD is:
• the concentration of AD is:
• 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.
• the concentration of AD is between 0.06phr / ml and 8phr / ml of solvent.
• the concentration of AD is between 0.06phr / ml and 0.6phr / ml of solvent.
• an inert atmosphere is understood to mean an atmosphere which does not react under the conditions of implementation of the process. Mention may be made, by way of nonlimiting example, of an atmosphere composed predominantly of nitrogen and / or noble gas such as, for example, argon. Preferably, the atmosphere is composed of nitrogen and / or noble gas.
• step b of the process is carried out at a temperature of the mixture of between 20 ° C and 150 ° C, more preferably between 40 ° C and 120 ° C, more preferably, between between 60 ° C and 100 ° C. Most preferably, the process is carried out at a temperature of 80 ° C.
• the heating time is between 1 h and 8 h, more preferably between 1 and 6 h.
• R and R ′ are chosen from the groups comprising one or more carbon and / or oxygen and / or nitrogen and / or phosphorus and / or sulfur and / or halogen atoms.
• the polymers synthesized by the process according to the invention can be composed of a mixture comprising polymers and oligomers.
• the polymers synthesized are oligomers.
• the oligomers are considered to be a chain of monomers having a molar mass of less than 2000 g / mol.
• the solvent can be an organic solvent or an ionic liquid or a deep eutectic solvent or a mixture thereof.
• the ionic liquid can be chosen from phosphoniums, imadazoliums or pyridiniums.
• the ionic liquids according to the invention consist of an anion and a cation and can be of the following general formula: , in which
• n is an anion selected from the group comprising PF6, N03, F, Cl, Br G
• R 9 being selected from the group consisting of 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 anion mentioned above and (1 / n) being equal to 1 if the anion has a 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 R 1 , R 2 , R 3 , R 4 is zero,
• R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are identical or different, each being chosen from a group comprising hydrogen, halogen, alkoxy, substituted or unsubstituted alkyl, substituted aryl or unsubstituted, and R 1 - R 2 , R 2 - R 3 , R 3 - R 4 , R 4 - R 5 , R 5 - R 6 , R 6 -R 7 , R 7 -R 8 or R 8 -R can represent a ring with 5, 6 or 7 carbon atoms,
• Z 1 , Z 2 , Z 3 are identical or different and are chosen from a group comprising a carbon atom and a nitrogen atom, on the condition that at least one of the atoms Z 1 , Z 2 and Z 3 represents a nitrogen atom and when one of the Z 1 , Z 2 and Z 3 atoms is a nitrogen atom, the corresponding R 1 , R 2 , R 3 group is zero.
• the deep eutectic solvents according to the invention can be chosen from:
• such a mixture can be a mixture of 1-ethyl-3-methylimidazolium and aluminum chloride (AICI),
• the hydrogen bond donor can be urea or a derivative of urea
• the hydrogen bond donor can be urea or a derivative of urea and by way of nonlimiting example such mixture can be a mixture of aluminum chloride (AICI 3 ) and urea.
• the deep eutectic solvent can be a mixture of choline chloride and urea.
• the deep eutectic solvent can be a mixture of 1 mol / l choline chloride and 2 mol / l urea.
• Deep eutectic solvents can comprise, in part or totally, natural products from a mixture of aconitic acid and choline chloride, a mixture of malic acid and glucose, a mixture of malic acid and fructose, a mixture 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.
• the solvent can be a mixture of solvents.
• the solvent may be a mixture of organic solvent and ionic liquid or a mixture of organic solvent and a deep eutectic.
• the organic solvent is chosen from nonpolar aromatic or aliphatic solvents.
• the organic solvent is xylene.
• the heating time of the mixture can be between 1 and 12 hours when the process is carried out under an inert atmosphere.
• the heating time of the mixture can be between 2 hours and 4 hours when the process is carried out under an inert atmosphere.
• the heating time of the mixture is 3 hours when the process is carried out under an inert atmosphere.
• the heating time of the mixture can be between 1 and 12 hours when the process is carried out in air.
• the heating time of the mixture can be between 3 hours and 5 hours when the process is carried out in air.
• the heating time of the mixture is 4 hours when the process is carried out in air.
• the concentration of AD is less than 0.2phr / ml of solvent.
• the method may comprise, prior to step a), a step of activating the waste containing elastomers, by lyophilization or by swelling or by treatment with supercritical CO 2 .
• the swelling can be carried out in an organic solvent, an ionic liquid or a deep eutectic solvent.
• Lyophilization can be carried out directly in water and then the water is removed by sublimation.
• the lyophilization can be carried out in a solvent other than water, in this case a step of exchanging the soil from the solvent, which is different from water, to water is carried out prior to the sublimation step. .
• the waste is swelled in fluid C0 2 and then the C0 2 is removed by evaporation.
• the swelling activation step can be carried out in a solvent identical to or different from that used during the implementation of the devulcanization.
• the step of activation by swelling can be carried out:
• the organic dipole moment solvent included between 0.5 and 2.5 Debye is an aprotic solvent.
• the organic solvent with a dipole moment of between 0.5 and 2.5 Debye is dichloromethane (DCM) or tetrahydrofuran (THF).
• the swelling step is carried out outside the mixture, prior to the vulcanization.
• the process can also comprise, subsequent to step b), a step of separating the polymers obtained. This step can be carried out by any technique known to those skilled in the art, for example by filtration, centrifugation, precipitation.
• the liquid phase is recovered, which contains the polymers.
• the solid phase which contains the carbon black, can be reused in a new formulation.
• the separation step can comprise a step:
• 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 dissolve oligomers so as to form oligomers soluble in said solvent.
• the devulcanization reaction and the step of activating the waste rubber can be carried out continuously.
• the devulcanization reaction and the step of activating the waste containing elastomers are carried out continuously, they are carried out concomitantly.
• the devulcanization reaction and the step of activating the waste containing elastomers are carried out continuously, they are carried out in the mixture.
• the solvent of the mixture is an ionic liquid or a deep eutectic.
• the devulcanization reaction and the step of activating the waste containing elastomers are carried out continuously in an ionic liquid or a deep eutectic, the polymers obtained precipitate directly in the mixture.
• the process according to the first aspect of the invention is a recycling process making it possible to recover waste comprising elastomers.
• x is an integer between 0 and 6, preferably equal to 0, 1, 2,
• n represents the number of units, each comprising a functional group which has been introduced along the polymer chain during devulcanization, and is an integer between 6 and 600
• m represents the number of monomers that the polymer comprises and is an integer between 6 and 600
• Y is a hydrogen atom or a methyl group
• R and R ' are chosen from the group comprising hydrogen (-H), the halogen atoms chosen from iodine, bromine, fluorine and chlorine, the group of ( Ci-i 8 ) alkyl, the primary amines (-NH 2 ), secondary (-NHRai Rai being chosen from the groups (Ci-C 5 ) alkyls and aromatic rings) or tertiary (-NRaiRa 2 , where Rai and Ra2 identical or different can each be independently of one another a (Ci-C 5 ) alkyl group or an aromatic ring), hydroxyl (-OH), alcoholates (or a salt) (Rai-O-, Rai being chosen from (Ci-C 5 ) alkyl groups and aromatic rings), (Ci-C 5 ) alkoxy groups, a thiol (-SH), thioether (-SRai, Rai being chosen from (Ci- C 5 ) alkyls and aromatic rings), a thio
• (Ci-Ci 8 ) alkyl means any linear or branched carbon chain having from 1 to 18 carbon atoms and includes all the alkyl groups having 1 to 18 carbon atoms such as for example the methyl, ethyl, n-propyl groups, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl.
• the group of (Ci-Ci 8 ) alkyl comprises chains of 1 to 8 carbon atoms or (Ci-C 8 ) alkyl groups, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl, hexyl, heptyl, octyl groups, more preferably chains of 1 to 5 carbon atoms or (Ci-C 5 ) alkyl such as for example the groups methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, isopentyl and more preferably preferred are chains of 1 to 3 carbon atoms or (C1-C) alkyl, in particular methyl, ethyl, n-propyl and isoprop
• (Ci-C 5 ) alkyl means any linear or branched carbon chain having 1 to 5 carbon atoms and includes all alkyl groups having 1, 2, 3, 4 or 5 carbon atoms, in particular groups methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl and isopentyl.
• (Ci-C 5 ) alkoxy is a 0- (Ci-C 5 ) alkyl group where the (Ci-C 5 ) alkyl group is as defined above. Mention may be made, by way of example, of methoxy, ethoxy, butoxy and pentoxy groups.
• R or R 'each represents, independently of one another, a hydrogen atom, a fluorine atom, a methoxy group or an acetoxy group.
• R and R ′ may be different from a hydrogen atom.
• R and R ′ represent a fluorine atom, a methoxy group or an acetoxy group.
• the functional group (s) is (are) introduced into the polymer chain.
• the process according to the invention makes it possible to introduce the functional group (s) into the polymer chain, and thus to obtain functionalized polymers of formula 3 and / or 3 '.
• Formula 4 illustrates the general chemical structure of an elastomer. , formula 4.
• the use of functionalized elastomers according to the second aspect of the invention is proposed as elastomeric materials, thermoplastic elastomers or elastomers for the biomedical sector.
• compositions of polymers capable of being obtained by the process according to the first or the second aspect of the invention.
• the process according to the invention makes it possible to obtain polymer compositions.
• Said polymer compositions may consist of oligomers or of 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 includes elastomers.
• a use of the polymer compositions obtained according to the fourth aspect of the invention as an additive to mixtures of fresh or new elastomers, as additives or reagents such as surfactants, agents. crosslinkers or chain extenders.
• the devulcanization process is implemented from aggregates or powder of truck tire waste.
• the overall reaction of the chemical devulcanization process by breaking the disulfide bridges by means of a devulcanizing agent is presented in reaction schemes 1 and 1 'below.
• This devulcanization process therefore constitutes a route for synthesizing polymers from pneumatic waste.
• the type of polymer synthesized in terms of chain length, is mainly governed by the degree of polymerization of the elastomers contained in the waste from which the process is carried out.
• the waste containing elastomers from which the method is implemented comes from truck tire waste.
• the synthesis generates the production of oligomers or of a mixture comprising polymers and oligomers.
• the polymers obtained according to reaction scheme 1 comprise a number, denoted n, of units, each comprising a functional group that has been introduced along the polymer chain during devulcanization, which is between 6 and 600, a number of atoms of sulfur, denoted x, connecting the functional group to the polymer chain which is between 0 and 6, and a number, denoted m, of monomers which the polymer comprises which is between 6 and 600.
• Truck tire waste is known to be highly vulcanized.
• the devulcanizing agent is introduced in an amount of 6% by mass relative to the rubber waste.
• Those skilled in the art designate this ratio by "phr” as being 6 parts of AD per 100 parts of rubber waste by mass, “phr” for "per hundred rubber”.
• the mass of initial waste, during the implementation of each of the embodiments presented, is 300 mg.
• an additional step aimed at recovering the synthesized polymers is implemented: it consists in treating the devulcanized waste with acetone for 24 hours to recover the polymers. functionalized.
• the polymers synthesized are in suspension and / or solvated, those skilled in the art will be able to choose the most suitable chemical separation or extraction process for recovering them.
• the degree of devulcanization is determined by the Flory principle through the variation of the crosslinking density according to the process described by Paul J. Flory and John Rehner, The Journal of Chemical Physics, 1943, vol.11, pp. 521. It therefore allows specific measurement of disulfide bridges and carbon-sulfur bond breaks. The value of the TDV will therefore make it possible to specifically assess the efficiency of the devulcanization reaction.
• the TDV is generally determined from sol-gel measurements, in general by means of a Soxhlet extraction process, and in particular from the soluble fraction of the polymer. devulcanized.
• the determined soluble fraction includes breaks in disulfide bridges and carbon-sulfur bonds, but also breaks in carbon-carbon bonds in the polymer chain.
• the inventors have deduced that the main source of depolymerization is that which is generated by the reaction of AD on polyisoprene carbon-carbon double bonds.
• the degree of functionalization, denoted TDF in the remainder of the description, of the polyisoprene contained in the pneumatic waste was studied in parallel under conditions identical to those used during of the implementation of the process.
• the polyisoprene chosen to determine the TDF exhibits a degree of polymerization equivalent to that of the waste truck tires used.
• TDF The value of the TDF will therefore make it possible to accurately assess the specificity of the devulcanization reaction with respect to disulfide bridges and carbon-sulfur bonds.
• a process which makes it possible to obtain a TDF of less than 30% will be considered to have an acceptable selectivity.
• the balance reaction of depolymerization of polyisoprene by reaction of the devulcanizing agent on the carbon-carbon double bonds of the polyisoprene or polybutadiene is presented by reaction scheme 2 below.
• reaction scheme 3 The balance reaction of depolymerization of polyisoprene by reaction of the devulcanizing agent on the carbon-carbon double bonds of the polyisoprene or polybutadiene can be completed by reaction scheme 3 below. Reaction scheme 3
• the method for synthesizing oligomers by devulcanization is carried out in air and the AD is benzoyl peroxide of formula la, which corresponds to the compound of formula 1 in which R and R 'are hydrogen atoms,
• the solvent used is xylene.
• Table 1 illustrates the effect of temperature on the process according to the first embodiment. It is noted that a change from a temperature of 80 ° C to a temperature of 100 ° C generates a multiplication by a factor of two of the TDV but a multiplication by a factor of twelve of the TDF. This demonstrates that the depolymerization reaction is important above 80 ° C.
• Table 2 illustrates the effect of time on the method according to the first embodiment.
• Table 2 shows that the TDV increases to reach a maximum at a reaction time of 4 hours and then slowly decreases.
• the TDF is relatively stable and weak. It goes from 5% for reaction times of two and three hours to 7% for reaction times of four and five hours.
• Table 3 illustrates the effect of the AD concentration on the process according to the first embodiment.
• the TDV is relatively low and the TDF is 5 %.
• the TDV is 61, 3% and the TDF of 82%.
• the TDV is 61.2% and the TDF of 18%.
• the TDV obtained for a high concentration of AD is similar to that obtained for a low concentration of AD.
• the high value of TDF observed during the implementation of the process with a high concentration of AD confirms the presence of a side reaction of depolymerization.
• the TDV obtained for highly vulcanized waste such as truck tire waste exhibiting a crosslinking density of 13.5.10 4 mol / ml is at least equal to, or even greater than, that obtained for rubber having crosslinking densities, typically 2.6.10 4 mol / ml, which are markedly lower. It is observed that for low concentrations of AD, the process makes it possible to obtain good values of TDV and has very good selectivity, 18% of TDF.
• the process is carried out under an inert atmosphere, under argon, the AD is benzoyl peroxide of formula la and the solvent used is xylene.
• Table 4 illustrates the effect of the inert atmosphere on the TDV according to the second embodiment.
• the TDV is multiplied by a factor of two compared to the process carried out under the same conditions in air.
• the TDF is also multiplied by a factor of two but keeps a low value.
• Table 5 illustrates the effect of time on the method according to the second embodiment.
• Table 5 shows that TDV increases to a maximum at a reaction time of 3 hours and then decreases rapidly. For its part, the TDF grows over time. It goes from 10% for reaction times of two and three hours to 14% and then 16% for reaction times of four and five hours.
• Table 6 illustrates the effect of the AD concentration on the process according to the second embodiment. It is observed that a decrease in the concentration of AD leads to a decrease in TDV and an increase in TDF. Also, unlike the implementation of the process in air, the AD concentration values greater than 0.06phr / ml of solvent are to be preferred when the process is carried out under argon. This indicates that when the process is carried out under argon, in addition to the reactions of devulcanization and radical depolymerization, an additional reaction appears. It may for example be a crosslinking of sulfur radicals on disulfide bridges and / or double bonds of the polymer chain.
• a step for activating the pneumatic waste aggregates is carried out prior to the devulcanization reaction.
• the activation comprises a step of swelling the aggregates.
• Table 7 illustrates the influence of the type of solvent on the rate of swelling of the aggregates and on the part of the aggregates which have been solubilized by the solvent.
• This swelling step consists in introducing a given quantity of pneumatic waste granulates in a solvent for a given time and in recovering the part of the pneumatic waste which has been solubilized by the solvent. The experiments were each carried out three times and the calculated mean was reported in Table 7.
• the non-polar solvents, pentane (dipole moment p 0.2D), are not very effective.
• an apolar solvent has a polar moment of less than 0.5D and that a polar solvent has a dipole moment greater than 2D or even 2.5D.
• the activation comprises a step of lyophilization of the aggregates.
• the aggregates are swollen in DCM for 24 hours according to the process described in the first variant. Then, an exchange of DCM-ethanol and then ethanol-water solvent is carried out. The aggregates swollen with water are then frozen and lyophilized for 48 hours.
• Table 8 illustrates the effect of activation by lyophilization on the devulcanization of the pneumatic waste aggregates.
• the TDV When the process is carried out in air from lyophilized aggregates, the TDV is markedly higher than that obtained with aggregates which have not undergone activation. The TDF remains unchanged and low.
• the TDV decreases significantly while the TDF remains constant. This indicates that the radical crosslinking which appears during the implementation of the process under argon is exacerbated when the pneumatic waste is lyophilized.
• the concentration of AD decreases, from 0.24phr / ml of solvent to 0.06phr / ml of solvent, TDV decreases and TDF increases. This further confirms the results above and those presented in Table 6 according to which the radical crosslinking is amplified when the concentration of AD decreases.
• the activation comprises a step of swelling the aggregates in an ionic liquid, trihexylte-tradecylphosphonium chloride, known under the trade name “Cyphos 101” for 12 hours.
• Table 9 illustrates the effect of implementing the process in air from the aggregates which have undergone a swelling step in the ionic liquid. Compared to TDV and TDF obtained in the absence of activation, there is a two-fold increase in TDV and a marked increase in TDF. Compared to the TDV and TDF obtained during activation by lyophilization, there is a noticeable increase in TDV and a marked increase in TDF.
• the activation comprises a step of swelling the aggregates by treatment with supercritical C0 2 (ScC0 2 ).
• the activation step consists in treating the aggregates by swelling in ethanol or acetone, then in carrying out a solvent exchange between the ethanol, or the acetone, and the scC0 2 in a dehydrator.
• Table 10 The results of the synthesis of polymers by devulcanization implemented from aggregates swollen by treatment with ScCO 2 are presented in Table 10.
• the devulcanization agent used corresponds to formula 1 in which R and R ′ are different from a hydrogen atom.
• These ADs are therefore derivatives of benzoyl peroxide (BPO).
• BPO benzoyl peroxide
• the use of such derivatives makes it possible to synthesize, by devulcanization of rubber waste, oligomers functionalized according to formula 3 and / or 3 ′.
• the synthesized oligomers originate from rubber waste, the fact that they are functionalized constitutes an additional advantage for their subsequent use.
• the functional group can comprise a wide choice of substituents R, R 'as proposed according to the invention, the subsequent use is facilitated and the technical fields of potential applications are widened.
• the PBO derivatives used are those corresponding to formula 1 in which R and R ′ are identical and are in the para position relative to the peroxide group.
• the derivatives correspond to formulas Ib, Ic and Id.
• the compound of formula lb has two fluorine atoms as substituents R and R 'which exert an effect of inductive attractor type on the aromatic ring to which they are linked.
• the compound of formula Ie has two methoxy groups (-OCH) as substituent R and R 'which exert an effect of the donor mesomer type on the aromatic ring to which they are linked.
• the aromatic ring sees its electron density increased by the effect of the substituents exerting a donor effect or if it sees its electron density depleted by the effect of the substituents exerting an attracting effect, the TDV remains markedly increased with substituted derivatives of BPO comprising substituents R and R 'donors or attractors.
• ADs other derivatives of benzoyl peroxide (BPO) were used as ADs.
• These compounds are denoted le, lf, lg and lh.
• the compound it contains two methyl groups (-CH 3 ) as substituents R and R 'which exert an inductive donor type effect on the aromatic ring to which they are linked.
• the compound 1f comprises two nitro groups (-N0 2 ) as substituent R and R 'which exert an effect of the withdrawing mesomer type on the aromatic ring to which they are linked.
• Compound Ig comprises two chlorine atoms in the ortho position as substituents R and R 'which exert an effect of inductive attractor type on the aromatic ring to which they are linked.
• Compound lh comprises two Bromine atoms as substituents R and R 'which exert an effect of inductive attractor type on the aromatic ring to which they are linked.
• substituted BPO comprising R and R 'substituents donors or attractors.
• reaction time of three hours was chosen.
• a reaction time of 4 h results in a TDV equivalent to that obtained with compound la and in a substantial increase in TDF.
• results obtained when the compounds 1f and 1h are used during the implementation of the process are particularly advantageous in terms of selectivity and TDV.
• results obtained when the compounds Ia and Ih are used during the implementation of the process are particularly interesting in terms of TDV.
• Compounds 1d and 1h appear to be particularly advantageous as the TDV which they allow to obtain is high and the TDF is low (selective reaction, that is to say little depolymerization).
• the solvent used during the implementation of the process is trihexyltetradecylphosphonium chloride, an ionic liquid marketed under the name “Cyphos 101”, the AD used is benzoyl peroxide of formula la. and the process is carried out in air or in an inert atmosphere.
• the use of an ionic liquid as solvent automatically generates the implementation of the swelling of the waste, concomitantly with the devulcanization. This allows the TDV to be increased as discussed previously.
• the use of an ionic liquid as a solvent in fact causes the precipitation of the synthesized functionalized oligomers. Therefore the process can be implemented continuously and no longer requires an extraction step subsequent to the implementation of the devulcanization.
• TDV and TDF were measured after the implementation of the method in a eutectic solvent, choline chloride / urea, denoted 2a, and in ionic liquids, respectively in “Cyphos 101”, denoted 2b, and in du.
• Dioctylimidazolium bromide ([DOIM] [BR]) noted 2c.
• the process was carried out in air using aggregates of truck tire waste which had not undergone prior activation.
• the BPO was used as AD. The results are reported in Table 13.

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