Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F293/00—Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F36/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
  • C08F36/02—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
  • C08F36/04—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F36/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
  • C08F36/02—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
  • C08F36/04—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
  • C08F36/14—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated containing elements other than carbon and hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
  • C08G63/08—Lactones or lactides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/50—Phosphorus bound to carbon only
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/52—Phosphorus bound to oxygen only
  • C08K5/527—Cyclic esters

Definitions

• the present invention relates to a process for preparing polydiene / polylactide copolymers by reactive extrusion.
• the inventors are more particularly concerned, within the scope of the invention, with the preparation of block-comb or triblock copolymers associating an elastomeric skeleton and rigid pendent or end blocks. These copolymers thus have thermoplastic elastomer properties.
• the invention is particularly directed to comb or triblock block copolymers which can be used as the material as such.
• thermoplastic elastomer properties combine the elastic properties of elastomers and the thermoplastic character, namely the ability to melt and reversibly heat-cure pendent or end blocks.
• thermoplastic polymers having a melting point greater than or equal to 100 ° C., advantageously ranging from 100 ° C. to 230 ° C., are required.
• Polylactic acid, PLA has a melting temperature within this range.
• the application JP 2012 158 738 describes tire compositions comprising a diene elastomer grafted with polylactic acid, PLA.
• the copolymer is obtained by reaction of the diene elastomeric polymer and the PLA polymer.
• the PLA content in the copolymer can be only low: at most 10 parts by weight per 100 parts of the diene elastomer.
• JP 5152804 describes the radical grafting of a PLA polymer on a diene elastomer in a biaxial extruder.
• a radical grafting is poorly controlled and also leads to the creation of bonds between the diene elastomer chains.
• PLA chains which have not reacted with the diene elastomer may remain.
• Reactive extrusion is a process mostly used for thermoplastics, so polymers with high glass transition or melting temperatures, if any. Reactive extrusion allows to work without solvent.
• the reactive extrusion makes it possible to perform all the steps (mixing, polymerization and purification / devolatilization) in the same reactor, the extruder.
• compositions comprising polylactic acid copolymers which may comprise up to 52% by weight of polybutadiene. These copolymers are not elastomers. In particular, in these copolymers the butadiene block has a number average molecular weight of less than 40,000 g / mol.
• lactide means the cyclic diester of lactic acid, that is to say 2-hydroxypropionic acid. Lactide has the following formula:
• lactide covers all possible stereoisomeric configurations of lactide: (R, R) -lactide, (S, S) -lactide and meso-lactide.
• polylactic acid or "PLA” or “polylactide” in the context of the invention means the polymer obtained by ring-opening polymerization of lactide.
• the repetitive unit of PLA can be represented by the formula - [CH (CH 3 ) -C (O) -O] n -, the asymmetric carbon being able to be of R or S configuration.
• the copolymer comprises pendant groups of this type at several points in the constitutive elastomer chain of the trunk. This includes the end or ends of the chain but is not limited to these locations.
• the copolymer also comprises at least one other pendant block of this type at another position in the chain.
• any range of values designated by the expression "between a and b" represents the range of values from more than a to less than b (i.e., terminals a and b excluded) while any range of values designated by the term “from a to b” means the range from a to b (i.e., including the strict limits a and b).
• the compounds mentioned in the description and used in the preparation of polymers or rubber compositions may be of fossil origin or biobased. In the latter case, they can be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. This includes polymers, plasticizers, fillers, etc.
• the subject of the present invention is a process for preparing a diene elastomer / polylactide copolymer, the mass percentage of polylactide being between 10% and 45% by weight, relative to the weight of the copolymer, characterized in that it is introduced into an extruder:
• an elastomer functionalized with at least one group bearing at least one function capable of initiating a ring-opening polymerization of lactide said functionalized elastomer has a number-average molar mass, Mn, of greater than 40,000 g / mol;
• the process according to the invention makes it possible to prepare a diene elastomer / polylactide copolymer which retains its elastomeric properties.
• the process according to the invention makes it possible, in particular, to prepare a diene / polylactide copolymer, in particular triblock or comb copolymer, having an elongation at break of at least 150%, as measured by the method described before the examples, paragraph "mechanical tests”.
• lactide reacts with the reactive function (s) carried by the functionalized elastomer group and then the lactide polymerizes, by ring opening, to form one or more several polylactide (PLA) block (s).
• the diene elastomer is functionalized by two terminal groups, each group bearing at least one function capable of initiating a ring-opening polymerization of lactide.
• the diene elastomer / polylactide copolymer which will thus be obtained in the case of two terminal groups bearing a single function will be a PLA-PLA-diene elastomer-PLA triblock.
• the diene elastomer is functionalized by several pendant groups, each group bearing at least one function capable of initiating a ring-opening polymerization of lactide. These groups are pendent along the trunk and thus at least one of these pendant groups is not terminal.
• the diene elastomer / polylactide copolymer which will thus be obtained will be a comb copolymer having a diene elastomer trunk and pendant PLA blocks along the trunk.
• the diene elastomer is functionalized by a terminal group carrying at least one function capable of initiating a ring-opening polymerization of lactide.
• the diene elastomer / polylactide copolymer which will thus be obtained in the case of the terminal group carrying a single function will be a diene PLA-diene elastomer block.
• This method thus allows controlled polymerization, by growth of a PLA chain from each initiator function carried by each group, during or at the end of the diene elastomer.
• the function able to initiate a ring-opening polymerization of lactide, also called initiator function is advantageously terminal.
• the elastomer is functionalized with at least two identical or different groups, each bearing at least one function capable of initiating a ring-opening polymerization of lactide, thus leading to diene elastomer / polylactide tri-block or comb copolymers.
• the diene elastomer functionalized with at least two groups may in particular be represented by the following formulas:
• the group A is a group carrying at least one function capable of initiating a ring-opening polymerization of lactide.
• the group A may be different within the same formula and from a formula (I) to a formula (II).
• the method comprises the following successive steps:
• step b Mixing of the components introduced in step a); then
• step b Introduction of the catalytic system to the mixture obtained following step b), the introduction of the catalytic system initiating the polymerization; then d. Introduction of a catalyst inhibitor to stop the polymerization; e. Recovery of the elastomeric diene / polylactide copolymer at the outlet of the extruder.
• Steps a) and b) make it possible to homogenize the mixture and to ensure that the subsequent polymerization proceeds optimally.
• the entire functionalized elastomer is introduced.
• the functionalized elastomer is advantageously dried beforehand.
• the residual water content in the diene elastomer is less than 2000 ppm, more preferably less than 1000 ppm.
• the residual water content in the lactide is less than 500 ppm, more preferably less than 300 ppm.
• steps a) and b) are advantageously carried out under anhydrous conditions, for example by scanning an inert gas such as nitrogen, in order to avoid any homopolymerization of the lactide.
• step a) all of the lactide or a portion of lactide can be introduced.
• step a all the lactide is introduced.
• a portion of the lactide is added, advantageously at least 50% by weight, relative to the total amount of lactide, more preferably at least 70% by weight.
• step c The remaining part of the lactide will be added during step c), before or simultaneously with the introduction of the catalytic system.
• the method comprises the following successive steps: at. Introduction into an extruder of a portion of lactide and said functionalized elastomer;
• step b Mixing of the components introduced in step a); then
• the polymerization of lactide begins with the addition of the catalyst system.
• the catalytic system comprises a catalyst allowing the ring-opening polymerization of lactide, which catalyst will be described later.
• the polymerization is conveniently conducted at a temperature of from 80 ° C to 200 ° C, more preferably from 100 ° C to 200 ° C, even more preferably from 150 ° C to 200 ° C.
• the process is characterized in that the polymerization is conducted in an extruder.
• Any type of extruder allowing the mixing of components can be used: single-screw extruder, two-stage extruder or co-kneader, twin screw, planetary gear, rings. Twin-screw extruders are particularly suitable.
• the extruder may allow a continuous or batch process.
• the L / D ratio (length / diameter) of the extruder is adapted as a function of the polymerization time, depending on the flow rate and the residence time.
• the L / D ratio may, for example, be greater than 20, more preferably greater than 40. It may for example be 56 for a continuous twin-screw extruder and a polymerization time of less than 30 minutes. In a batch process, it may for example be 5 or 6 for a micro-extruder and a polymerization time of less than 30 minutes.
• steps a) to e) are advantageously conducted in a single extruder, mainly for practical reasons. However, one could consider using an extruder for steps a) and b) and another extruder for steps c) to e).
• the mixture of steps a) and b) is advantageously carried out under a lower mixing than the mixture of the polymerization step c), in particular so as not to degrade the functionalized diene elastomer during steps a) and b).
• the skilled person It is possible to adapt the rotational speed of the screws of the extruder, its design in the mixing zones according to the mixing that it wishes to obtain.
• An inhibitor of the catalytic system is introduced during step d), of course after mixing in the preceding step for a time sufficient to reach the desired degree of polymerization.
• the process according to the invention may comprise a step of evaporation of unreacted volatile components, in particular unreacted lactide.
• the method according to the invention makes it possible to obtain satisfactory conversions in durations compatible with an industrial use.
• the polymerization time is advantageously less than 30 minutes, more advantageously it varies from 5 minutes to less than 30 minutes.
• step a an antioxidant agent which makes it possible to avoid degradation of the diene elastomer.
• This antioxidant agent may also make it possible to avoid depolymerization of the PLA blocks or couplings between the diene elastomer / polylactide copolymer chains formed.
• the antioxidant agent is described later.
• the polymerization is advantageously carried out in bulk, that is to say without adding additional solvent.
• the process may be continuous or discontinuous.
• the method is continuous. Steps a) to e) will therefore be simultaneous and will take place in different areas of the extruder.
• step a) will be conducted in a feed zone (located upstream in the extruder), and then step b) in a mixing zone.
• the extruder will include an introduction zone of the catalytic system and then a mixing zone.
• the extruder will include a catalyst system inhibitor introduction zone, mixing, and then evaporating the unreacted volatiles with exit and recovery of the copolymer.
• a downstream zone is an area closer to the exit of the extruder.
• FIG. 1 An exemplary embodiment of a continuous synthesis process of a copolymer according to the invention, for example a styrene-butadiene copolymer (SBR) / PLA, is shown in FIG. 1.
• a twin-screw extruder A comprising 15 mixing zones (Z1 to Z15, having the indicated temperature indicated), having a L / D ratio of 56, lactide 1 (40% by weight relative to the total weight of di-functionalized lactide + SBR) is introduced under a nitrogen atmosphere at a suitable flow rate, for example 400 g / h, in zone Z1, then, in zone Z2, a di-functionalized elastomer, for example an aromatic primary amine difunctionalized SBR, having a number-average molecular weight of 87300 g / mol, under a nitrogen atmosphere at a suitable flow rate, for example 600 g / h .
• a suitable flow rate for example 400 g / h
• the lactide and the functionalized elastomer are mixed for a sufficient time, for example 2.1 minutes.
• the catalytic system 3 is added in the form of a solution at a suitable flow rate, for example 0.136 ml / min.
• the catalyst system may for example be a 1/1 mol / mol mixture of Sn (oct) 2 and P (Ph 3 ) and the lactide / Sn (oct) 2 molar ratio is for example 700.
• the polymerization begins at this point. moment.
• an inhibitor of catalyst 4 is introduced to stop the polymerization.
• Zones Z10 to Z12 the unreacted lactide is evaporated under vacuum.
• the speed of rotation of the screws is for example 70 revolutions / min.
• the total flow rate is 1000 g / h.
• the extrudate is sent to a cooling bench B and then to a granulator C.
• the copolymer obtained has a linear triblock structure with a central elastomer block of 87300 g / mol bonded to two side blocks of PLA with a molar mass of about 10 000 g / mol, ie a molar mass of the triblock of about 10 10 000 g / mol.
• the conversion of lactide to PLA is greater than 90% and the majority of the residual lactide is removed in step e).
• Steps a) to e) will therefore be spread out over time and may take place in the same zone of the extruder.
• Steps a) to e) can thus be conducted in cycles, the product leaving the extrusion zone being fed back to the extruder.
• Step a) corresponds to the beginning of the first cycle.
• step b) is conducted for a predetermined number of cycles.
• step c) the catalytic system is introduced and then the predetermined number of cycles is carried out.
• step d) the inhibitor of the catalytic system is introduced and then the number of pre-determined cycles is carried out to evaporate the unreacted products before leaving and recovering the copolymer.
• the weight percentage of polylactide is between 10% and 45% by weight, advantageously up to 40% by weight, more preferably from 15% to 40% by weight.
• the mass percentage of lactide introduced advantageously varies from 12% to 47% by weight, relative to the total weight of functionalized diene elastomer introduced and lactide introduced.
• the ring opening polymerization reaction of lactide is conducted in the presence of a catalyst system, as known to those skilled in the art.
• a first example of a suitable catalytic system is that described in the patent application WO98 / 02480.
• This catalytic system comprises at least one catalyst and optionally at least one cocatalyst.
• the catalyst is of formula (M) (X 1 , X 2 .... X m ) n in which
• M is a metal selected from Group 2, 4, 8, 9, 10, 12, 13, 14 and 15 of the Periodic Table of Elements;
• X 1 , X 2 .... X m is a substituent selected from alkyl, aryl, oxide, carboxylate, halide, alkoxy, alkyl ester;
• n is an integer from 1 to 6
• n is an integer from 1 to 6, the values of m and n depend on the degree of oxidation of the metal ion.
• Alkyl denotes a linear or branched, saturated hydrocarbon group of 1 to 20 carbon atoms, in particular of 1 to 16 carbon atoms, in particular of 1 to 12 carbon atoms, in particular of 1 to 10 atoms, and more particularly from 1 to 6 carbon atoms.
• radicals such as methyl, ethyl, isopropyl, n-butyl, t-butyl, t-butylmethyl, n-propyl, pentyl, n-hexyl, 2-ethylbutyl, heptyl, octyl , nonyl, or decyl.
• Aryl refers to an aromatic ring comprising from 1 to 3 aromatic rings, optionally fused, from 6 to 20 carbon atoms, especially from 6 to 10 carbon atoms.
• aryl groups it is possible to mention phenyl, phenethyl, naphthyl or anthryl.
• Alkoxy refers to a group of the general formula R-O- where R is an alkyl group as defined above.
• R is an alkyl group as defined above.
• Halide means chloride, fluoride, iodide or bromide.
• Mg and Ca are preferred.
• group 4 the use of Ti, Zr and Hf may be mentioned.
• group 8 the use of Fe is preferred.
• group 12 the use of Zn is preferred.
• group 13 the use of Al, Ga, In and TI can be mentioned.
• group 14 the use of Sn is preferred.
• group 15 the use of Sb and Bi is preferred.
• M is selected from Sn, Zr, Hf, Zn, Bi and Ti.
• the use of an Sn catalyst may be particularly preferred.
• tin halides such as SnCl 2 , SnBr 2 , SnCl and SnBr 4 may be mentioned.
• oxides SnO and PbO can be mentioned.
• octoates for example, 2-ethyl hexanoate
• stearates acetates may be mentioned.
• Sn-octanoate (also known as Sn (II) bis 2-ethylhexanoate or simply as tin octoate), tin stearate, dibutyltin diacetate, butyltin tris (2- ethylhexanoate), tin (2-ethylhexanoate), bismuth (2-ethylhexanoate), tri-acetate tin, sodium (2-ethyl hexanoate), calcium stearate, magnesium stearate and zinc stearate can be mentioned.
• Ti (OiPr) 4 Ti (2-ethylhexanoate) 4 , Ti (2-ethylhexylate) 4 , Zr (OiPr) 4 , Bi (neodecanoate) 3 or Zn (lactate) 2 .
• Other suitable compounds include tetraphenyltin, Sb tris (ethylene glycolate), aluminum alkoxy and zinc aikoxy.
• the catalytic system may also comprise a cocatalyst, advantageously of formula
• Y is an element selected from the elements of group 15 and / or 16 of the periodic table
• aryls oxides, halides, alkoxy, aminoalkyls, thioalkyls, phenyloxy, aminoaryls, thioaryls, and compounds containing the elements of group 15 and / or 16 of the periodic table
• q is an integer from 1 to 6, and
• p is an integer from 1 to 6.
• the catalytic system comprises tin bis (2-ethylhexanoate) as catalyst and triphenylphosphine PPh 3 as co-catalyst.
• the molar ratio between the cocatalyst and the catalyst may be between 1/10 and 10/1, preferably between 1/3 and 3/1. More preferably, the molar ratio between the cocatalyst and the catalyst may be 1/1.
• the molar ratio between lactide and the catalyst may be less than 1000/1, in particular less than 900/1.
• the molar ratio between lactide and tin bis (2-ethylhexanoate) catalyst may range from 50/1 to 1000/1, preferably from 100/1 to 900/1, more preferably from 200/1 to 800/1.
• organic catalysts of the family of guanidines more particularly of TBD: 1,5,7-triazabicyclo [4.4.0] dec-5-ene) (cyclic guanidine organic catalysts, what is magic about triazabicyclodecene? Matthew K. Kiesewetter et al., J. Org Chem., 2009, 74, 6490-9496) or N-heterocyclic olefins (Highly polarized alkenes as organocatalysts for the polymerization of lactones and trimethylene carbonate, stefen naumann et al. ACS Macro Lett., 2016, 5, 134-138).
• step a it is possible to add, as of step a), an antioxidant agent.
• This antioxidant is preferably not very nucleophilic so as not to initiate the ring-opening polymerization of lactide.
• Antioxidants of PLA are described in US Pat. Nos. 6,143,863 or EP 912,624.
• Organophosphites such as bis (2,4-di-t-butylphenyl) pentraerythritol diphosphite (trade name: Ultranox® 626) are particularly effective.
• Hindered phenolic antioxidants such as Nrganox® 1070 are also particularly effective.
• the polymerization inhibitor (cata-killer) added during step d) of the process may also have an antioxidant effect.
• Inhibitors of the catalytic system used in the process of the invention are known to those skilled in the art.
• These include the following commercial products: Nrganox® 1425 or Nrganox® 195, which are both phosphonates, doverphos® S680 or doverphos® LP09, which are both phosphites, polyacrylic acid, tartaric acid .
• the functionalized elastomer introduced may include an antioxidant which has been added at the end of synthesis of the functionalized elastomer.
• the antioxidant added at the end of synthesis of the functionalized elastomer is any antioxidant known to be effective in preventing aging of the elastomers attributable to the action of oxygen.
• PPD para-phenylenediamine derivatives
• PPDA para-phenylenediamine derivatives
• N-1,3-dimethylbutyl-N ' para-phenylenediamine derivatives
• phenyl-p-phenylenediamine (more commonly known by the abbreviated term "6-PPD"), N-isopropyl-N'-phenyl-p-phenylenediamine (abbreviated as "1-PPD”), phenylcyclohexyl- p-phenylenediamine, N, N'-di (1,4-dimethylpentyl) -p-phenylenediamine, N, N'-diaryl-p-phenylenediamine (“DTPD”), diaryl- p-phenylenediamine (“DAPD”), 2,4,6-tris- (N-1,4-dimethylpentyl-p-phenylenediamino) -1,3,5-triazine, and mixtures of such diamines.
• 6-PPD N-isopropyl-N'-phenyl-p-phenylenediamine
• 1-PPD N-isopropyl-N'
• diphenylamines or substituted triphenylamines as described for example in the applications WO 2007/121936, WO 2008/055683 and WO2009 / 138460, in particular 4,4'-bis (isopropylamino) -triphenylamine, 4, 4'-bis (1,3-dimethylbutylamino) triphenylamine, 4,4'-bis (1,4-dimethylpentylamino) triphenylamine, 4,4 ', 4 "-tris (1,3-dimethylbutylamino) triphenylamine 4,4 ', 4 "-tris (1,4-dimethylpentylamino) triphenylamine.
• dialkylthiodipropionates or else phenolic antioxidants, in particular of the family of 2,2'-methylene-bis [4-alkyl (C 1 -C 6) alkyl-6-alkyl (C 1 -C 5) - 2) phenols, as described in particular in the application WO 99/02590.
• the antioxidant is selected from the group consisting of substituted p-phenylenediamines, substituted diphenylamines, substituted triphenylamines, and mixtures of such compounds; more preferably still, the antioxidant is selected from the group consisting of substituted p-phenylenediamines and mixtures of such diamines.
• antioxidant may refer to both a single antioxidant compound or a mixture of several antioxidant compounds.
• the process according to the invention uses at least one functionalized diene elastomer.
• diene elastomers before functionalization and then at least one method adapted to functionalize these elastomers. Diene elastomer, before functionalization:
• diene elastomer any polymer derived at least in part (i.e., a homopolymer or a copolymer) from monomers dienes (monomers bearing two carbon-carbon double bonds, conjugated or not).
• dienes monomers bearing two carbon-carbon double bonds, conjugated or not.
• the term "diene elastomer” that may be used in the invention is more particularly understood to mean a diene elastomer corresponding to one of the following categories:
• Suitable conjugated diene monomers for the synthesis of elastomers include butadiene-1,3 (hereinafter referred to as butadiene), 2-methyl-1,3-butadiene, 2,3-di (lower alkyl) and C 1 -C 5 ) - 1,3-butadienes such as for example 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl 1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene.
• diene monomer suitable for elastomeric synthesis mention may be made of 1,4-pentadiene, 1,4-hexadiene, ethylidene norbornene and dicyclopentadiene;
• ethylenically unsaturated monomers capable of intervening in the copolymerization with one or more diene monomers, conjugated or otherwise, to synthesize the elastomers mention may be made of:
• vinylaromatic compounds having 8 to 20 carbon atoms for example styrene, ortho-, meta-, para-methylstyrene, the commercial mixture vinylmesitylene, divinylbenzene, vinylnaphthalene;
• monoolefins such as, for example, ethylene and alpha-olefins, especially propylene or isobutene;
• the diene polymer (s) used in the invention are very particularly chosen from the group of diene polymers consisting of polybutadienes (abbreviated as "BR"), synthetic polyisoprenes (IR) and natural rubber (NR). ), butadiene copolymers, isoprene copolymers, ethylene and diene copolymers and mixtures of these polymers.
• BR polybutadienes
• IR synthetic polyisoprenes
• NR natural rubber
• Such copolymers are more preferably selected from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), isoprene-copolymers butadiene-styrene (SBIR), butyl halogenated or non-halogenated rubbers, and copolymers of ethylene and butadiene (EBR).
• SBR butadiene-styrene copolymers
• BIR isoprene-butadiene copolymers
• SIR isoprene-styrene copolymers
• SBIR isoprene-copolymers butadiene-styrene
• EBR ethylene and butadiene
• Functions capable of initiating a ring-opening polymerization of lactide are more particularly hydroxyl-OH or primary amine -NH 2 functions .
• the diene elastomers functionalized with one or two terminal groups (aux) may be prepared by various methods known to those skilled in the art, in particular by functional initiation, by termination reaction with a functionalizing agent or by coupling.
• a process for the preparation of a diene elastomer functionalized with one or two terminal amine groups is described, for example, in Schulz et al., Journal of Polymer Science, Vol. 15, 2401-2410 (1977).
• the diene elastomer functionalized with several pendant groups may be prepared by various methods known to those skilled in the art, in particular by grafting.
• the diene elastomer functionalized with nucleophilic groups along the main chain can be functionalized during a step of functionalization of the main chain of the elastomer by various techniques, for example by radical reaction, by hydrosilylation, by oxidation of the unsaturation followed by hydrogenation.
• This functionalization makes it possible to obtain a polymer functionalized with nucleophilic groups, advantageously primary amine or alcohol.
• the diene elastomer may be functionalized by radical reaction according to the method described in application WO 2014/095925.
• the number-average molar mass, Mn, of the functionalized diene elastomer is greater than 40,000 g / mol.
• the diene elastomer is functionalized by two terminal groups.
• the number-average molar mass, Mn, of the diene elastomer advantageously varies from more than 40,000 g / mol to 250,000 g / mol, more preferably from 50,000 g / mol to 200,000 g / mol.
• the diene elastomer is functionalized by several pendant groups distributed along the trunk, at least one of which is not terminal.
• the number-average molar mass, Mn, of the diene elastomer advantageously varies from 100,000 g / mol to 500,000 g / mol.
• the diene elastomer is functionalized by a terminal group.
• the number-average molar mass, Mn, of the diene elastomer advantageously varies from more than 40,000 g / mol to 150,000 g / mol.
• Copolymers obtained by the process according to the invention:
• the copolymers obtained by the process according to the invention have properties of a thermoplastic elastomer, namely elastic properties and a capacity to melt and harden, reversibly, under the action of heat, rigid blocks.
• the weight percentage of polylactide is between 10% and 45% by weight, advantageously up to 40% by weight, and even more advantageously from 15% to 40% by weight.
• the diene elastomer / polylactide copolymer obtained is a triblock, of PLA-diene elastomer-PLA structure, of number-average molar mass, Mn, ranging from 50,000 g / mol. at 300,000 g / mol.
• the diene elastomer / polylactide copolymer obtained is a comb copolymer having a diene elastomer trunk and pendant PLA blocks distributed along the trunk of average molar mass, Mn, ranging from 100 000 g / mol to 600,000 g / mol.
• the diene elastomer / polylactide copolymer obtained is a di-block of average molar mass, Mn, ranging from 50,000 g / mol to 200,000 g / mol.
• Mn average molar mass
• the melting temperature of the PLA block advantageously ranges from 100 ° C to 230 ° C, more preferably from 150 ° C to 210 ° C.
• copolymers obtained by the process according to the invention in particular the triblock or the comb copolymer, withstand large deformations before rupture but may flow at a temperature above the melting temperature of the PLA block or blocks.
• the copolymer according to the invention in particular tri-block or comb copolymer, has an elongation at break of at least 150% as measured by the method described before the examples, paragraph "mechanical tests”.
• the copolymer may be used in a composition, the composition is advantageously a rubber composition, in particular a composition usable in the manufacture of a tire.
• the copolymer according to the invention is particularly useful for the preparation of tread compositions.
• the copolymer according to the invention makes it possible to manufacture a tread making it possible to obtain a very good compromise of the performance in adhesion and in rolling resistance.
• the molar masses are determined by steric exclusion chromatography (SEC) in polystyrene equivalent.
• the SEC makes it possible to separate the macromolecules in solution according to their size through columns filled with a porous gel.
• the macromolecules are separated according to their hydrodynamic volume, the larger ones being eluted first.
• the SEC allows to apprehend the distribution of the molar masses of a polymer.
• Mn various average molar masses
• Mw weight
• Ip polymolecularity index or polydispersity
• MOORE Mw / Mn
• the apparatus used is an "Agilent 1200" chromatograph.
• the eluting solvent is chloroform.
• the flow rate is 0.7 ml / min, the system temperature 35 ° C and the analysis time 90 min.
• a set of four Waters columns in series, Styragel HMW7, Styragel HMW6E and two Styragel HT6E is used.
• the injected volume of the solution of the polymer sample is 100 ⁇ l.
• the detector is a differential refractometer is a Waters 2010 and the chromatographic data mining software is the "Waters Empower" system.
• the average molar masses calculated relate to a calibration curve made from commercial standard polystyrene "PSS ReadyCal Kit".
• b Molar mass of the elastomeric diene / polylactide copolymer It is determined by steric exclusion chromatography (SEC) in polystyrene equivalent.
• SEC steric exclusion chromatography
• Preparation of the polymer There is no particular treatment of the polymer sample before analysis. This is simply solubilized in chloroform at a concentration of about 2 g / l. Then the solution is filtered on 0.45 ⁇ porosity filter before injection.
• the determinations of PLA levels in the triblock or comb copolymers and the microstructures of the diene elastomers within the copolymer are carried out by NMR analysis.
• the samples (approximately 20 mg) are solubilized in 1 ml of CDCl 3 and introduced into a 5 mm NMR tube.
• the spectra are recorded on a Bruker Avance III HD 500 MHz spectrometer equipped with a BBFO 1 HX 5mm Z_GRD probe.
• the spectra are calibrated on the signal CISC 3 to 7.20ppm in 1 H.
• the melting temperatures, melting enthalpies and glass transition temperatures Tg of the polymers are measured by means of a differential scanning calorimeter.
• the SBR / PLA (control) copolymers or mixture obtained were analyzed by DSC on a DSC Q200 device of the TA instrument type under the following operating conditions: 1st heating from 20 ° C. to 200 ° C. (10 ° C./min) cooling 200 ° C to -70 ° C (10 ° C / min), 2nd heating from -70 ° C to 200 ° C (10 ° C / min). 4. Mechanical tests
• the tensile stress (MPa), the elongation at break (%) are measured by tensile tests according to the international standard ASTM D638 (year 2002). All these tensile measurements are performed under the normal conditions of temperature (23 ⁇ 2 ° C) and humidity (50 ⁇ 5% relative humidity), according to the international standard ASTM D638 (year 2002). The measurements are made on type V specimens at a pulling speed of 50 mm / min on a Lloyd LR 10k machine. The deformation is measured by following the displacement of the crossbar.
• DMA Dynamic Mechanical Analysis
• the linear viscoelastic properties of these materials are measured by low strain (0.1%) sinusoidal elongation.
• the measurements are carried out on a dynamic mechanical analyzer (DMA) TA instrument (DMA800) with deformation imposed on specimens of rectangular shape and dimensions (mm): 25 x 5 x 0.5.
• the samples are molded at 183 ° C for 5 minutes and then cut with a punch.
• PLA-SBR-PLA Triblock Copolymers Obtained by Polymerization of Lactide on a Difunctionalized Amine SBR in Reactive Extrusion Di-functionalized primary aromatic amine SBR (styrene-butadiene rubber) was tested.
• a non-functionalized Mn SBR is used which is higher to approach the Mn of the synthesized copolymers.
• the di-functionalized primary aromatic amine SBRs were synthesized according to the following protocol, detailed here for a di-functionalized SBR of 87,300 g / mol:
• a reactor of 30L in total are added successively: 1 1, 5L of methylcyclohexane (MCH), 1 L of 4-bromo-N, N-bis (trimethylsilyl) aniline (previously bubbled with nitrogen), 5.35L a solution of s-BuLi at 1, 4mol / L in cyclohexane and 0.35mol of tetramethylethylenediamine (TMED) previously purified on Al 2 0 3 .
• MCH methylcyclohexane
• 4-bromo-N, N-bis (trimethylsilyl) aniline previously bubbled with nitrogen
• 5.35L a solution of s-BuLi at 1, 4mol / L in cyclohexane and 0.35mol of tetramethylethylenediamine (TMED) previously purified on Al 2 0 3 .
• TMED tetramethylethylenediamine
• the deprotection conditions are as follows: 2 eq of HCI / amine for 48 h at 80 ° C. After the deprotection reaction is complete, the reaction medium is washed with raw water in order to extract the maximum amount of acid and to raise the pH of the aqueous phase to 7. A sodium hydroxide solution can be used to raise the pH above above 7 (0.5eq sodium hydroxide / HCl).
• microstructures and macrostructures of these functionalized SBRs are given in the following table:
• a DSM Xplore micro-extruder with a capacity of 15 g is used.
• the functionalized SBR obtained previously (8.4 g), previously dried, is incorporated in the micro-extruder, together with a mixture (lactide / Sn (oct) 2 / additives) contained in a bicoloured flask and previously prepared in a box. gloves.
• additives refers to triphenylphosphine (P (Ph) 3 ) and / or U626 (antioxidant, ULTRANOX®626, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite).
• the temperature of the mixture is maintained at 170 ° C.
• the functionalized SBR is previously dried for 12 hours under vacuum at 60 ° C., until a residual water content of less than 300 ppm.
• the molar masses of the materials obtained are greater than that of the starting functional SBR.
• the increase in molar masses is all the more important as the initial lactide fraction is high.
• the main bulk of the SEC curve is in the same position as that of the starting elastomer. A small secondary mass is observed, consistent with obtaining PLA homopolymer of average molar mass close to 9,500 g / mol.
• PLA homopolymer determined by SEC in PS equivalent.
• the vertical force exerted on the sleeves by the extruded material begins to increase as soon as the catalytic system is introduced (arrow towards 10 min in FIG. 2A, towards 2 min in FIG. 2B). Then the force reaches a maximum which corresponds to the end of the polymerization (arrow towards 10 min in Figure 2A, 8 min in Figure 2B).
• control mixture has no mechanical strength.
• Example 2 SBR-g-PLA comb copolymers obtained by polymerization of lactide on a functional SBR functional alcohol in reactive extrusion Comb copolymers (SBR-g-PLA) were synthesized by polymerization of lactide, in the presence of a functional SBR possessing mercapto - 1 - butanol groups grafted along the chain.
• This functional SBR is prepared by following the procedure below.
• the functionalized elastomer is then resolubilized, and 0.4% by weight, based on the weight of the elastomer, of a mixture Irganox®2246 / 6PPD (80/20) is added.
• the functionalized elastomer is then dried under vacuum at 50.degree.
• the grafting obtained is 1.3% mol, and the mass yield obtained is 82%.
• microstructures and macrostructures of this functionalized SBR are given in the following table:
• the di-functionalized primary aromatic amine SBR was synthesized following the protocol given in Example 1.
• microstructures and macrostructures of this di-functionalized SBR are given in the following table:
• This SBR is dried for 12 hours at 60 ° C. under air.
• the lactide is introduced into the sleeve No. 1, the functionalized SBR (mixed with 2% by weight of EVA) in the sleeve 2 and the catalytic system in the sleeve 3.
• the weight ratio SBR / lactide is 60/40.
• the molar ratio [LA / Sn (oct) 2 ] is 700 and P (Ph) 3 is added in an amount allowing to have a molar ratio (Sn / P) of 1/1.

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