EP3652222A1

EP3652222A1 - Method for functionalising a stereoregular polydiene

Info

Publication number: EP3652222A1
Application number: EP18738333.6A
Authority: EP
Inventors: Marc Visseaux; Philippe ZINCK; Sébastien Georges; Yohan CHAMPOURET
Original assignee: Centre National de la Recherche Scientifique CNRS; Universite Lille 2 Droit et Sante; Ecole Centrale de Lille; Ecole Nationale Superieure de Chimie de Lillie ENSCL; Universite dArtois
Current assignee: Centre National de la Recherche Scientifique CNRS; Universite Lille 2 Droit et Sante; Ecole Centrale de Lille; Ecole Nationale Superieure de Chimie de Lillie ENSCL; Universite dArtois
Priority date: 2017-07-11
Filing date: 2018-07-11
Publication date: 2020-05-20
Also published as: FR3068973A1; US11634519B2; FR3068973B1; US20200157259A1; WO2019012009A1

Abstract

The present invention relates to a method for the end functionalisation of trans-1,4 stereoregular polydiene chains obtained by the coordination catalysis polymerisation of at least one conjugated diene monomer. It also relates to a polydiene having a trans-1,4 chain formation rate of at least 85%, preferably at least 90%, and an end functionalisation rate higher than 70%, preferably higher than 80%, and more preferably higher than 90%.

Description

METHOD FOR FUNCTIONALIZATION OF STEREO-REGULAR POLYDIENE

The present invention mainly relates to a method useful for the terminal functionalization of stereo-regular polydiene chains of trans-1,4 configuration.

The polydienes essentially derive from the homopolymerization or co-polymerization of conjugated dienes. These polymerizations are therefore, depending on their conditions of implementation and when the polymerization takes place with a 1,4-regioselectivity, capable of generating polydiene chains having double bonds of cis-1,4 and / or trans-configuration. 1.4. However, stereo-regularity has beneficial consequences on the properties of materials derived from these polydienes, and its control is therefore of great interest to manufacturers. Thus, it is advantageous to have a mode of synthesis of so-called stereo-regular polydienes, that is to say the micro structure of which is controlled to have a significant preponderance in one or the other of the cis-configurations. 1.4 or trans-1,4, and in particular of trans-1,4 configuration.

Another center of interest for the formulators of these polydienes is their functionalization at the end of chains. The presence of terminal functional groups indeed has the advantage of making possible adjustments of their physicochemical properties in particular in terms of adhesion, printability or affinity with other compounds but also to allow the development of polymers of more elaborate architecture. Of course, the provision of a synthesis mode to satisfy both of these requirements at once would be particularly interesting on an industrial level.

Methods of synthesis of polydienes whose stereo-regularity is controlled have already been proposed. In particular, 1,4-trans -polydienes can be synthesized by coordination catalysis polymerization using rare earth catalysts. However, no functionalization is jointly considered (Terrier et al., Journal of Polymer Science Part A, 2007, 45 (12), pp. 2400-2409). Moreover, different modes of functionalization of polydienes have been described. For the most part, functionalization has been considered with regard to diene polymers obtained by anionic or radical polymerization (Heurtefeu et al., Polymer Chemistry, 2010, 1, pp.1078-1085). However, the anionic and radical polymerizations do not make it possible to effectively control the stereo-regularity of the polydiene formed. Methods for functionalizing 1,4-polyisoprenes have also been described in batch processes (Brush et al., Journal of Applied Polymer Science, 78, pp. 146-1477). Discontinuous processes are, however, not very advantageous on the industrial level because they are insufficiently productive and economical.

Finally, the synthesis of cis-1,4 regular stereo-polyisoprene and polybutadiene by coordination polymerization followed by a post-polymerization reaction by means of a functionalization agent has already been envisaged, in particular in document WO 2015 / 101477. However, such a method can not be transposed to the synthesis of trans-1,4 functionalized stereo-regular polydienes.

Indeed, the synthesis of polydienes by coordination catalysis using a catalytic system based on rare earth, in particular Nd (BH ₄ ) 3 (THF) 3, and comprising an excess of an organometallic compound based on of a metal belonging to the ^2nd column or the I3 ^th column of the periodic table has already been described in WO 2010/139449. However, in this case, the requirement of trans-1,4 stereo-regularity is not respected.

There remains therefore a need for an efficient method for accessing functionalised polydienes and trans-1.4 stereoregularity rigorously controlled. In particular, there is a need to access such polymers with a limited number of reaction steps for the sake of competitiveness for production on an industrial scale.

To these requirements is added that of a more ecological interest. It is now a matter of constant concern for manufacturers to favor, where possible, biosourced raw materials. In the present case, terpenes are natural diene compounds which it would be advantageous to be able to consider as precursors of stereo-regular and functionalized diene polymers as referred to according to the invention. The present invention is precisely to meet all these expectations.

Thus, according to a first aspect, the present invention relates to a method useful for the terminal functionalization of trans-1,4 stereo-regular polydienic chains obtained by coordination catalysis polymerization of at least one conjugated diene monomer, characterized in that said method comprises at least the steps of:

a) having a medium containing stereo-regular diene polymer chains formed in situ by coordination catalyzed polymerization of at least one conjugated diene monomer in the presence of an effective catalytic system to promote a stereo-regular trans-polymerization; 1.4 of said monomer,

b) introducing, in contact with said stereo-regular channels, an excessive amount of at least one metal transfer agent and maintain this contact under conditions conducive to their transfer to said metal transfer agent, and

c) contacting the stereo-regular chains, transferred at said metal transfer agent, with at least one functionalizing agent and maintaining this contact under conditions that are effective for the formation of a trans-1 stereo-regular diene polymer, 4 functionalized in at least one of its terminal ends. FIG. 1 schematizes a process for synthesizing a trans-stereoregular polydiene according to the invention, implementing at least one conjugated diene monomer, a rare earth catalyst and benzophenone as functionalization agent.

Advantageously, the polydiene obtained according to the process defined above has a degree of terminal functionalization greater than 70%, preferably greater than 80%, more preferably greater than 90%, or even greater than 95%.

According to a preferred variant, the coordination catalyzed polymerization is a chain transfer coordinative polymerization and the catalytic system comprises at least one metal catalyst and an alkylating agent, preferably in a molar ratio of alkylating agent to catalyst less than 5. , preferably less than 3 and more preferably equal to 1. Unexpectedly, the inventors have indeed found that it is possible to efficiently carry out the terminal functionalization of polydiene chains in the continuity of their preparation by polymerization, subject to considering a specific mode of polymerization, in this case by coordination catalysis, and the presence of a metal transfer agent in an amount also determined. In addition, the implementation of such a process does not require the implementation of an excess of alkylating agent while allowing a maximum alkylation rate.

Advantageously, the polymerization steps of stereo-regular diene polymer chains and terminal functionalization can be carried out in a single reaction medium ("one pot") subject to also consider a chain transfer step.

To the inventors' knowledge, this combination of steps in the same reaction medium has never been considered before to access polydienes whose trans-1,4 stereo-regularity and terminal functionalization are strictly controlled and therefore confers on the process according to the invention a reproducible aspect particularly interesting on the industrial level.

This method is also particularly advantageous in that it makes it possible to dispense with a subsequent post-reaction stage of the polymer on a functionalization agent.

Advantageously, steps a) to c) of the process according to the invention are carried out continuously. This embodiment is particularly interesting in that it allows a simpler and more economical implementation of the process, especially since it is feasible in a single reactor. Furthermore, the inventors have also found that a process according to the invention is suitable for the preparation of trans-1,4 stereo-regular polydienes functionalized from dienes derived from biomass, such as certain terpenes, in particular myrcene, ocimene, farnesene and mixtures thereof.

This embodiment is particularly interesting both industrially and environmentally. According to a preferred embodiment of the invention, the diene polymer chains considered in step a) have a trans-1,4 stereo-regularity at a rate of more than 85%, preferably more than 90%, more preferably more than 95%.

Such trans-1,4 stereo-regular diene polymers have the particularity of being crystalline at room temperature and thus allow stiffness to be provided in the materials thus formed.

The choice of the catalytic system is decisive for promoting this trans-1,4 stereorregularity.

Thus, according to a preferred variant, the catalytic system of step a) comprises a rare earth catalyst / alkylating agent pair chosen from Ln (BH ₄ ) ₃ (THF) ₃ / BEM, C ₅ Me ₅ Ln (BH ₄ ) ₂ (THF) ₂ / BEM, LnCl ₃ (THF) ₃ / BEM.

Advantageously, it is a Nd (BH ₄ ) ₃ (THF) ₃ catalyst combined with a butylethylmagnesium alkylating agent in a molar ratio relative to neodymium of less than 5.

According to an advantageous variant embodiment, the diene polymer chains considered in step a) are polyisoprene chains having a trans-1,4 stereoregularity, the catalytic system implemented in step a) comprises an Nd (BH ₄ ) catalyst. ) ₃ (THF) ₃ combined with a butylethylmagnesium alkylating agent in a molar ratio relative to neodymium equal to 1 and the metal chain transfer agent used in step b) is butylethylmagnesium, in a molar ratio relative to neodymium at least equal to 5 or n-butyllithium in a molar ratio relative to neodymium at least equal to 5, preferably at least 10, or methyllithium in a molar ratio relative to neodymium of at least 5.

According to another of its aspects, the present invention relates to a polydiene having a trans-1,4 linkage ratio of at least 85%, preferably at least 90%, and a degree of terminal functionalization greater than 70%. preferably greater than 80%, more preferably greater than 90%, or even greater than 95%. FIGURES

Figure 1: Schematic diagram showing the synthesis of a trans-stereoregular polydiene, from conjugated diene monomers, and its functionalization at the end of the chain with a benzophenone functionalization agent, by a process according to the invention.

2: Photos showing a drop of water deposited on a substrate coated with a polyisoprene iraws-stereo-regular film functionalized with a polar functionalization agent according to the invention (A) and on a substrate covered with a film in non-functionalized trans-stereo-regular polyisoprene (B).

DETAILED DESCRIPTION OF THE INVENTION The term "conjugated diene monomer" according to the invention is understood to mean a hydrocarbon containing at least two conjugated double bonds.

By "stereo-regular polydiene" according to the invention is meant a polydiene having a trans-1,4 linkage ratio of at least 85%, preferably at least 90%, more preferably at least 95%.

By "functionalized polydiene" according to the invention is meant a polydiene whose terminal functionalization rate is greater than 70%, preferably greater than 80%, more preferably greater than 90%, or even greater than 95%.

By "terminal functionalization rate" according to the invention is meant the molar amount of terminal ends of functionalized chains referred to the molar amount of terminal chain ends in the absence of functionalization.

By "terminal end" according to the invention is meant the free ends of a polydiene chain.

Process according to the invention

The first step of the process imposes to have a medium containing stereo-regular polydienes that is to say the rate of double chaining trans-1,4 bonds is at least 85%, preferably at least 90%, more preferably at least 95%.

Advantageously, these chains are generated in situ in this medium by coordination catalyzed polymerization of at least one conjugated diene monomer in the presence of an effective catalytic system to promote stereoregular trans-1,4 polymerization of said monomer. a) Coordination catalysis polymerization step

Coordination catalysis polymerization is a type of chain polymerization in which initiation occurs through a complex coordination catalyst and propagation occurs at an active center which is an organometallic complex between the monomer and the metal. that is, said organometallic complex comprising at least one metal-carbon bond.

Such a step of polymerization by coordination catalysis uses at least one conjugated diene monomer. A process according to the invention thus allows the synthesis of homo- and diene copolymers.

monomers

In general, all conjugated dienes conventionally considered for preparing polydienes can be considered in the process of the invention.

By way of illustration and not limitation of these conjugated dienes may be mentioned 1,3-butadiene, 2,3-di (C 1 -C 5 alkyl) 1,3-butadienes, substituted 1,3-butadienes, such as isoprene, di-, tri- or tetra-1,3-pentadienes, 1,3-hexadiene, 2,4-hexadiene, terpenes or any other conjugated diene comprising between 4 and 8 carbon atoms and mixtures thereof .

Preferably, the monomer (s) used in a process according to the invention may be chosen from terpenes which have the advantage of being readily available raw materials used in various industrial applications. In addition, these compounds can be directly extracted from plants and are therefore generally biobased. The preferred terpenes are myrcene, ocimene, farnesene and mixtures thereof, more preferably myrcene.

Terpenes can also be co-polymerized with any other conjugated diene, preferably with isoprene.

Preferably, the monomer (s) is chosen from isoprene, myrcene and their mixtures.

This diene monomer (s) may also be co-polymerized with other monomers commonly used in the polymer field, for example styrene, methylstyrene, divinylbenzene, ethylene and alpha-olefins. , so as to form statistical or block chains.

Advantageously, a process according to the invention uses at least one monomer and at least one catalyst in a molar ratio of monomer (s) relative to the catalyst ranging from 20 to 2000, preferably from 20 to 1000, more preferably from 50 to 200.

Catalyst

As stated above, it is possible, through the choice of the catalyst, to direct the polymerization towards a trans-1.4 stereo-regularity according to the invention.

The choice of the catalyst is clearly within the skill of those skilled in the art, in order to guide the polymerization to a trans-1.4 stereo-regularity according to the invention.

Thus, the catalyst considered according to the invention can be a rare earth catalyst of formula

(CpR) _m RE (A) ₃ _m (B) _n ,

in which :

RE is a rare earth metal, preferably a Lanthanide;

each unit A, identical or different, is independently selected from halides, carboxylates, organophosphates, alkoxides, phenates, amides, alkyls, alkoxy, allyls, borohydrides or their mono- or di-substituted derivatives ;

each B, identical or different, represents a solvent molecule complexed on the rare earth metal; CpR represents a cyclopentadienyl of the formula CsH ₅ _to R _a , with an integer between 0 and 5, or one of its derivatives,

m represents 0 or 1; and

n is an integer from 0 to 3.

Preferably A is a borohydride.

Preferably m is 0 and n is 3.

A preferred lanthanide according to the invention is neodymium.

The catalyst is advantageously chosen from compounds of formula Ln (BH ₄ ) ₃ (THF) ₃ , CpLn (BH ₄ ) ₂ (THF) ₂ , such as C ₅ Me ₅ Ln (BH ₄ ) ₂ (THF) ₂ , and LnCl ₃ (THF) ₃ .

A preferred catalyst according to the invention is the compound of formula

Nd (BH ₄ ) ₃ (THF) ₃ .

The catalysts considered according to the invention can be prepared by any method known to those skilled in the art. In particular, the rare earth salts can be prepared according to the methods described in WO 02/38636.

Other synthetic routes are described, in particular in the document S Cendrowski-Guillaume, M. Nierlich, M. Lance, M. Ephritikhine, Organometallics, 1998, 17, 786. For example, the catalyst Ln (BH ₄ ) ₃ ( THF) ₃ can be synthesized by reaction of lanthanide trichloride with excess sodium borohydride (20%) in THF.

According to a particularly advantageous embodiment of the invention, the stereo-regular diene polymer chains considered according to the invention are formed in situ by coordinative polymerization with chain transfer.

The coordinative polymerization with chain transfer is a coordination polymerization allowing the growth of several chains per unit of catalyst. This process involves an equilibrium between the growing chains on the catalyst metal and the chains carrying a metal transfer agent at the terminal end of the chain.

Thus, this embodiment is advantageous in that it allows the growth of several polymer chains from a catalyst molecule, and thus the use of a reduced amount of catalyst.

According to this embodiment of the invention, the catalytic system comprises a metal catalyst as defined above and an alkylating agent. Alkylating agent

The alkylating agent considered in the context of the present invention may be chosen from compounds of formula:

(MR _q X _p ) _r

in which :

M is selected from alkali metals, alkaline earth metals, transition metals or metals of column 13 of the periodic table of elements;

each R, identical or different, independently represents a grouping

(C1-C10) linear or branched alkyl, optionally having one or more unsaturations, or each R forming with the metal a C3-C10 ring;

X represents a halogen atom;

p is an integer equal to 0, 1 or 2;

q is an integer defined according to the valence of the metal in question; and r is an integer greater than or equal to 1.

Preferably M is an alkaline earth metal, such as magnesium, or aluminum.

Preferably, X is a chlorine atom, especially when M is an aluminum.

The alkylating agent may thus be chosen from alkyllithiums, dialkylmagnesiums, trialkylaluminiums, dialkylzincics, dialkylhalides or organomagnesiums.

Advantageously, the alkylating agent is chosen from dialkylmagnesians, alkyllithiens and trialkylaluminiums, preferably it is butylethylmagnesium.

The alkylating agent considered according to the invention can also be difunctional. Thus, the alkylating agent can be chosen from compounds of formula (MgIsoprenyl) _n , (MgButadienyl) _n , (MgMyrcenyl) _n or be a cyclic magnesium such as magnesiacyclopentane Mg (CH ₂ ) s. A di-functional alkylating agent according to this embodiment makes it possible to promote functionalization at the two ends of each stereo-regular polydiene chain according to the invention. Thus, this embodiment allows the synthesis of telechelic stereo-regular polydienes.

The alkylating agent considered according to the invention can be synthesized by any method known to those skilled in the art. For example, when the alkylating agent is di-functional, it can be synthesized according to the method described in H. Yasuda and ah, Macromolecules, 1978, 11, 586. According to a particular embodiment of the invention, the Catalyst system comprises a rare earth catalyst of formula (CpR) _m RE (A) ₃ _m (B) _n in which CpR, RE, A, B, m and n are as defined above, in combination with an agent alkylating formula (MR _q X _p) _r wherein M, R, X, q, p and r are as defined above.

According to a particular embodiment of the invention, the catalytic system considered in step a) comprises a rare earth catalyst / alkylating agent pair chosen from Ln (BH ₄ ) ₃ (THF) ₃ / BEM, CpRLn (BH ₄ ) ₂ (THF) ₂ / BEM, such as

C ₅ Me ₅ Ln (BH ₄ ) ₂ (THF) ₂ / BEM, LnCl ₃ (THF) ₃ / BEM and preferably comprises a catalyst Nd (BH ₄ ) ₃ (THF) ₃ and a alkylating agent butylethylmagnesium in a molar ratio compared to neodymium less than 5.

In particular, the diene polymer chains considered in step a) are polyisoprene chains and step a) uses an Nd (BH ₄ ) ₃ (THF) ₃ catalyst and a butylethylmagnesium alkylating agent in a molar ratio relative to with neodymium equal to 1 as catalytic system and step b) uses butylethylmagnesium, in a molar ratio relative to neodymium at least equal to 5 or n-butyllithium in a molar ratio relative to neodymium at least equal to 5, preferably at least 10, or methyllithium in a molar ratio relative to neodymium of at least 5, as a metal chain transfer agent. In a particularly advantageous manner, the catalytic system according to the invention comprises an alkylating agent in a molar ratio of less than 5, relative to the metal catalyst considered for the polymerization in situ. Preferably, the report The molar ratio of the alkylating agent to the metal catalyst is less than 3 and more preferably 1.

The operating conditions considered for the polymerization are usual conditions and their adjustment is clearly within the competence of those skilled in the art.

The polymerization, in particular coordination with chain transfer, can be carried out in a solvent medium under an inert atmosphere, for example under argon and at a temperature ranging from 30 ° C. to 100 ° C., preferably from 40 ° C. to 60 ° C. and be completed within at least 60 minutes, preferably at least 2 hours, for example at least 4 hours.

In particular, the duration of the polymerization reaction of at least 60 minutes, preferably at least 2 hours, for example at least 4 hours, ensures complete conversion to monomer.

Indeed, trans-1,4 stereo-regular polydiene corresponds to the thermodynamic isomer with respect to the cis-1,4 stereo-regular polydiene which is the kinetic isomer. Thus, a longer polymerization reaction time makes it possible to ensure a complete conversion to trans-1,4 stereo-regular polydiene.

Advantageously, steps a) to c) of the process are carried out in a volatile organic solvent, in particular chosen from toluene, cyclohexane, methylcyclohexane, heptane, mesitylene, cumene and their mixtures, preferably toluene.

As is apparent from the foregoing, the method according to the invention has the advantage of being feasible continuously and in a single receptacle or reactor and this thanks to the implementation of the polydienic chains said "transferred" to an agent of metal transfer for the functionalization step.

According to a preferred embodiment, the catalytic system according to the invention comprises a magnesium, especially a dialkylmagnesian, as alkylating agent. b) Chain transfer stage

During this chain transfer step, the terminal ends of the stereo-regular diene polymer are transferred from the catalyst metal to the level of a metal transfer agent. This transfer results in the binding of the transfer agent to the terminal ends of the stereo-regular channels.

This chain transfer step therefore involves the contacting of stereo-regular chains resulting from the polymerization by coordination catalysis, in the presence of an excessive amount of at least one metal transfer agent.

The transfer at the level of the polydiene chains from the catalyst to the metal transfer agent is advantageous in that it makes it possible to achieve very high terminal functionalization levels. Indeed, the reactivity of the ends of the polydienes linked to a transfer agent according to the invention, vis-à-vis the functionalizing agent, is greater than the reactivity of said ends when they are linked to the catalyst.

Metallic transfer agent

In particular, the amount of metal transfer agent is adjusted so that the transfer equilibrium is totally shifted towards the polydiene-metal species formation of the transfer agent, and the molar proportion of terminal ends of chains transferred. at the level of the transfer agent with respect to the total molar amount of terminal chain ends is thus between 70% and 100%, preferably greater than 90%.

An excessive amount of metal transfer agent corresponds to a higher transfer agent content than that of the polymerization catalyst.

In particular, the molar ratio of alkyl from the metal transfer agent to the catalyst is at least equal to 5, and preferably at least equal to

10 or at least equal to 20.

Preferably, the metal transfer agent considered according to the invention is chosen from compounds of formula:

M'R _X X _S

in which :

M 'is an alkali metal, an alkaline earth metal, or a metal of column 13 of the periodic table of elements;

each R is independently a linear or branched C 1 -C 10 alkyl group, optionally having one or more unsaturations; X represents a halogen atom;

s is an integer equal to 0 or 1; and

x is an integer defined according to the valence of the metal considered. Preferably, s is 0.

In a particularly advantageous manner, the metal transfer agent considered according to the invention is chosen from dialkylmagnesians, alkyl lithium and trialkylaluminums, preferably from butylethylmagnesium, n-butyllithium, methyllithium, triisobutylaluminium and triethylaluminium.

In the process according to the invention, the contact between the stereo-regular chains resulting from the coordination catalysis polymerization and the excessive quantity of at least one metal transfer agent is maintained under conditions conducive to their transfer to said agent. metal transfer.

The optimization of the duration of maintaining the contact and the conditions conducive to the transfer is clearly within the skill of those skilled in the art in order to achieve the transfer of stereo-regular channels at the level of the metal transfer agent.

The contact considered in step b) can be advantageously maintained for at least 60 minutes, preferably for at least 2 hours, for example at least 4 hours, following the introduction of the excessive amount of metal transfer agent.

Similarly, step b) is advantageously carried out at a temperature between 0 ° C and 100 ° C, preferably between 20 ° C and 80 ° C, more preferably between 40 ° C and 60 ° C.

In a particularly advantageous manner, step b) according to the invention is carried out at a temperature of between 0 ° C. and 100 ° C., preferably between 20 ° C. and 80 ° C., more preferably between 40 ° C. and 60 ° C. and maintained for at least 60 minutes, preferably at least 2 hours, for example at least 4 hours.

According to a particular embodiment of the invention, the step b) of transfer at the level of the metal transfer agent takes place consecutively with step a) of catalytic coordination polymerization of at least one conjugated diene monomer .

This embodiment is particularly illustrated by Examples 5 to 10 below. This embodiment is particularly advantageous in that it makes it possible to obtain particularly high levels of functionalization. According to this embodiment, the metal transfer agent is added after the polymerization step a). The metal transfer agent may be identical to or different from the alkylating agent of the catalytic system as defined above.

In particular, the metal transfer agent may be identical to the alkylating agent of the catalytic system as defined above. Preferably, according to this embodiment, the metal transfer agent is chosen from dialkylmagnesians, and is especially butylethylmagnesium.

According to one embodiment, the alkylating agent of the catalytic system is chosen from dialkylmagnesians, and is especially butylethylmagnesium, and the metal transfer agent is also chosen from dialkylmagnesians, and is especially butylethylmagnesium.

In particular, the metal transfer agent may be different from the alkylating agent of the catalytic system as defined above. Preferably, according to this embodiment, the metal transfer agent is chosen from alkyllithiens and more particularly from n-butyllithium or methyllithium.

According to one embodiment, the alkylating agent of the catalytic system is selected from dialkylmagnesians, and is especially butylethylmagnesium, and the metal transfer agent is also selected from alkyl lithium and more particularly from n-butyllithium or methyllithium.

Thus, the transfer agent is added in excess when the monomer conversion is maximum or complete, that is to say after a polymerization reaction time of at least 60 minutes, preferably at least 2 hours. for example at least 4 hours.

According to this embodiment, the metal transfer agent may be identical to or different from the alkylating agent defined above. In particular, the alkylating agent can be chosen from dialkylmagnesians, alkyl lithium, trialkylaluminums and compounds of formulas (MgIsoprenyl) _n , (MgButadienyl) _n and (MgMyrcenyl) _n, and the transfer agent can be chosen from dialkylmagnesians. alkyllithians and trialkylaluminums. Preferably, it is a pair alkylating agent / transfer agent butylethylmagnesium / butylethylmagnesium, butylethylmagnesium / n-butyllithium, butylethylmagnesium / methyllithium, (MgIsoprenyl) _n / n-butyllithium or

(MgIsoprenyl) _n / methyllithium. When it is identical to the alkylating agent considered during the polymerization step, contacting the polydiene chains with said metal transfer agent requires an adjustment of the amount of this transfer agent in the reactor to access the excess necessary for the good progress of the transfer reaction, carried out at the end of the polymerization considered in step a), that is to say when the conversion to monomer is maximum or complete. For this, it is advantageous to carry out the polymerization reaction considered in step a) for a period of at least 60 minutes, preferably at least 2 hours, for example at least 4 hours before adjusting the amount of agent. transfer.

Thus, advantageously according to this embodiment, the metal transfer agent is identical to the alkylating agent and step b) is carried out consecutively to step a).

According to another particular embodiment of the invention, the generation of "transferred" polydiene chains considered in step b) can be carried out simultaneously with the polymerization carried out in step a).

Thus, the transfer agent is added, in excess, from the beginning of the coordination catalysis polymerization of at least one conjugated diene monomer considered in step a).

This embodiment is particularly illustrated by Examples 3 and 4 below.

In particular, the metal transfer agent may be different from the alkylating agent of the catalytic system as defined above. Preferably, according to this embodiment, the metal transfer agent is chosen from trialkylaluminiums and more particularly is triethylaluminium.

According to one embodiment, the alkylating agent of the catalytic system is chosen from dialkylmagnesians, and is especially butylethylmagnesium, and the metal transfer agent is also chosen from trialkylaluminiums.

Thus, steps a) and b) can be carried out simultaneously and the metal transfer agent can be present during the polymerization of stereoregular chains. The reactor considered in step a) then contains growing chains on the catalyst metal, monomer not yet polymerized, polydiene chains transferred to the metal of the transfer agent and being transferred.

According to this embodiment, the metal transfer agent is different from the alkylating agent defined above. In particular, the alkylating agent is chosen from compounds of formula (MR _q X _p ) _r as defined above in which M represents a magnesium and the metal transfer agent is chosen from compounds of formula M'R _X X _S , wherein M 'is aluminum. Preferably, the alkylating agent is a trialkylmagnesian and the transfer agent is a trialkylaluminium, more preferably it is a pair alkylating agent / transfer agent butylethylmagnesium / triethylaluminum or butylethylaluminium / triisobutylaluminium.

Thus, advantageously according to this embodiment, the alkylating agent is introduced in excess from the beginning of the polymerization in situ, the alkylating agent is a dialkylmagnesian and the metal transfer agent is a trialkylaluminium.

This embodiment is particularly surprising since it is known that the presence of an organometallic compound based on a divalent or trivalent metal in excess from the beginning of the polymerization by coordination catalysis of conjugated dienes does not make it possible to achieve a desired trans-stereo stereo-regularity according to the present invention (WO2010 / 139449). c) Functionalisation stage

A method according to the invention comprises a step of contacting stereo-regular channels, transferred at the level of the metal transfer agent, with at least one functionalization agent.

To do this, a functionalizing agent is added to the reaction mixture comprising stereo-regular chains transferred to the level of the metal transfer agent.

This functionalization is preferably carried out following the carrying out of the transfer, in particular so as to obtain polydiene chains of the same size.

The functionalising agent may be any compound comprising a group capable of reacting on at least one of the anionic living ends linked to a metal of a stereo-regular chain. The choice of this functionalization agent is of course conditioned by the desired modification at the level of the polydiene chain. Trans-stereomeric polydienes are apolar polymers. The functionalization agent can thus be chosen to bring a polar character to the chain ends of the polydiene,

This choice is clearly within the skill of the skilled person.

In particular, the functionalizing agent may be chosen from carboxylic acid derivatives, ketones, aldehydes, esters, imidazolidinones, isocyanates, nitriles, epoxides, imines, amides, cyclic amines, siloxanes, phosphates, organo-sulfur compounds, dihalogens, carbamates, thiocarbamates, urea compounds, carbonates, lactones, carbon oxides and dioxygen.

Preferably, it is an electrophilic compound, more particularly chosen from benzophenone, 4- (N, N-dimethylamino) benzophenone, epoxies and alkoxysilanes.

The molar ratio of functionalizing agent to catalyst may be greater than 10 and preferably ranges from 20 to 40.

According to an advantageous embodiment of the invention, step c) of the process is further carried out in the presence of a Lewis base, in particular chosen from an ether or an amino compound, preferably tetrahydrofuran.

This embodiment is advantageous in that the presence of a Lewis base makes it possible to increase (and to facilitate) the degree of functionalization of the polydiene resulting from the process. In a process according to the invention, the contact between the stereo-regular chains transferred at the level of the metal transfer agent and the functionalization agent is maintained under conditions that are effective for the formation of a functionalized stereo-regular diene polymer. in at least one of its terminal ends. The optimization of these conditions is clearly within the skill of the person skilled in the art.

Stage c) is generally carried out for a period of between 1 hour and 12 hours, for example in at least 2 hours, at least 5 hours, or at least 10 hours, following the introduction of the functionalization agent. . It is advantageously carried out at a temperature of between 0 ° C. and 100 ° C., preferably between 20 ° C. and 80 ° C., more preferably between 40 ° C. and 60 ° C.

Thus, particularly advantageously, step c) according to the invention is carried out at a temperature of between 0 ° C. and 100 ° C., preferably between 20 ° C. and 80 ° C., more preferably between 40 ° C. and 60 ° C. ° C and maintained for a period of between 1 hour and 12 hours. d) Termination of the process:

A method according to the invention may optionally further comprise a termination step.

Such a step is performed after step c) of the method defined above.

This termination is conventional in polymer synthesis and can be carried out according to any method known to those skilled in the art. For example, termination can be accomplished by adding acidified methanol.

The polydiene formed can then be recovered by any method known to those skilled in the art. For example, the recovery of polydiene can be by precipitation in methanol. Polydiene according to the invention

The present invention also relates to a polydiene having a trans-1,4 linkage ratio of at least 85%, preferably at least 90%, and a terminal functionalization level greater than 70%, preferably greater than 80%, more preferably greater than 90%.

In particular, a polydiene according to the invention derives from the coordination catalyzed polymerization of at least one conjugated diene monomer. Thus, a polydiene according to the invention can be a homo- or a co-polydiene.

Preferably, the conjugated diene monomer (s) is chosen from 1,3-butadiene, 2,3-di (C ₁ -C ₅ alkyl) 1,3-butadienes and 1,3-butadienes. substituted, such as isoprene, di-, tri- or tetra-1,3-pentadienes, 1,3-hexadiene, 2,4-hexadiene, terpenes or any other conjugated diene comprising between 4 and 8 carbon atoms. carbon and their mixtures. The preferred terpenes are myrcene, ocimene, farnesene and mixtures thereof, more preferably myrcene.

This type of monomer (s) can also be co-polymerized with other monomers commonly used in the polymer field, for example styrene, methylstyrene, divinylbenzene, ethylene and alpha-olefins, so as to constitute statistical or block strings.

The polydienes according to the invention are further functionalized.

They may be mono-functionalized, that is to say only one of the two terminal ends of the polydiene is functionalized, or telechelic, that is to say that the two terminal ends of the polydiene are functionalized.

According to an advantageous embodiment of the invention, the polydiene is telechelic. In particular, at least 80%, preferably at least 90% of the polydiene chains are functionalized at their two terminal ends.

Preferably, the terminal functionalization of a polydiene according to the invention consists of a unit selected from carboxylic acid, aldehyde, carbonate, epoxy, alcohol, amine, nitrile, imine, amide, carbamate, thiocarbamate, hydroperoxide, phosphate, silanol groups. , halide and thiol.

Preferably, the terminal function is chosen from hydroxydiphenyl, epoxy and silanol functions.

Particularly advantageously, a polydiene according to the invention is a homo- or co-polymer of isoprene, myrcene, butadiene, and its substituted derivatives, ocimene or mono-functionalized farnesene or telechelic in position terminal and preferably by at least one hydroxydiphenyl function.

The present invention also relates to any polydiene obtained according to a process according to the invention and as defined above. APPLICATIONS

A polydiene according to the invention advantageously has good mechanical properties, in particular allowing use in the manufacture of high performance tires.

A polydiene according to the invention is also useful as a compatibilizing agent, in particular in admixture with inorganic fillers, for example based on silica, in particular in the tire industry.

A polydiene according to the invention also makes it possible to produce polymers of more elaborate architecture, in particular the synthesis of graft polymers, as macromonomer synthons.

A polydiene according to the invention can also be used as an adhesion promoter or to improve the coverage of a paint when it is integrated as an additive to a polymer formulation.

The following examples are presented by way of illustration and not limitation of the field of the invention.

METHODS OF MEASUREMENT

Microstructure:

The micro structure is determined from the NMR spectrum (1H 400.33 MHz,

13 C 100.66 MHz) obtained on a Bruker Avance II 400 (9.4 T) instrument equipped with a 5 mm inverse TBI probe at ambient temperature in C ₂ D ₂ Cl ₄ with calibration on the residual resonances of the solvent δ = 5.91 ppm (1H) and 74.0 ppm ( ¹³ C).

Functionalization:

The functionalization is demonstrated and quantified by 1 H NMR and 13 C on a Bruker Avance II 400 (9.4 T) apparatus equipped with a 5 mm inverse TBI probe at room temperature in C ₂ D ₂ Cl ₄ , integrating the aromatic signal. of the chain end. A DOSY NMR analysis (ledbpgp2s program) confirms the grafting of the function, which is a hydroxydiphenylmethylenyl function in the case of the following examples.

The polar nature of the functionalized polydienes is evidenced by measuring the contact angle using water as a reference, using the Digidrop Contact Angle Meter (GBX Scientific Instruments) and Windrop ++ software. The contact angle is measured (average of 5 experiments) with a drop of 10 μΐ _^ deposited on a glass substrate covered with a polymer film. Said polymer film is itself prepared by evaporation of a polymer solution according to the invention (50 mg of polymer / 1 ml) in toluene. As illustrated in FIG. 2, the comparison of the contact angle thus measured with that obtained on a surface covered with a trans-1,4-non-functionalized polyisoprene of reference demonstrates the more polar character of the stereo-regular polydiene functionalized by benzophenone according to the invention. Molar mass and dispersity:

The molar mass and the dispersity are measured by steric exclusion chromatography (SEC) in THF at 40 ° C. The apparatus used is a Waters chromatograph equipped with Styragel columns (HR2, HR3, HR5 and HR5E) and calibrated with reference to standard polystyrene. This method allows a separation of the polymer chains according to their size.

Polymer yield:

The polymer yield is determined gravimetrically.

EXAMPLES

All syntheses are made under argon.

Material:

Isoprene and myrcene from Sigma Aldrich.

n-BuLi at 2.1M in hexane from Sigma Aldrich or 2M in cyclohexane from Sigma-Aldrich or MeLi at 1.6M in diethyl ether from Sigma-Aldrich.

20% BEM in heptane from Texas Alkyls

Al (i-Bu) ₃ and AlEt ₃ from Sigma Aldrich.

Adduct magnesium / isoprene type [Mg (C ₅ Hg) .2THF _n] _m comprising 80% of [Mg (C ₅ H ₈₎ .2THF] _n, and 20% [Mg (C ₀ ₆ Hi) .2THF] _n prepared according to the procedure described in H. Yasuda, Y. Nakano, K. Natsukawa, H. Tani, Macromolecules, 1978, 11, 586.

Example 1 (Control): Synthesis of hydroxydiphenylmethylenyl-frora.s'-polyisoprene without transfer agent.

The trans-1,4 polyisoprene chains are obtained by polymerization of isoprene (231 mg, ie 3.40 mmol) in toluene with Nd (BH ₄ ) ₃ (THF) ₃ in combination with butylethyl magnesium (BEM) as catalyst as alkylating agent (at 17μιηο1 in Nd) for 2 hours at 50 ° C. The isoprene / Nd molar ratio is 200. Then, 4 equivalents / Nd of benzophenone are added to the reaction mixture to react for 12h at 50 ° C. The termination is carried out by adding acidified methanol.

The polymer is recovered by precipitation in methanol containing BHT (bis tert-Butyl Hydroxy Toluene) as stabilizer.

EXAMPLE 2 (CONTROL) Synthesis of hydroxydiphenylmethylenyl-collo-polymyrene without transfer agent.

A synthesis corresponding to the protocol of Example 1 was carried out, using myrcene as a monomer in place of isoprene. EXAMPLE 3 Synthesis of Hydroxydiphenylmethylenyl-Frora®-Polyisoprene and its Functionalization According to the Invention

The trans-1,4 polyisoprene chains are obtained by polymerization of isoprene (680 mg, ie 10 mmol) in toluene with Nd (BH ₄ ) 3 (THF) ₃ / BEM / AlEt _{3 as} catalyst system (at 10 μπιοΐ). in Nd and Mg and 90 μπιοΐ in Al) for 24h at 50 ° C. The isoprene / Nd molar ratio is 1000. Next, 2 equivalents of benzophenone / alkyl (106 mg) are added to the reaction mixture and mixed for 12h at 50 ° C. The polymer is recovered according to the same protocol as in Example 1.

EXAMPLE 4 Synthesis of Hydroxydiphenylmethylenyl-froras-Polymyrene and Functionalization According to the Invention

A synthesis corresponding to the protocol of Example 3 was carried out, using as catalyst system Nd (BH ₄ ) 3 (THF) 3 / BEM / AliBu ₃ (with a molar ratio Al / Nd equal to 19) and myrcene instead of isoprene. The mixture is allowed to polymerize for 72 hours at 50 ° C. In addition, the myrcene / Nd molar ratio is 200.

EXAMPLE 5 Synthesis of Hydroxydiphenylmethylenyl-Frora®-Polyisoprene and its Functionalization According to the Invention

Standard polymerization is carried out according to the protocol of Example 1.

When complete monomer conversion is achieved, excess BEM (10 x Nd equivalent) is added to the reaction mixture and then the mixture is stirred for 1h at 50 ° C. 2 equivalents / alkyl (60 mg) of benzophenone are added to the reaction mixture and then mixed for 12h at 50 ° C. The polymer is recovered according to the same protocol as in Example 1.

Example 6 Synthesis of hydroxydiphenylmethylenyl-froras-polymyrene and Functionalization According to the Invention

A synthesis corresponding to the protocol of Example 5 was implemented, using myrcene instead of isoprene. EXAMPLE 7 Synthesis of Hydroxydiphenylmethylenyl-Frora®-Polyisoprene and its Functionalization According to the Invention

The synthesis according to Example 5 was carried out by replacing the BEM with excess w-BuLi (20 x Nd equivalent).

Example 7-1: Synthesis of hydroxydiphenylmethylenyl-fm¾s'-polyisoprene and its functionalization according to the invention.

The synthesis according to Example 7 with Nd (BH ₄ ) ₃ (THF) ₃ (m = 40.6 mg, n = 0.1 mmol) and BEM (n = 0.1 mmol, BEM / Nd = 1) in 1 mL of toluene in the presence of isoprene (m = 0.681 mg, V = 1 mL, n = 0.01 mol, isoprene / Nd = 100) was implemented by replacing the BEM with w-BuLi (2 M in cyclohexane, V = 0.25 mL, n = 0.5 mmol) in excess (5 x Nd equivalent). 5 equivalents / Nd benzophenone (m = 91 mg, n = 0.5 mmol) in 2 mL of THF (V _T HF = Vi + V _To _sop rene iuene; [C] = 0.25 M benzophenone) were added to the reaction mixture then mixed for 12h at 50 ° C. The polymer is recovered according to the same protocol as in Example 1.

Example 7-2: Synthesis of hydroxydiphenylmethylenyl-frora.s'-polyisoprene and its functionalization according to the invention.

The synthesis according to Example 7-1 was carried out by replacing the w-BuLi with MeLi (1.6 M in Et ₂ O, V = 0.32 mL, n = 0.5 mmol) in excess ( 5 x equivalent Nd). The polymer is recovered according to the same protocol as in Example 1.

Example 7-3: Synthesis of hydroxydiphenylmethylenyl-polyisoprene and its functionalization according to the invention.

The synthesis according to Example 7 with Nd (BH ₄ ) ₃ (THF) ₃ (m = 20.3 mg, n = 0.05 mmol) and BEM (n = 0.05 mmol, BEM / Nd = 1) in 0.5 mL of toluene in the presence of isoprene (m = 0.340 mg, V = 0.5 mL, n = 5 mmol, isoprene / Nd = 100) was implemented by replacing the BEM with MeLi (1, 6 M in Et ₂ O, V = 0.16 mL, n = 0.25 mmol) in excess (5 x Nd equivalent). 5 equivalents / Nd benzophenone (m = 45.5 mg, n = 0.25 mmol) in 1 mL THF (VTHF = Vi + V _To _sop rene iuene; [C] = 0.25 M benzophenone) were added to the reaction mixture then mixed for 45 min at 50 ° C. The polymer is recovered according to the same protocol as in Example 1. Example 7-4: Synthesis of hydroxydiphenylmethylenyl-melras-polyisoprene and its functionalization according to the invention.

The synthesis according to Example 7-3 was carried out with reaction with the transfer agent (60 min) and with benzophenone (60 min) at room temperature. The polymer is recovered according to the same protocol as in Example 1.

EXAMPLE 8 Synthesis of Hydroxydiphenylmethylenyl-Frora-Polvisoprene and its Functionalization According to the Invention

The synthesis according to Example 7 was carried out with an isoprene / Nd molar ratio of 50.

Example 9 Synthesis of hydroxydiphenylmethylenyl-froras-polymyrene and its functionalization according to the invention.

The synthesis according to Example 7 was carried out by replacing the isoprene with myrcene.

EXAMPLE 10 Synthesis of difhydroxydiphenylmethylenyP-fraras-polyisoprene, in the presence of a di-functional alkylating agent and its functionalization according to the invention.

The synthesis according to Example 7 was carried out with an isoprene / Nd molar ratio of 100 and with as catalyst system Nd (BH ₄ ) 3 (THF) 3 / Mg (isoprenyl) _n (Mg / Nd ratio = 1). .

The monomer conversion rate, the trans-1,4 stereo-regularity and the conversion ratio were measured for each polydiene obtained according to Examples 1 to 10.

The results are summarized in Table 1 below. Table 1

Agent of Performance Rate of

1,4-trans monomer

Transfer examples in polymer Functionalisation

/ Ln (%)

excess (%) (%)

1

- 200 80 96.9 49

(Comparative)

2

- 200 82 96.4 65

(Comparative)

3

AlEt ₃ 1000 79 87.5 81

(Invention)

4

Al (/ - Bu) ₃ 200 95>90> 85

(Invention)

5

BEM 200 76 96.2 89

(Invention)

6

BEM 200 89 97 72

(Invention)

7

w-BuLi 200 100 95.3 92

(Invention)

7-1

w-BuLi 100> 95 96 98

(Invention)

7-2

MeLi 100> 95 96 98

(Invention)

7-3

MeLi 100 91 96 98

(Invention)

7-4

MeLi 100 90 96 92

(Invention)

8

w-BuLi 50 100 96.7 97

(Invention)

9

w-BuLi 200 76> 90 83

(Invention)

10

w-BuLi 100 100 96.4 99

(Invention) All the syntheses carried out made it possible to obtain trans-1,4 stereoregular polydienes, in particular more than 87%. The advantage of the role of transfer agent of the excess aluminum compound during the polymerization of the chains (Examples 3 and 4) allowed the functionalization of a large majority of the polydiene chains.

Thanks to the step of transfer of polymer chains to magnesium or lithium once the polymerization is complete (Examples 5 to 9), it has been possible to observe an even more efficient functionalization of the polydiene chains. This also makes it possible to highlight the living character of the polymerizations carried out.

Finally, the implementation of a di-functional alkylating agent (Example 10) allowed the synthesis of a telechelic stereo-regular polydiene having an even higher degree of functionalization.

On the other hand, the syntheses according to Examples 1 and 2, not in accordance with the invention, do not make it possible to obtain a satisfactory degree of functionalization of the polydienes obtained.

Claims

A method useful for the terminal functionalization of trans-1,4 stereo-regular polydiene chains obtained by coordination catalysis polymerization of at least one conjugated diene monomer, characterized in that said method comprises at least the steps of:

b) introducing, in contact with said stereo-regular channels, an excessive amount of at least one metal transfer agent and maintain this contact under conditions conducive to their transfer to said metal transfer agent, and c) contact the stereo-regular chains, transferred at said transfer agent, with at least one functionalizing agent and maintain this contact under conditions effective to the formation of a trans-1,4 stereoregular diene polymer functionalized in at least one of its extremities.

2. Method according to claim 1, characterized in that steps a) to c) are carried out continuously.

3. Method according to claim 1 or 2, characterized in that said functionalized stereo-regular diene polymer obtained at the end of step c) has a degree of terminal functionalization greater than 70%, preferably greater than 80%, more preferably greater than 90%, or even greater than 95%.

4. Method according to any one of claims 1 to 3, characterized in that the coordination catalyzed polymerization is a coordinative polymerization with chain transfer and the catalyst system comprises at least one metal catalyst and an alkylating agent, preferably in a molar ratio of alkylating agent with respect to the catalyst less than 5, preferably less than 3 and more preferably equal to 1.

5. Method according to the preceding claim, characterized in that the alkylating agent is chosen from dialkylmagnesians, alkyllithiens and trialkylaluminiums or is a di-functional alkylating agent chosen from compounds of formula (MgIsoprenyl) _n , (MgButadienyl) _n (MgMyrcenyl) _n or magnesiacyclopentane Mg (CH ₂ ) s and preferably is butylethylmagnesium.

6. Method according to any one of the preceding claims, characterized in that the metal transfer agent is chosen from dialkylmagnesians, alkyl lithium and trialkylaluminums, preferably from butylethylmagnesium, n-butyllithium, methyllithium, triisobutylaluminium and triethylaluminum.

7. Method according to any one of claims 4 to 6, characterized in that the metal transfer agent is identical to the alkylating agent and that step b) is performed consecutively to step a).

8. Method according to any one of claims 4 to 6, characterized in that the alkylating agent is introduced in excess from the beginning of the polymerization in situ and in that the alkylating agent is a dialkylmagnesian and the agent of metal transfer is a trialkylaluminum.

9. Method according to any one of the preceding claims, characterized in that the molar ratio of alkyl from the metal transfer agent relative to the catalyst is at least equal to 5 and preferably at least equal to 10 or at least less than 20.

10. Process according to any one of the preceding claims, characterized in that the functionalizing agent is chosen from carboxylic acid derivatives, ketones, aldehydes, esters, imidazolidinones, isocyanates, nitriles, epoxy, imines, amides, cyclic amines, siloxanes, phosphates, organosulfur compounds, dihalogens, carbamates, thiocarbamates, urea compounds, carbonates, lactones, oxides of carbon and dioxygen.

11. Process according to any one of the preceding claims, characterized in that the conjugated diene monomers are chosen from 1,3-butadiene and 2,3-di (C ₁ -C ₅ alkyl) 1,3-butadienes. substituted 1,3-butadienes, such as isoprene, di-, tri- or tetra-1,3-pentadienes, 1,3-hexadiene, 2,4-hexadiene, terpenes or any other conjugated diene comprising between 4 and 8 carbon atoms and mixtures thereof.

12. Method according to any one of the preceding claims, characterized in that the diene polymer chains considered in step a) have a trans-1,4 stereoregularity at a rate of more than 85%, preferably more than 90%. , preferably more than 95%.

13. Process according to any one of the preceding claims, characterized in that the catalytic system of step a) comprises a rare earth catalyst / alkylating agent pair chosen from Ln (BH ₄ ) ₃ (THF) ₃ / BEM, CpRLn. (BH ₄₎ ₂ (THF) ₂ / BEM with CpR is a cyclopentadienyl having the formula C ₅ H ₅ _ _a R _a with a an integer from 0 to 5, such as C ₅ me ₅ Ln (BH ₄₎ ₂ (THF) ₂ / BEM, LnCl ₃ (THF) ₃ / BEM and preferably comprises an Nd (BH ₄ ) ₃ (THF) ₃ catalyst and a butylethylmagnesium alkylating agent in a molar ratio to neodymium of less than 5.

14. Process according to any one of the preceding claims, characterized in that the diene polymer chains considered in stage a) are polyisoprene chains, in that the catalytic system implemented in stage a) comprises an Nd catalyst ( BH ₄ ) ₃ (THF) ₃ combined with a butylethylmagnesium alkylating agent in a molar ratio relative to neodymium equal to 1 and in that the metal chain transfer agent used in step b) is butylethylmagnesium, in a molar ratio relative to neodymium at least equal to 5 or n-butyllithium in a molar ratio relative to neodymium at least equal to 5 or methyllithium in a molar ratio relative to neodymium of at least 5.

15. Polydiene having a trans-1,4 chain ratio of at least 85%, preferably at least 90%, and a terminal functionalization level greater than 70%, preferably greater than 80%, more preferably greater than 90%.

16. Polydiene according to the preceding claim, characterized in that it derives from the coordination catalyzed polymerization of at least one conjugated diene monomer, preferably chosen from 1,3-butadiene, 2,3-di (alkyl C1-C5) 1,3-butadienes, substituted 1,3-butadienes, such as isoprene, di-, tri- or tetra-1,3-pentadienes, 1,3-hexadiene, 2,4 hexadiene, terpenes or any other conjugated diene comprising between 4 and 8 carbon atoms and mixtures thereof, in particular isoprene, butadiene, myrcene, ocimene, farnesene and their mixtures.

17. Polydiene according to claim 15 or 16, characterized in that it is a homo or co-polydiene monofunctional or telechelic, in particular telechelic.

Polydiene according to any one of Claims 15 to 17, characterized in that the terminal functionalization consists of a unit chosen from carboxylic acid, aldehyde, carbonate, epoxy, alcohol, amine, nitrile, imine, amide and carbamate groups. thiocarbamate, hydroperoxide, phosphate, silanol, halide and thiol.

19. Polydiene according to any one of claims 15 to 18, characterized in that it is a homo- or co-polymer of isoprene, myrcene, butadiene, ocimene or farnesene. mono-functionalized or telechelic terminal position and preferably by at least one hydroxydiphenyl function.

20. Polydiene according to any one of claims 15 to 19, characterized in that it is obtained according to the process according to any one of claims 1 to 14.