EP1951772A2

EP1951772A2 - Method for controlled free radical polymerization or copolymerization of methacrylic and/or methacrylate monomers or exclusively methacrylic and/or methacrylate copolymers

Info

Publication number: EP1951772A2
Application number: EP06842042A
Authority: EP
Inventors: Jean-Luc Couturier; Yohann Guillaneuf; Denis Bertin; Didier Gigmes
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2005-11-24
Filing date: 2006-11-24
Publication date: 2008-08-06
Also published as: FR2893620A1; WO2007060374A3; WO2007060374A2; US20080274074A1

Abstract

The invention concerns a method for polymerizing one or more methacrylate and/or methacrylic monomers, for the synthesis of methacrylate or methacrylic polymers or exclusively methacrylic and/or methacrylate copolymers, including a step of contacting the said one or more monomers with one at least of the compounds of formulae (I) and (II), wherein: R1 and R2 may represent a phenyl group, R3 and R4 may together form a =N-phenyl group, Z represents a group of formula CR8R9R10, wherein R8, R9 may represent methyl groups, R10 may represent a -COO-phenyl group.

Description

METHOD FOR CONTROLLED RADICAL POLYMERIZATION OR COPOLYMERIZATION OF METHACRYLIC MONOMERS AND / OR

METHACRYLATES FOR MAKING POLYMERS

METHACRYLICIDES OR METHACRYLATES OR COPOLYMERS

EXCLUSIVELY METHACRYLIC AND / OR METHACRYLATE

DESCRIPTION

TECHNICAL AREA

The present invention relates to a controlled radical polymerization or copolymerization process of methacrylic and / or methacrylate monomers and in particular methyl methacrylate, for producing methacrylate or methacrylic polymers or exclusively methacrylic and / or methacrylate copolymers.

The general field of the invention is that of controlled radical polymerization.

The controlled radical polymerization makes it possible to reduce the deactivation reactions of the growing radical species, in particular the termination stage, reactions which, in conventional radical polymerization, interrupt the growth of the polymer chain irreversibly and without control. In order to reduce the probability of termination reactions, it has been proposed to transiently and reversibly block the growing radical species, forming so-called "dormant" active species in the form of a low dissociation energy bond. This thus makes it possible to restart the polymerization and thus to obtain better conversion rates, a controlled average molecular mass (or mass) and a lower polymolecularity index than conventional radical polymerization. This also makes it possible to synthesize block copolymers by starting the synthesis of a block on the dormant species.

Recently, attempts have been made to carry out the synthesis of methacrylate polymers by controlled radical route. Thus, Rizzardo et al. in ACS Symposium

Series 1998, 685, 332 tested various nitroxides such as 2,2,6,6-tetramethyl-1-piperidinyloxy (known by the abbreviation TEMPO) of the following formula:

as a control agent in the context of the polymerization of methyl methacrylate.

The authors observed that, whatever the nitroxide used in the course of their work, the polymerization is blocked at a conversion rate of 30-40% and does not have a living character. Without being bound by the theory, they attributed this to a secondary disproportionation reaction occurring between the nitroxide and the growing macroradical to give a hydroxylamine and polymethylmethacrylate terminated by a carbon-carbon double bond.

There is therefore a real need for a method of controlled radical polymerization of methacrylic monomers and / or methacrylates allowing:

access to conversion rates higher than those encountered in the prior art;

to give the growing macroradicals a living character, thus allowing a resumption of the polymerization and possibly the synthesis of block copolymers;

to obtain polymers or copolymers of high average molecular weight (up to more than 80000 g / mol) and of low polymolecularity index.

The Applicant has discovered, surprisingly, that by using particular control agents, it was possible to implement a polymerization process having the characteristics mentioned above.

STATEMENT OF I / INVENTION

Thus, the invention relates, according to a first object, to a process for the polymerization of one or more methacrylate and / or methacrylic monomers, for the synthesis of methacrylate or methacrylic polymers or of exclusively methacrylic and / or methacrylate copolymers, comprising a step of contacting said monomer (s) with at least one of the following compounds of formula (I) and (II):

(I) (H) in which:

-A represents a hydrocarbon group forming an aromatic ring with the two carbon atoms to which it is attached, this ring may carry substituents or may carry one or more fused rings, aromatic or aliphatic, optionally substituted;

R ₁ , R ₂ , R 3 and R ₄ , which may be identical or different, each independently represent an alkyl group, an alkenyl group, an aryl group, an -OH group or an -OR ₅ group with R ₅ representing an alkyl group, alkenyl, aryl or aralkyl, -COOH, -COOR ₅ with R ₅ representing an alkyl group, an alkenyl group, an aryl group or an aralkyl group; or a -CN group; R ₃ and R ₄ may also be a hydrogen atom or R ₃ and R ₄ may be confused in = X, X represents 0 or NR ₇ , R ₇ represents an alkyl, alkenyl, aryl or aralkyl group; alkyl, alkenyl, aryl or aralkyl groups within the meaning of R 1 to R _{7 which} may comprise one or more substituents; Z represents a group of formula -CR ₈ RgRiO, in which R ₈ , R ₉ represent alkyl groups, Rio represents an alkenyl, aryl, aralkyl, CN or COORn, where Rn is H, Li, Na, K, NH ₄ ⁺ , alkyl, alkenyl, aryl, aralkyl; alkyl, alkenyl, aryl, aralkyl groups falling within the definition of Rs to Rn may comprise one or more substituents.

Before going into more detail in the description, we propose the following definitions.

By methacrylic polymer or methacrylate is meant a polymer consisting of the sequence of monomeric units derived from a methacrylic monomer or a methacrylate monomer.

By exclusively methacrylic and / or methacrylate copolymer is meant a copolymer constituted by the sequence of monomeric units derived solely from several methacrylic monomers and / or methacrylates.

Alkyl group generally means a linear or branched alkyl group comprising from 1 to 20 carbon atoms, or cyclic comprising from 3 to 20 carbon atoms. These groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, n-dodecanyl, i-butyl, t-butyl, cyclopropyl, cyclohexyl.

By aryl group is generally meant an aromatic group comprising from 6 to 20 carbon atoms. Among these groups, mention may be made of phenyl, naphthyl, tolyl and biphenyl.

By aralkyl group is generally meant an aryl group of the same definition as that given above, said group being substituted by at least one an alkyl group as defined above, such as a 2-phenyl-ethyl, t-butylbenzyl or benzyl group.

By alkenyl group is generally meant a linear or branched alkenyl group comprising from 2 to 20 carbon atoms, or cyclic comprising from 3 to 20 carbon atoms.

Examples of alkenyl groups are vinyl, allyl, cyclohexenyl.

It is specified that, when the different alkyl, alkenyl, aryl or aralkyl groups contain one or more substituents, these substituents can be chosen, for example, from halogen atoms, alcohol, ether, amine, carboxylic acid, ester, nitrile, amide, nitro, thiol, thioester, silyl, phosphine or phosphoryl.

According to the invention, A represents a hydrocarbon group forming an aromatic ring with the two carbon atoms to which it is attached, this ring may carry substituents or may carry one or more fused rings, aromatic or aliphatic, optionally substituted. In other words, the group A may represent an aryl group as defined above, namely an aromatic group which may comprise from 6 to 20 carbon atoms. It may comprise a single ring (such as a phenyl group), optionally substituted with substituents chosen, for example, from halogen atoms, alcohol, ether, amine, carboxylic acid, ester, nitrile, amide or nitro groups. , thiol, thioester, silyl, phosphine or phosphoryl. It may also include several cycles, at least one of which is a group aromatic, each of the rings may themselves be substituted by substituents chosen from halogen atoms, alcohol, ether, amine, carboxylic acid, ester, nitrile, amide, nitro, thiol, thioester, silyl, phosphine or phosphoryl groups; .

Among the compounds of formula (I), there may be mentioned, advantageously, the compounds for which A represents a phenyl group, said compounds corresponding to the following formula (Ia):

^(Ia) wherein R 1, R ₂ , R ₃ and R ₄ are as defined above.

Among the compounds of formula (Ia), there may be mentioned the compound, in which R 1 and R ₂ represents an aryl group, R ₃ and R ₄ together form a group of formula = N-Ar, the compound thus satisfying the formula

(I _to i)

Wherein Ar is an aryl group as defined above, for example a phenyl group. Among the compounds of formula (II), there may be mentioned, advantageously, the compounds, for which A represents a phenyl group and Z represents a -CR ₈ RgRiO group, said compounds thus satisfying the following formula (IIa):

(IIa) wherein R 1, R ₂ , R ₃ , R 4, R ₈ , R ₆ , R ₁₀ are as defined above.

As an example of compounds of formula (IIa), mention may be made of the particular compound of formula (II _a i) below:

(Hal)

in which the Ar, identical or different, represent an aryl group as defined above. More precisely, Ar may be a phenyl group, optionally substituted with a group -NO ₂ .

Specific compounds as defined above are as follows:

in which Ph represents a phenyl group.

The compound (s) of formula (I) and / or the compound (s) of formula (II) may be present in a content ranging from 0.005% to 10% by weight relative to the total weight of or monomers.

According to one embodiment of the invention, the method, especially when using compounds of formula (I), may also be used in the presence of a free radical initiator chosen from hydroperoxides, dialkyl peroxides and the like. , diacyl peroxides, peroxyesters, peroxydicarbonates, peroxyacetals or azo compounds.

As examples of hydroperoxides, mention may be made of tert-butyl hydroperoxide, tert-amyl hydroperoxide, cumyl hydroxide, 2,5-dimethyl-2,5-di (hydroperoxy) hexane and the like. , the diisopropylbenzene monohydroperoxide and paramenthane hydroperoxide.

As examples of dialkyl peroxides, mention may be made of 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne- (3), di-tert-butyl peroxide, di-tert-butyl peroxide and di-tert-butyl peroxide. tert-amyl, 1,3-di (tert-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne, 1,1,4,4,7,7-hexamethylcyclo -4,7-diperoxynonane, 3,3,6,6,9,9-hexamethylcyclo-1,2,4,5-tetraoxanonane.

As examples of diacyl peroxide, there may be mentioned benzoyl peroxide, lauroyl peroxide, decanoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, acetyl peroxide and cyclohexylsulphonyl peroxide.

As examples of peroxyesters, there may be mentioned tert-butyl peroxybenzoate, tert-butyl peroxyacetate, tert-butyl peroxy-3,5,5-trimethylhexanoate and peroxy-3,5,5-trimethylhexanoate. tert-amyl, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 00-tert-butyl-O-isopropyl-monoperoxycarbonate, 00-tert-butyl-O- (2-ethylhexyl) - monoperoxycarbonate, 00-tert-amyl-O- (2-ethylhexyl) -monoperoxycarbonate, tert-butyl peroxyisobutyrate, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, 2 , 5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, tert-butyl peroxyneodecanoate, tert-butyl peroxyisononanoate, tert-butyl peroxypyvalate, tert-amyl peroxypyvalate, α-peroxneodecanoate -cumyl, the peroxydecanoate of tert-amyl, tert-butyl 3-hydroxy-1,1-dimethylbutylperoxynecodecanoate and tert-butylperoxymaleate.

As examples of peroxydicarbonates, there may be mentioned di (2-ethylhexyl) peroxydicarbonate, dicyclohexyl peroxydicarbonate, di (n-propyl) peroxydicarbonate, di (4-tert-butylcyclohexyl) peroxydicarbonate.

By way of examples of peroxyacetals, mention may be made of 1,1-di (tert-butylperoxy) cyclohexane, 1,1-di (tert-butylperoxy) 3,3,5-trimethylcyclohexane, 3,3-di ( tert-butylperoxy) ethyl butyrate, ethyl 3,3-di (tert-amylperoxy) butyrate, 4,4-di (tert-butylperoxy) n-butyl valerate, 2,2-di (tert butylperoxy) butane, 1,1-di (tert-amylperoxy) cyclohexane, 2,2-bis [4,4-di (tert-butylperoxy) cyclohexyl] propane.

Preferably, the free radical initiator is selected from the group consisting of peroxyesters (such as tert-butyl peroxyneodecanoate, tert-amyl peroxyneodecanoate, tert-butyl peroxypyvalate, α-cumyl peroxyneodecanoate), peroxydicarbonates (such as di (2-ethylhexyl) peroxydicarbonate, di (n-propyl) peroxydicarbonate, dicyclohexyl peroxydicarbonate, di (4-tert-butylcyclohexyl) peroxydicarbonate) The molar ratio of the compound (s) of formula (I) and / or (II) to the free radical initiator can range from 0.05 to 1.2. According to the invention, the process relates to the preparation of methacrylate or methacrylic polymers or copolymers comprising exclusively methacrylate and / or methacrylic units.

The monomer or monomers capable of forming the polymers or copolymers prepared according to the process of the invention may be chosen from: methacrylic acid and its salts;

-the methacrylates alkyl-Ci _8, such as methyl methacrylate, lauryl methacrylate; -the cycloalkyl methacrylates, C ₅ -C _8, such as cyclohexyl methacrylate; alkenyl methacrylates, such as allyl methacrylate;

aryl methacrylates, such as phenyl methacrylate; hydroxyalkyl methacrylates, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate;

ether alkyl methacrylates, such as 2-ethoxyethyl methacrylate; alkoxy- or aryloxypolyalkyleneglycol methacrylates, such as methoxypolyethyleneglycol methacrylates, ethoxypolyethyleneglycol methacrylates, methoxypolypropyleneglycol methacrylates, methoxy-polyethyleneglycol-polypropyleneglycol methacrylates; aminoalkyl methacrylates, such as 2- (dimethylamino) ethyl methacrylate; methacrylates of amine salts, such as chloride or sulphate of

(methacryloyloxy) ethyl] trimethylammonium, [2- (methacryloyloxy) ethyl] dimethylbenzylammonium chloride or sulfate;

fluorinated methacrylates, such as methacrylate

2,2,2-trifluoroethyl;

silylated methacrylates, such as 3-methacryloylpropyltrimethylsilane; phosphorus methacrylates, such as ethylene glycol phosphate methacrylates;

hydroxyethylimidazolidone methacrylate, hydroxyethylimidazolidinone methacrylate, 2- (2-oxo-1-imidazolinyl) ethyl methacrylate; and -the mixtures thereof.

The process of the invention is particularly applicable to the preparation of polymethyl methacrylate.

The process of the invention can be applied to bulk polymerization, organic solvent, emulsion or suspension modes.

The organic solvent, when it is necessary for carrying out a polymerization mode, may be chosen from toluene, xylene, chloroform, ethyl acetate, methyl ethyl ketone, dioxane, tetrahydrofuran or dimethylformamide.

The process of the invention is generally carried out at a pressure ranging from 0.5 to 20 bar and at a temperature ranging from 50 to 180 ^° C., and preferably from 90 to 110 ^° C. The process of the invention may also comprise a step of isolating the polymer or copolymer, for example by precipitation followed by filtration. The isolated polymer or copolymer can be used directly for a given application, or it can be reintroduced subsequently into a polymerization medium for the purpose of resuming polymerization.

(alternative made possible by the living character of the polymer or copolymer obtained). In summary, the use of compounds of formula (I) and (II) have many advantages: they allow to obtain a living polymer or copolymer, which can be reengaged in polymerization or in such a way as to increase the molar mass of said polymer or copolymer, or in order to synthesize a block copolymer by introduction of another methacrylic and / or methacrylate monomer under the same polymerization conditions as those of the living polymer or copolymer synthesized first; they make it possible to obtain polymer or copolymer with good control of the polymolecularity index.

From a structural point of view, the method of the invention makes it possible to obtain polymers or copolymers having at least one reactive end having the following formula:

this end being derived from the coupling of the compounds of formula (I), introduced in free form or from homolysis of the compounds of formula (II), with a radical end of the polymer or copolymer synthesized, the other end corresponding to the formula - Z, when the control agent used is the compound of formula (II).

This polymer or copolymer having such reactive ends can be reengaged in a polymerization reaction, by means of heating (which makes it possible to render the living character of the polymer or copolymer by homolytic cleavage of the reactive ends) and a possible addition of monomers if it is not possible. 'remains more in the middle.

This polymer or copolymer having such reactive ends may also be made to undergo chemical transformation of these ends by reaction thereof with appropriate reagents.

By way of example, when the compound used corresponds to the following formula:

( ^IIa i) the polymer or copolymer resulting from the process of the invention may correspond to the following formula:

wherein P represents the main chain of the polymer or copolymer constituted by the sequence of methacrylic monomer units and / or methacrylates.

After hydrolysis of the -O-Ar bond, the -COOH group thus released can be subjected, for example, to esterification or amidification reactions. Such reactions can be exploited, for example, to condense polymers which are not obtained by radical polymerization such as polyesters, polyamides, polyethyleneimines or polyepoxides. These reactions thus make it possible to access multiple copolymer structures.

The polymers or copolymers synthesized by the process of the invention, thanks to the nature of their reactive ends, are therefore new. Thus, according to a second object, the invention relates to a methacrylic or methacrylate polymer or an exclusively methacrylic and / or methacrylate copolymer obtainable by a process as defined above. In particular, the invention relates to a polymer or copolymer comprising at least one end of formula:

with R 1 and R _{2 being} able to represent a phenyl group, and R ₃ and R _{4 being} able to form together a group = N-Ph, and possibly an end capable of satisfying the formula:

Ar can represent a phenyl group or a group

4-nitrophenyl.

It is specified that the cut lines indicate the place where the ends are fixed to the polymer or copolymer.

These polymers or copolymers find their application in all fields of application of methacrylic polymers and / or methacrylates, namely the materials used in construction, furniture, electronics, the materials that can be used as polyelectrolytes, the polymeric additives that can be used for their properties of modification of mechanical properties (impact additives) or rheology modification (dispersants, thickeners). In particular, these polymers or copolymers are used for their mechanical properties and / or their transparency properties.

These polymers and copolymers defined above can enter into the constitution of numerous compositions such as:

cosmetic compositions comprising, besides said polymers or copolymers, a physiologically acceptable medium; adhesive compositions, said compositions possibly comprising, in addition, additives such as tackifying resins, plasticizers, such as oils, in which case it will constitute a hot-melt pressure-sensitive adhesive composition (known by the abbreviation HMPSA);

thermoplastic compositions, which may furthermore comprise one or more thermoplastic polymers, such as polymethyl methacrylate, polystyrene and polyvinyl chloride. Of the compounds used in the process of the invention, some are new.

Thus, the invention relates, according to a third object, to compounds of formula (II) below:

fll) wherein A, R 1, R ₂ , R 3 and R ₄ , Z are as defined above.

Among the new compounds of formula

(II), there may be mentioned, advantageously, the compounds, for which A represents a phenyl group and Z represents a -CR ₈ RgRiO group, said compounds thus satisfying the following formula (IIa):

(IIa) wherein R 1, R ₂ , R 3, R ₄ , R ₅ , R ₉ , R ₁₀ are as defined above.

(Hal) in which the Ar, identical or different, represent an aryl group as defined above. More precisely, Ar may be a phenyl group, optionally substituted with a group -NO ₂ .

Specific compounds as defined above are as follows:

in which Ph represents a phenyl group. The compounds of formula (II) can be synthesized by a process involving the coupling between a carbon radical and a nitroxide radical.

Thus, the invention relates, according to a fourth object, to a process for the preparation of compounds of formula (II) comprising a step of reacting a nitroxide compound of formula (I) below:

(I) wherein A, R 1, R ₂ , R 3 and R ₄ are as defined above; with a compound of formula (III) below:

Z-X

(III) wherein Z is as defined above and X represents a halogen atom, such as chlorine, fluorine, bromine, iodine; in a medium comprising at least one organic solvent and an organometallic system comprising a metal salt of formula:

MA in which:

M represents a transition metal, such as Cu,

Ag or Au and preferably Cu; - A represents a halogen atom; and an organic ligand comprising at least one amino group.

For example, the organic ligand comprising at least one amino group may be chosen from: tris [2- (dimethylamino) ethyl] amine of the following formula:

N, N, N ', N', N '' -pentamethyldiethylenetriamine (known by the abbreviation PMDETA) of the following formula:

CH ₃ (CH ₃ ) ₂ N (CH ₂ ) ₂ N (CH ₂ ) ₂ N (CH ₂ ) ₂ N, N, N ', N'-tetramethylethylenediamine of the following formula:

1, 1, 1, 4, 7, 10, 10-hexamethyltriethylenetetramine (known by the abbreviation HMTETA) of the following formula:

cyclic polyamines such as:

1,4,7-trimethyl-1,4,7-triazacyclononane;

1,5,9-trimethyl-1,5,9-triazacyclododecane;

1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane.

From a practical point of view, to obtain the compounds of formula (II), a metal salt MA (M and A being as defined above) is generally mixed with stirring in an organic solvent, the organic ligand comprising at least one amino group, the compound of formula (III) and the nitroxide of formula (I) in a molar ratio of compound (III) / nitroxide (I) ranging from 1 to 1.4 and keeping the reaction medium under agitation at a temperature of between 20 ^° C. and 40 ^° C. until complete disappearance of the nitroxide (I) and then recovering the organic phase which is washed with water and then isolating the compound of formula (II) by evaporation of the organic solvent under reduced pressure.

As organic solvents, it is preferable to use aromatic hydrocarbons, such as benzene, toluene, xylenes, alkyl chlorides, and in particular dichloromethane, and / or ethers.

The metal salt used is preferably CuBr. It is also possible to introduce CuBr (in which the copper is at the oxidation state 1) and copper into the reaction medium.

The invention will now be described with respect to the following examples given for illustrative and not limiting.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

EXAMPLE 1

This example illustrates the preparation of an alkoxyamine of the following formula:

In a nitrogen purged reactor, the charge is

10 mL of toluene, 579 mg of N, N, N ', N', N '' - pentamethyldiethylenetriamine (3.6 mmol), 240 mg of

CuBr (1.8 mmol) and 106 mg of copper powder

(1.8 mmol). 406 mg of phenyl ester of 2-bromo-2-methylpropionic acid (1.8 mmol) and

418 mg of nitroxide DPAIO (1.2 mmol) dissolved in 10 ml of toluene, said nitroxide DPAIO corresponding to the following formula:

Nitroxide DPA10 is prepared according to Tetraedron, 1975, 31, 1745.

Allowed to react for 24 hours at room temperature. The reaction mixture is filtered through Celite and then washed with water (4 * 20 mL) to remove the copper complexes. The organic phase is dried over magnesium sulfate and then evaporated under vacuum. The product is purified by chromatography on a silica column (eluent pentane / diethyl ether: 9/1). 460 mg of the compound is obtained in the form of a yellow powder (yield = 75%).

The analytical characteristics of the compound are as follows: ¹ H NMR (CDCl ₃ , 300.13 MHz): 1.30 ppm (s, 6H); 6.31 (d, J (H, H) = 7.74 Hz, 1H); 6.56 (t, J (H, H) = 7.56 Hz, 1H); 6.68 (d, J (H, H) = 7.93 Hz, 2H); 6.81 (d, J (H, H) = 8.12 Hz, 2H); 6.99 (t, J (H, H) = 7.37 Hz, 1H); 7.12 (m, 1H); 7.18 to 7.31 (m, 12H); 7.55 (m, 4H). Elemental analysis obtained (%): C = 80.55; H, 5.81; N = 5.06 (calculated C = 80.27, H = 5.61, N = 5.20). EXAMPLE 2

In a nitrogen purged reactor, 40 ml of toluene, 1.34 g of N, N, N ', N', N '' - pentamethyldiethylenetriamine (15.42 mmol), 1.11 g of CuBr ( 7.71 mmol) and 0.49 g of copper powder (7.71 mmol). 2.22 g of 4-nitrophenyl ester of 2-bromo-2-methylpropionic acid (7.71 mmol) and 1.93 mg of nitroxide DPAIO (1.2 mmol) dissolved in 40 ml of toluene are added, said nitroxide DPAIO corresponding to the following formula:

Allowed to react for 24 hours at room temperature. The reaction mixture is filtered through Celite and then washed with water (4 * 20 mL) to remove the copper complexes. The organic phase is dried over magnesium sulfate and then evaporated under vacuum. The product is purified by chromatography on a silica column

(pentane / diethyl ether eluent: 4/1). 1.8 g of compound are obtained in the form of a yellow powder (yield = 60%). The analytical characteristics of the compound are as follows:

¹ H NMR (CDCl ₃ , 300.13 MHz): 1.46 ppm (s, 6H); 6.41 (d, J (H, H) = 7.83 Hz, 1H); 6.67 (t, J (H, H) = 6.57 Hz, 1H); 6.75 (d, J (H, H) = 7.45 Hz, 2H); 6.98 (d, J (H, H) = 9.1 Hz, 2H); 7.08 (t, J (H, H) = 7.33 Hz, 1H); 7.29-7.82 (m, 10H); 7.61 (m, 4H); 8.18 (d, J (H, H) = 9.1 Hz, 2H). Elemental analysis obtained (%): C = 73, 64; H, 5.13; N = 7.12 (calculated C = 74.09, H = 5.01, N = 7.20).

EXAMPLE 3

This example illustrates the preparation of a polymethyl methacrylate in a medium comprising:

a DPAIO compound; a free radical initiator: di (4-tert-butylcyclohexyl) peroxydicarbonate.

In a Parr reactor of 100 ml, 40 g of methyl methacrylate (0.4 mol), 0.376 g of DPAIO (1 mmol) of formula:

and 0.543 g of di (4-tert-butylcyclohexyl) peroxydicarbonate (Perkadox 16 in Akzo-1.35 mmol) The mixture is degassed by bubbling nitrogen for 30 minutes, then the reactor is closed and the temperature is increased to 100 ⁰ C. the conversion rates were measured by proton NMR (by comparing the integrations of the peaks of vinyl groups and methyl). the molar masses in number and weight are measured by gel permeation using a universal calibration and Mark-Houwink parameters (K = 0, 001298, α = 0.688).

The results are given in the following table.

EXAMPLE 4

In this example, the procedure is the same as in Example 3, except that 0.38 g of di (4-tert-butylcyclohexyl) peroxydicarbonate (0.95 mmol) is used.

The results are given in the following table.

EXAMPLE 5

This example illustrates a polymerization recovery test with methyl methacrylate.

The polymer synthesized in Example 3 is isolated by double precipitation (dissolution in THF, precipitation with ethanol) (Mn obtained = 30500 g / mol).

7.5 g of the polymer thus obtained (0.25 mmol) is introduced into the Parr reactor in the presence of 60 g of methyl methacrylate (0.6 mol-target mass: 274500 g / mol) and the mixture is heated to a temperature of 100 ^° C.

The results are given in the following table.

This example illustrates that the polymer obtained in Example 3 partially has a living character and can be re-engaged in a polymerization without adding additional initiator.

It is thus possible to synthesize block copolymers by the process of the invention. EXAMPLE 6

In a 100 ml Parr reactor, 40 g of methyl methacrylate (0.4 mol) and 0.54 g of compound prepared in Example 1 (1 mmol-target mass = 40000 g / mol) are introduced. The mixture is degassed by bubbling nitrogen for 30 minutes, then the temperature is increased to 100 ^° C.

The results are given in the following table.

This example illustrates that, in the case of the process of the invention, the evolution of the molecular masses is linear with the conversion rate, the masses obtained are close to the theoretical masses and the polydispersity indices are low. This reflects the controlled and living nature of the process of the invention.

EXAMPLE 7

In this example, one operates under the same conditions as in example 6, except that one used 0.27 g of compound prepared according to Example 1 (0.5 mmol-mass target: 80000 g / mol.

The results are given in the following table.

EXAMPLE 8

In this example, the procedure is the same as in Example 6, except that 0.58 g of the alkoxyamine prepared according to Example 2 (1 mmol-target mass: 40000 g) are used. / mol.

The results are given in the following example.

EXAMPLE 9

In this example, one operates under the same conditions as in Example 6, except that one uses 0.29 g of the alkoxyamine prepared according to Example 2 (0.5 mmol-target mass: 80000 g / mol.

The results are given in the following example.

Claims

A process for the polymerization of one or more methacrylate and / or methacrylic monomers, for the synthesis of methacrylate or methacrylic polymers or of exclusively methacrylic and / or methacrylate copolymers, comprising a step of contacting said monomer (s) with one at least one of the following compounds of formula (I) and (II):

(I) (H) in which:

R ₁ , R ₂ , R 3 and R ₄ , which may be identical or different, each independently represent an alkyl group, an alkenyl group, an aryl group, an -OH group or an -OR ₅ group with R ₅ representing an alkyl group, alkenyl, aryl or aralkyl, a -COOH group, a -COOR ₅ group with R ₅ representing an alkyl group, a group alkenyl, an aryl group or an aralkyl group; or a -CN group; R ₃ and R ₄ may also represent a hydrogen atom or R ₃ and R ₄ may be confused in = X, X representing 0 or NR ₇ , R ₇ representing an alkyl, alkenyl, aryl or aralkyl group; alkyl, alkenyl, aryl or aralkyl groups within the meaning of R 1 to R _{7 which} may comprise one or more substituents; Z represents a group of formula -CR ₈ RgRiO, in which R ₈ , R ₉ represent alkyl groups, Rio represents an alkenyl, aryl, aralkyl, CN or COORn group, with Rn representing H, Li, Na, K, NH _4; ⁺ , an alkyl, alkenyl, aryl, aralkyl group; the alkyl, alkenyl, aryl and aralkyl groups falling within the definition of R ₈ to Rn may comprise one or more substituents.

2. Process according to claim 1, wherein the compounds represented by the following formula (Ia) are chosen as compounds of formula (I):

(Ia) wherein R 1, R ₂ , R ₃ and R ₄ are as defined in claim 1.

3. The process as claimed in claim 2, in which R 1 and R ₂ represent an aryl group, R ₃ and R _4. together form a group of formula = N-Ar, Ar corresponding to an aryl group.

4. Process according to claim 1, wherein the compounds represented by the following formula (IIa) are chosen as compounds of formula (II):

(IIa) wherein R 1, R ₂ , R ₃ , R 4, R ₅ , R 9, R 10 are as defined in claim 1.

5. Process according to claim 4, in which R 1 and R ₂ represent an aryl group, R ₃ and R ₄ together form a group of formula = N-Ar, Ar representing an aryl group, R ₈ and R ₉ represent methyl groups. , Rio represents a group of formula -COOAr, Ar representing an aryl group.

6. Method according to claim 4 or 5, wherein one chooses as compounds of formula (IIa) one of the compounds of formula following:

in which Ph represents a phenyl group

7. Process according to any one of the preceding claims, in which the step of bringing into contact is carried out, in addition, in the presence of a free radical initiator chosen from hydroperoxides, dialkyl peroxides and diacyl peroxides. peroxyesters, peroxydicarbonates, peroxyacetals or azo compounds.

8. The method of claim 7, wherein the free radical initiator is selected from peroxyesters, peroxydicarbonates.

9. The method of claim 7 or 8, wherein the peroxyesters are selected from tert-butyl peroxyneodecanoate, tert-amyl peroxyneodecanoate, tert-butyl peroxypyvalate, α-cumyl peroxneodecanoate.

The process according to claim 7 or 8, wherein the peroxydicarbonates are selected from di (2-ethylhexyl) peroxydicarbonate, di (n-propyl) peroxydicarbonate, dicyclohexyl peroxydicarbonate, di (4-tert-butylcyclohexyl) peroxydicarbonate.

11. A method according to any preceding claim, wherein the or methacrylic monomers and / or methacrylates are selected from methacrylic acid and its salts, methacrylates, alkyl-Ci ₈ cycloalkyl methacrylates C ₅ -C ₈ alkenyl methacrylates, aryl methacrylates, methacrylates, hydroxyalkyl methacrylates, etheralkyl, methacrylates, alkoxy- or aryloxy-polyalkylene glycol methacrylates, aminoalkyl methacrylates amine salts, fluorinated methacrylates, silylated methacrylates, phosphorus methacrylates, hydroxyethylimidazolidone methacrylate, hydroxyethylimidazolidinone methacrylate, 2- (2-oxo-1-imidazolinyl) ethyl methacrylate; and mixtures thereof.

The process according to any one of the preceding claims, wherein the polymer prepared is polymethyl methacrylate.

13. Methacrylate or methacrylic polymer or exclusively methacrylic and / or methacrylate copolymer obtainable by a process as defined according to any one of claims 1 to 12.

14. Cosmetic composition comprising in a physiologically acceptable medium at least one polymer or copolymer as defined in claim 13.

15. Adhesive composition comprising at least one polymer or copolymer as defined in claim 13.

16. Thermoplastic composition comprising at least one polymer or copolymer as defined in claim 13.

17. A compound of the following formula (II):

fli) in which:

-A represents a hydrocarbon group forming an aromatic ring with the two carbon atoms to which it is attached, this ring may carry substituents or may carry one or more fused rings, aromatic or aliphatic, optionally substituted; -Ri, R-2, R-3 and R ₄ , which may be identical or different, each independently represent an alkyl group, an alkenyl group, an aryl group, an -OH group, a group -OR ₅ with R ₅ representing an alkyl, alkenyl, aryl or aralkyl group, a -COOH group, a -COOR ₆ group with R ₆ representing an alkyl group, an alkenyl group, an aryl group or an aralkyl group; or a -CN group; R ₃ and R ₄ may also represent a hydrogen atom or R ₃ and R ₄ may be confused in = X, X representing 0 or NR ₇ , R ₇ representing an alkyl, alkenyl, aryl or aralkyl group; alkyl, alkenyl, aryl or aralkyl groups within the meaning of R 1 to R _{7 which} may comprise one or more substituents;

Z represents a group of formula -CR ₈ RgRiO, in which R ₈ , Rg represent alkyl groups, Ri ₀ represents an alkenyl, aryl, aralkyl, CN or COORn group, Rn representing H, Li, Na, K, NH _4; ⁺ , an alkyl, alkenyl, aryl, aralkyl group; the alkyl, alkenyl, aryl and aralkyl groups falling within the definition of R ₈ to Rn may comprise one or more substituents.

18. The compound of claim 17 having the following formula (IIa):

(IIa) wherein Ri, R2, R3, R _4, Rs? R-9? Rio are as defined in claim 14.

19. A compound according to claim 18, in which R 1 and R ₂ represent an aryl group, R ₃ and R ₄ together form a group of formula = N-Ar, Ar representing an aryl group, R ₈ and R ₉ represent methyl groups. , Rio represents a group of formula - COOAr, Ar representing an aryl group.

20. A compound according to any one of claims 17 to 19, corresponding to one of the following formulas:

in which Ph represents a phenyl group,

21. Process for preparing a compound of formula (II) below: fli) in which:

-A represents a hydrocarbon group forming an aromatic ring with the two carbon atoms to which it is attached, this ring may carry substituents or may carry one or more fused rings, aromatic or aliphatic, optionally substituted; R ₁ , R ₂ , R 3 and R ₄ , which may be identical or different, each independently represent an alkyl group, an alkenyl group, an aryl group, an -OH group or an -OR ₅ group with R ₅ representing an alkyl group, alkenyl, aryl or aralkyl, -COOH, -COOR ₅ with R ₅ representing an alkyl group, an alkenyl group, an aryl group or an aralkyl group; or a -CN group; R ₃ and R ₄ may also represent a hydrogen atom or R ₃ and R ₄ may be confused in = X, X representing 0 or NR ₇ , R ₇ representing an alkyl, alkenyl, aryl or aralkyl group; alkyl, alkenyl, aryl or aralkyl groups within the meaning of R 1 to R _{7 which} may comprise one or more substituents;

Z represents a group of formula -CR ₈ RgRiO, in which R ₈ , R ₉ represent alkyl groups, Rio represents an alkenyl, aryl, aralkyl, CN or COORn, wherein Rn is H, Li, Na, K, NH ₄ ⁺ , alkyl, alkenyl, aryl, aralkyl; alkyl, alkenyl, aryl, aralkyl groups falling within the definition of R ₈ to Rn may comprise one or more substituents; said process comprising a step of reacting a nitroxide compound of the following formula (I):

Z-X (III) wherein Z is as defined above and X is a halogen atom; in a medium comprising at least one organic solvent and an organometallic system comprising a metal salt of formula

MY

M represents a transition metal;

- A represents a halogen atom; and and an organic ligand comprising at least one amino group.

22. The method of claim 21, wherein M is Cu.

23. The method of claim 21 or 22, wherein the organic ligand comprising at least one amino group is selected from: tris [2- (dimethylamino) ethyl] amine of the following formula:

N, N, N ', N', N '' -pentamethyldiethylenetriamine of the following formula:

CH ₃ (CH ₃ ) ₂ N (CH ₂ ) ₂ N (CH ₂ ) ₂ N (CH ₃ ) ₂

N, N, N ', N'-tetramethylethylenediamine of the following formula:

cyclic polyamines.