Trace element and its use in producing water-soluble hybrid polymers

Abstract

The invention relates to an oligo-initiator, its synthesis process, and its use for producing water-soluble hybrid polymers. It also relates to a water-soluble hybrid polymer obtained by a synthesis process comprising the functionalization of a biopolymer by reacting its functional groups with the functional groups of the oligo-initiator, enabling the extension of synthetic polymer chains, thus forming said water-soluble hybrid polymer. The invention also aims at the use of the water-soluble hybrid polymer in various fields of application.

Description

Title of the invention: OLIGO-INITIATOR AND ITS USE FOR PRODUCING WATER-SOLUBLE HYBRID POLYMERS FIELD OF THE INVENTION

[0001] The present invention relates to an oligo-initiator and its use for producing water-soluble hybrid polymers. More specifically, the process for producing water-soluble hybrid polymers comprises the functionalization of a biopolymer by reaction of its functional groups with the functional groups of the oligo-initiator according to the invention; thus allowing the extension of synthetic polymer chains, to form water-soluble hybrid polymers. The invention also relates to the hybrid polymer thus obtained as well as its use in various fields of application. PREVIOUS ART

[0002] The synthesis of hybrid polymers, that is to say of a polymeric entity combining two polymers of different nature, has been the subject of enormous research and development efforts in recent years.

[0003] Among these hybrid polymers, we find hybrid polymers combining biopolymers from natural and / or renewable resources and synthetic polymers from fossil resources. These hybrid polymers are of significant interest in the chemical industry due to their application performances which are similar to those of synthetic polymers, their functional properties and their sustainable development potential. These characteristics make them attractive polymers for many applications, offering opportunities for innovation and development of ever more efficient and environmentally friendly products.

[0004] There are three conventional methods for synthesizing such hybrid polymers.

[0005] The first method, called "grafting through", consists of a copolymerization between a monomer and a biopolymer. This method allows branches or side chains to be added, in a heterogeneous or homogeneous manner depending on the reactivity ratio between the terminal functional group of the biopolymer and the monomers. In this case, the side chains are biopolymeric grafts. To avoid any steric hindrance, these biopolymeric side chains are often hydrolyzed to obtain low molecular weight grafts, as presented in patent FR 2934268.

[0006] In the second method, called "grafting from", a biopolymeric backbone is chemically modified in order to introduce active sites capable of initiating the growth of a polymer chain. Initiation sites can be incorporated by copolymerization in a post-polymerization reaction, or already be part of the biopolymer. The number of grafted chains can be controlled by the number of active sites.

[0007] The third method, called "grafting onto", consists of grafting preformed polymers or polymeric units onto biopolymeric substrates. This method involves a covalent chemical bond between the pre-existing polymers and the biopolymeric substrates. Different chemical reagents are required to functionalize said substrate, in addition to additional treatments that can be carried out to strengthen the stability of these covalent bonds.

[0008] These three methods require rigorous experimental conditions. In addition, when working with a biopolymer as a substrate, it is difficult, if not impossible, to avoid side reactions, including the formation of ungrafted polymers, degradation of the grafted chains or the final biopolymer, and / or crosslinking of the grafted chains. Since the majority of biopolymers are polyfunctional, the slightest modification leads to cascade reactions and subsequently to uncontrolled grafting onto the biopolymeric backbone.

[0009] None of these methods makes it possible to obtain well-defined polymers whose structure is controlled, according to mild copolymerization conditions, that is to say with a limited number of reagents and polymerization reactions but also without dangerous catalyst, in an aqueous medium and without significant energy input.

[0010] To address this problem, the Applicant has developed a new hybrid polymer obtained using a synthesis process situated between the “grafting from” method and the “grafting onto” method, and involving mild copolymerization conditions. Statement of the invention

[0011] The subject of the present invention is an oligo-initiator of formula (I) below, its process for obtaining, and its use for producing water-soluble hybrid polymers.

[0012] According to the invention, the oligo-initiator is of the following formula (I):

[0013] [Chem.l] S --S--A--Q--R2 R 1 -- Z

[0014] (I)

[0015] in which;

[0016] Z= O, S or NR3

[0017] R1, R2 and R3, identical or different, represent:

[0018] an optionally substituted alkyl, acyl, aryl, alkene or alkyne group (i), or

[0019] a carbon ring (ii), saturated or unsaturated, optionally substituted or aromatic, or

[0020] a heterocycle (iii), saturated or unsaturated, optionally substituted,

[0021] these groups and rings (i), (ii) and (iii) may be substituted by substituted phenyl groups, substituted aromatic groups or alkoxycarbonyl or aryloxycarbonyl groups (- COOR), carboxy (- COOH), acyloxy (- O2CR), carbamoyl (-CONR2), cyano (- CN), alkylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkyl-carbonyl, phthalimido, maleimido, succinimido, amidino, guanidimo, hydroxy (- OH), amino (- NR2), halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl, groups having a hydrophilic or ionic character such as alkali salts of carboxylic acids, alkali salts of sulfonic acid, polyalkylene oxide chains (POE, POP), the substituents cationic, quaternary ammonium salts,

[0022] R representing a C2-C2o alkyl or aryl group,

[0023] R3 may further represent a hydrogen atom;

[0024] A is a monomeric unit or a linear or structured polymer chain comprising identical or different hydrophilic monomers comprising at least one unsaturated ethylenic function, with nAcst an integer between 0 and 500,

[0025] Q is a monomeric unit or a linear or structured polymer chain comprising nQ monomers chosen from those having at least one reactive functional group (frQ) of the epoxide and / or anhydride and / or hydroxyl and / or isocyanate and / or acetal and / or aldehyde and / or carboxylic acid and / or ester and / or vinyl type, with nQ being an integer between 1 and 1000.

[0026] The present invention also relates to a water-soluble hybrid polymer obtained according to a specific synthesis process, using the oligo-initiator according to the invention.

[0027] The invention relates to a water-soluble hybrid polymer PH obtained according to a process comprising at least the following successive steps: 1. Functionalization of a biopolymer Bi by reaction of at least one of its reactive functional groups (frB) with at least one reactive functional group (frQ) of the oligo-initiator, to obtain a functionalized biopolymer B2, 2. Polymerization of hydrophilic monomers comprising at least one ethylenic unsaturation on at least one oligo-initiator of the functionalized biopolymer B2 to form at least one side chain L, and thus obtain the hybrid polymer PH, characterized in that the oligo-initiator is of formula (I)

[0028] [Chem.l] S --S--A--Q--R2 R 1 -- Z

[0029] (I)

[0030] in which;

[0031] Z=O, S or NR3

[0032] R1, R2 and R3, identical or different, represent:

[0033] an optionally substituted alkyl, acyl, aryl, alkene or alkyne group (i), or

[0034] a carbon ring (ii), saturated or unsaturated, optionally substituted or aromatic, or

[0035] a heterocycle (iii), saturated or unsaturated, optionally substituted,

[0036] these groups and rings (i), (ii) and (iii) may be substituted by substituted phenyl groups, substituted aromatic groups or alkoxycarbonyl or aryloxycarbonyl groups (- COOR), carboxy (- COOH), acyloxy (- O2CR), carbamoyl (-CONR2), cyano (- CN), alkylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkyl-carbonyl, phthalimido, maleimido, succinimido, amidino, guanidimo, hydroxy (- OH), amino (- NR2), halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl, groups having a hydrophilic or ionic character such as alkali salts of carboxylic acids, alkali salts of sulfonic acid, polyalkylene oxide chains (POE, POP), the substituents cationic, quaternary ammonium salts,

[0037] R representing a C2-C20j alkyl or aryl group

[0038] R3 may further represent a hydrogen atom;

[0039] A is a monomeric unit or a linear or structured polymer chain comprising nA identical or different hydrophilic monomers comprising at least one unsaturated ethylenic function, with nAcst an integer between 0 and 500,

[0040] Q is a monomeric unit or a linear or structured polymer chain comprising nQ monomers chosen from those having at least one reactive functional group (frQ) of the epoxide and / or anhydride and / or hydroxyl and / or isocyanate and / or acetal and / or aldehyde and / or carboxylic acid and / or ester and / or vinyl type, with nQ being an integer between 1 and 1000,

[0041] characterized in that the biopolymer Bi is native or modified, and comprises at least one reactive functional group (frB) of hydroxy and / or carboxy and / or anhydride and / or amine and / or amide and / or vinyl type, and / or phosphate and / or sulfonate and / or ester and / or aldehyde and / or ketone and / or silane, and / or isocyanate and / or nitrile and / or halide acyl.

[0042] The present invention also relates to the use of the water-soluble hybrid polymer PH according to the invention in: the recovery of hydrocarbons (oil or gas); the drilling of wells; the cementing of wells; the stimulation of hydrocarbon wells (oil or gas), for example hydraulic fracturing, conforming, diversion; the treatment of water in open, closed or semi-closed circuits; the treatment of fermentation musts; the treatment of sludge; construction; the manufacture of paper or cardboard; the field of batteries; the treatment of wood; the treatment of hydraulic composition (concrete, cement, mortar and aggregates); in the mining industry; the formulation of cosmetic products; the formulation of detergents; the manufacture of textiles; geothermal energy or agriculture.

[0043] Finally, the present invention also relates to the use of the water-soluble hybrid polymer PH according to the invention as a flocculant, coagulant, dispersant, binding agent, fixing agent, viscosity reducing agent, thickening agent, friction reducing agent, drainage agent, charge retention agent, dehydration agent, conditioning agent, stabilizing agent, film-forming agent, sizing agent or clay inhibitor. BRIEF DESCRIPTION OF THE FIGURES

[0044] [Fig.l]

[0045] [Fig.l] Representation of the hybrid polymer PH.

[0046] In this case, the bold black line represents a biopolymer chain, for example of the polysaccharide type; carboxymethylcellulose, to which the oligo-initiator is covalently bound. Hydrophilic monomers comprising at least one ethylenic unsaturation are polymerized on the oligo-initiator (see under the arrow) to obtain side chains L. The hybrid polymer PH thus obtained consists of a skeleton formed by the biopolymer B2 to which synthetic side polymer chains L are covalently bound. The hybrid polymer PH thus obtained is water-soluble.

[0047] [Fig.2]

[0048] [Fig.2] NMR spectrum of a PH hybrid polymer.

[0049] [Fig.2] illustrates the spectrum of the water-soluble hybrid polymer PH exemplified in the present application.

[0050] The NMR analysis was carried out on a Bruker 400 MHz ASCEND (TM) Avance III HD type device equipped with a BBFO+ type probe. DETAILED DESCRIPTION OF THE INVENTION

[0051] Throughout this application, the following definitions apply unless specifically indicated otherwise.

[0052] The term "hybrid polymer" refers to the hybrid polymer resulting from the process according to the invention. Either a polymer containing a natural and / or renewable part, and a synthetic polymer derived from fossil resources.

[0053] By "water-soluble hybrid polymer" is meant a hybrid polymer for which all the molecular weight fractions of the hybrid polymer tested have a solubility >2 g / L, demonstrated by any suitable means, when dissolved under stirring for 24 hours at 20°C at pH 7 and with a concentration of 10 g / 1000 ml in deionized water, according to the instructions of the OECD (test no. 120, test no. 105).

[0054] By “biopolymer” we mean polymers derived from living organisms or polymers synthesized from renewable resources.

[0055] By "biopolymer Bi" is meant a biopolymer before its functionalization by the oligo-initiator, according to the present invention. By "biopolymer B2" is meant a biopolymer Bi after its functionalization by the oligo-initiator, according to the present invention.

[0056] In the present application, the term "synthetic side chains" means a product formed by the polymerization of at least one synthetic hydrophilic monomer having at least one ethylenic unsaturation. The term "synthetic" does not exclude the monomers or polymers derived from patents: FR3125048, FR3125045, FR3125044, FR3125043, FR3125046, WO2023 / 281233, EP4175939, WO2023 / 281088, WO2023 / 281077, WO2023 / 281076, WO2023 / 281078, WO2023 / 281084, WO2023 / 281081.

[0057] As used herein, the term "hydrophilic monomer" means a monomer whose octanol / water partition coefficient, Kow, is less than 1, determined at a temperature of 25°C and with a pH between 6 and 8,

[0058] The partition coefficient Kow being defined as follows:

[0059] [Math.l] „ [monomer]octcmoi Æ 67 W — ? ; T" [monomer] water

[0060] With

[0061] [monomer]octanol = equilibrium concentration of monomer solubility in g / L in n-octanol

[0062] [monomer]water = concentration of the monomer at equilibrium in g / L in water.

[0063] By “X and / or Y” is meant “X”, or “Y”, or “X and Y”.

[0064] By “oligo-initiator” is meant a radical initiator capable of forming radicals.

[0065] By structured polymer chain is meant a non-linear polymer chain which has one or more side chains.

[0066] Also part of the invention are all possible combinations between the various embodiments disclosed, whether preferred or exemplary. Furthermore, when ranges of values ​​are indicated, the limits are part of these ranges. The disclosure also includes all combinations between the limits of these ranges of values. For example, the ranges of values ​​"1-20, preferably 5-15", imply the disclosure of the ranges "1-5", "1-15", "5-20" and "15-20" and the values ​​1, 5, 15 and 20.

[0067] The present invention provides a water-soluble hybrid polymer PH obtained according to a synthesis process comprising the functionalization of a biopolymer Bi by reaction of its reactive functional groups with the reactive functional groups of an oligo-initiator, allowing the extension of synthetic side chains.

[0068] The Oligo-initiator

[0069] One aspect of the present invention is to provide an oligo-initiator.

[0070] The latter allows the synthesis of water-soluble polymer, more precisely the synthesis of water-soluble hybrid polymer.

[0071] The oligo-initiator preferably has a weight-average molecular weight of between 350 and 1,500,000 Da, preferably between 500 and 500,000 Da, even more preferably between 1,500 and 100,000 Da.

[0072] According to the present invention, the oligo-initiator is of formula (I):

[0073] [Chem.l] S --s--A--Q--R2 R 1 -- Z

[0074] (I)

[0075] in which;

[0076] Z= O, S or NR3

[0077] R1, R2 and R3, identical or different, represent:

[0078] an optionally substituted alkyl, acyl, aryl, alkene or alkyne group (i), or

[0079] a carbon ring (ii), saturated or unsaturated, optionally substituted or aromatic, or

[0080] a heterocycle (iii), saturated or unsaturated, optionally substituted,

[0081] these groups and rings (i), (ii) and (iii) may be substituted by substituted phenyl groups, substituted aromatic groups or alkoxycarbonyl or aryloxycarbonyl groups (- COOR), carboxy (- COOH), acyloxy (- O2CR), carbamoyl (-CONR2), cyano (- CN), alkylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkyl-carbonyl, phthalimido, maleimido, succinimido, amidino, guanidimo, hydroxy (- OH), amino (- NR2), halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl, groups having a hydrophilic or ionic character such as alkali salts of carboxylic acids, alkali salts of sulfonic acid, polyalkylene oxide chains (POE, POP), cationic substituents, quaternary ammonium salts,

[0082] R representing a C2-C20j alkyl or aryl group

[0083] R3 may further represent a hydrogen atom;

[0084] A is a monomeric unit or a linear or structured polymer chain comprising nA identical or different hydrophilic monomers comprising at least one unsaturated ethylenic function, with nAcst an integer between 0 and 500,

[0085] Q is a monomeric unit or a linear or structured polymer chain comprising nQ monomers chosen from those having at least one reactive functional group (frQ) of the epoxide and / or anhydride and / or hydroxyl and / or isocyanate and / or acetal and / or aldehyde and / or carboxylic acid and / or ester and / or vinyl type, with nQ being an integer between 1 and 1000.

[0086] In the N(R)2 functions, the two R groups can be identical or different from each other.

[0087] The preferences set out below can be chosen independently of one another or combined with one another.

[0088] Preferably, the oligo-initiator is of formula (I) in which Z = O.

[0089] Preferably, the oligo-initiator is of formula (I) in which:

[0090] Z = O and ;

[0091] R1 and R2 represent an optionally substituted alkyl, acyl, aryl, alkene or alkyne group.

[0092] Preferably, A is a monomeric unit or a linear or structured polymer chain comprising from 1 to 300 monomeric units.

[0093] Preferably, Q is a monomeric unit or a linear or structured polymer chain comprising from 1 to 500 monomeric units.

[0094] Preferably, A is a monomeric unit or a polymer chain comprising hydrophilic monomers comprising at least one unsaturated ethylenic function chosen from non-ionic and / or anionic and / or cationic and / or zwitterionic monomers.

[0095] The non-ionic monomers are preferably chosen from the group comprising water-soluble vinyl monomers, such as acrylamide, methacrylamide, N-alkylacrylamides, N-alkylmethacrylamides, N,N-dialkyl acrylamides (for example N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N-dialkylmethacrylamides, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinyl caprolactam, N-vinylformamide (NVF), N-vinyl acetamide, N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, acrylonitrile, maleic anhydride, itaconic anhydride, itaconamide, vinylpyridine, hydroxyalkyl (meth)acrylates, thioalkyl (meth)acrylates, isoprenol and its alkoxylated derivatives, hydroxyethyl (meth)acrylates and their alkoxylated derivatives, hydroxypropylacrylate and its alkoxylated derivatives, vinyl acetate, and mixtures thereof. Among these non-ionic monomers, the alkyl groups are advantageously C1-C5, more advantageously C1-C3. These are preferably linear alkyls.

[0096] The anionic monomers are preferentially chosen from acrylic acid; methacrylic acid; dimethylacrylic acid; itaconic acid; crotonic acid; maleic acid; fumaric acid; acrylamido undecanoic acid; 3-acrylamido 3-methylbutanoic acid; maleic anhydride; strong acid monomers having for example a sulfonic acid or phosphonic acid function such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-1,3-disulfonic acid, 2-sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), 2-acrylamido-2-methylpropane disulfonic acid;water-soluble salts of these monomers such as their alkali metal salts (as distinct from the crystalline form of the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid), alkaline earth metal salts, or ammonium salts; and mixtures thereof.

[0097] In a particular embodiment, the anionic hydrophilic monomer(s) may be salified.

[0098] By salified is meant the substitution of a proton of at least one acid function of the type -R(=O)-OH (with R= P, S or C) of the anionic monomer by a metal or ammonium cation to form a salt of the type -R(=O)-OX (X being a metal or ammonium cation). In other words, the non-salified form corresponds to the acid form of the monomer, for example RC(=O)-OH in the case of the carboxylic acid function, whereas the salified form of the monomer corresponds to the form RC(=O)-O- X+, X+ corresponding to an alkali or ammonium cation. The salification of the acid functions of the polymer may be partial or total.

[0099] The salified form advantageously corresponds to the salts of alkali metals (Li, Na, K, etc.), alkaline earth metals (Ca, Mg, etc.) or ammonium (for example the ammonium ion or a tertiary ammonium). The preferred salts are the sodium salts.

[0100] Salification can be done before or after polymerization.

[0101] The cationic monomers are advantageously chosen from the monomers derived from vinyl-type units (advantageously acrylamide, acrylic, allyl or maleic), these monomers having a phosphonium or quaternary ammonium function.

[0102] Mention may be made, in particular and in a non-limiting manner, of diallyldialkyl ammonium salts such as diallyl dimethyl ammonium chloride (DADMAC); acidified or quaternized salts of dialkylaminoalkylacrylamides; acidified or quaternized salts of dialkylaminoalkylmethacrylamides, such as for example methacrylamidopropyl trimethyl ammonium chloride (MAPTAC), acrylamidopropyl trimethyl ammonium chloride (APTAC), acidified or quaternized salts of dialkyl aminoalkyl acrylate such as quaternized or salified dimethylaminoethyl acrylate (ADAME), acidified or quaternized salts of dialkyl aminoalkyl methacrylate such as quaternized or salified dimethylaminoethyl methacrylate (MADAME) and mixtures thereof. Advantageously, the alkyl groups are C1-C3.

[0103] A person skilled in the art will know how to prepare the quaternized monomers, for example using a quaternizing agent of the RX type, R being an alkyl group and X being a halogen or a sulfate.

[0104] By “quaternizing agent” we mean a molecule capable of alkylating a tertiary amine.

[0105] The quaternizing agent may be chosen from dialkyl sulfates comprising from 1 to 6 carbon atoms or alkyl halides comprising from 1 to 6 carbon atoms. Preferably, the quaternizing agent is chosen from methyl chloride, benzyl chloride, dimethyl sulfate or diethyl sulfate. In addition, the present invention also covers monomers of the DADMAC, APTAC and MAPTAC type whose counterion is a sulfate, a fluoride, a bromide or an iodide instead of the chloride.

[0106] The zwitterionic monomers are preferably chosen from derivatives having a vinyl-type unit, in particular acrylamide, acrylic, allyl or maleic. Preferably, this monomer comprises an amine or quaternary ammonium function and an acid function of carboxylic (or carboxylate), sulfonic (or sulfonate) or phosphoric (or phosphate) type.Mention may be made in particular and in a non-limiting manner of dimethylaminoethyl acrylate derivatives, such as -2 - ((2-9 (acryloyloxy) ethyl) dimethylammonio) ethane-1-sulfonate, -3 - ((2- (acryloyloxy) ethyl) dimethylammonio) propane-1-sulfonate, -4 - ((2- (acryloyloxy) ethyl) dimethylammonio) butane-1-sulfonate, [2-(acryloyloxy) ethyl] (dimethylammonio) acetate, dimethylaminoethyl methacrylate derivatives such as -2 - ((2- (methacryloyloxy) ethyl) dimethylammonio) ethane-1-sulfonate, -3 - ((2- (methacryloyloxy) ethyl) dimethylammonio) propane-1-sulfonate, -4 - (-2 - (methacryloyloxy) ethyl) dimethylammonio) butane- . 1-sulfonate, [2- (methacryloyloxy) ethyl] (dimethylammonio) acetate, dimethylamino propylacrylamide derivatives such as -2 - ((3-acrylamidopropyl) dimethylammonio) ethane-1-sulfonate, -3 - ((3-acrylamidopropyl) dimethylammonio) propane-1-sulfonate, -4 - ((3-acrylamidopropyl) dimethylammonio) butane-1-sulfonate, [3- (acryloyl) oxy) propyl] (dimethylammonio) acetate, dimethylamino propyl methylacrylamide, -2 - ((3-methacrylamidopropyl) dimethylammonio) ethane-1-sulfonate, -3 - (dimethylammonio) propane-1-sulfonate-4 - ((3-methacrylamidopropyl) dimethylammonio) butane-1-sulfonate, propyl [3-(methacryloyloxy)] (dimethylammonio) acetate; and mixtures thereof.

[0107] Other zwitterionic monomers are described by the Applicant in document WO21123599.

[0108] Preferably, A is a monomeric unit or a linear or structured polymer chain characterized in that the monomer(s) of the monomeric unit or of the polymer chain are chosen from; acrylamide, acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS) and / or one of its salts, N-vinylformamide (NVF), N-vinylpyrrolidone (NVP), dimethyldiallylammonium chloride (DADMAC), quaternized dimethylaminoethyl acrylate (ADAME), quaternized dimethylaminoethyl methacrylate (MADAME), itaconic acid

[0109] Preferably, Q is a monomeric unit or a linear or structured polymer chain characterized in that the monomer(s) of the monomeric unit or of the polymer chain are chosen from; glycidyl methacrylate, methacrylate, maleic anhydride, itaconic anhydride, hydroxy(alkyl)acrylate, glycidyl acrylate, allyl glycedyl ether, allyl(meth)acrylate.

[0110] Preferably, the oligo-initiator is of formula (I) in which: [YES] Z = O and ;

[0112] R1 and R2 represent an optionally substituted alkyl, acyl, aryl, alkene or alkyne group, and

[0113] A is a monomeric unit or a linear or structured polymer chain comprising from 1 to 300 monomeric units preferably chosen from; acrylamide, acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS) and / or one of its salts, N-vinylformamide (NVF), N-vinylpyrrolidone (NVP), dimethyldiallylammonium chloride (DADMAC), quaternized dimethylaminoethyl acrylate (ADAME), quaternized dimethylaminoethyl methacrylate (MADAME), itaconic acid

[0114] Q is a monomeric unit or a linear or structured polymer chain comprising from 1 to 500 monomeric units preferably chosen from; glycidyl methacrylate, methacrylic anhydride, maleic anhydride, itaconic anhydride, hydroxy(alkyl)acrylate, glycidyl acrylate, allyl glycedyl ether, 1' allyl(meth)acrylate.

[0115] According to a preferred embodiment of the invention, the oligo-initiator is of the following formula (II):

[0116] [Chem.2]

[0117] (II)

[0118] wherein nA acrylamide unit is between 1 and 300, and nQ glycidyl methacrylate unit is between 1 and 500.

[0119] According to a second preferred embodiment of the invention, the oligo-initiator is of the following formula (III):

[0120] [Chem.3]

[0121] (III)

[0122] wherein nA itaconic acid unit is between 1 and 300, and nQ itaconic anhydride unit is between 1 and 500.

[0123] Another aspect of the present invention is to provide the method of synthesizing such an oligo-initiator.

[0124] The oligo-initiator is obtained by radical polymerization. By radical polymerization, we include polymerization by means of photochemical (UV or radiation), azo, thermal, or redox salt initiators, as well as controlled radical polymerization (PCR) techniques or matrix polymerization techniques.

[0125] As a controlled radical polymerization technique, we can cite, in a non-limiting manner, techniques such as iodine transfer polymerization (ITP), polymerization controlled by ni- troxides, ("Nitroxide Mediated Polymerization" in English (NMP)), by atom transfer ("Atom Transfer Radical Polymerization" in English (ATRP)), by reversible addition-fragmentation chain transfer ("Reversible Addition Fragmentation chain Transfer Polymerization" in English (RAFT)), which includes the MADIX technology ("MAcromolecular Design by Interchange of Xanthates" in English), various variations of polymerizations with organometallic compounds ("Organometallic Mediated Radical Polymerization" in English (OMRP)), radical polymerization controlled by heteroatomic compounds (“OrganoHeteroatom-mediated Radical Polymerization” in English (OHRP)).

[0126] In a preferred embodiment, the polymerization is carried out by reversible addition-fragmentation chain transfer (“Reversible Addition Fragmentation chain Transfer Polymerization” in English (RAFT)).

[0127] The oligo-initiator is preferentially obtained by reacting at least one molecule of formula (IV), with at least one monomer chosen from those having at least one reactive functional group (frQ), previously described, and at least one hydrophilic monomer comprising at least one unsaturated ethylenic function previously cited, the formula (IV) being the following:

[0128] [Chem.4] 'C — S — R 2 R* -- Z

[0129] (IV)

[0130] Following this reaction, the oligo-initiator comprises at least one reactive functional group (frQ), capable of reacting with complementary functional groups.

[0131] The polymerization initiators advantageously used may be chosen from compounds which dissociate into radicals under the polymerization conditions, for example: organic peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds and redox catalysts. The use of water-soluble initiators is preferred. In some cases, it is advantageous to use mixtures of various polymerization initiators, for example mixtures of redox salts and azo compounds.

[0132] Advantageously, the quantity of initiator is between 5 and 1,000 ppm, preferably between 10 and 500 ppm, more preferably between 20 and 100 ppm, relative to the total weight of the polymerization charge.

[0133] Said initiator can be added in one go to the reaction medium, by pouring, or discontinuously into the medium.

[0134] The oligo-initiator can be prepared in the form of a suspension or solution in water, in a solvent, alone or in a mixture with water, in particular an alcoholic solvent such as methanol, ethanol, isopropanol. Preferably, the oligo-initiator is prepared in water.

[0135] Preferably the oligo-initiator is prepared at a temperature between 5 and 100°C, preferably between 10 and 80°C, more preferably between 15 and 75°C.

[0136] Advantageously, the synthesis of this oligo-initiator takes place over a period of 1 to 12 hours, preferably 1 to 5 hours. It is preferably carried out at atmospheric pressure.

[0137] The invention also relates to the use of the oligo-initiator according to the invention for producing water-soluble polymers, preferably water-soluble hybrid polymers.

[0138] According to one aspect of the present invention, the oligo-initiator is advantageously used in the synthesis of water-soluble hybrid polymer.

[0139] According to this aspect of the present invention, a water-soluble hybrid polymer PH is obtained by functionalization of a biopolymer B1 with an oligo-initiator of general formula (I) previously described, then polymerization of at least one hydrophilic monomer having at least one unsaturated ethylenic function.

[0140] Biopolymer B1

[0141] The biopolymer Bi is a polymer derived from natural and / or renewable resources, that is to say derived from living organisms or synthesized from renewable resources.

[0142] Preferably, the biopolymer Bi according to the invention is soluble in water. By soluble in water, this means soluble over the entire pH scale of water, this includes biopolymers, such as chitosan which is soluble in acidified water. An insoluble biopolymer can also be used after treatment of the latter to make it soluble, according to techniques known to those skilled in the art.

[0143] According to the present invention, the biopolymer bisynthesized from renewable resources may be, without limitation, a biopolymer resulting from the hydrolysis and / or fermentation of products from renewable resources.

[0144] For example, this includes products from polycondensation such as polyesters, phenolic derivatives such as tannins or lignin or products from biomass fermentation such as microbial polymers: itaconic acid polymer from hemicellulose fermentation, polyhydroxyalkanoate (PHA), xanthan, pullulan, lactic acid polymer, glycolic acid polymer, succinic acid or polyesters, polyhydroxybutyrate.

[0145] As used herein, the term "biopolymer" includes both; native biopolymers or natural, biopolymers obtained synthetically from natural compounds, biopolymer derivatives and modified biopolymers. By "modified biopolymers" this means a native biopolymer that has undergone one or more treatments. These treatments may be physical and / or chemical and / or enzymatic in nature.

[0146] According to the present application, the biopolymer Bi from living organisms is preferentially chosen from polysaccharides or proteins.

[0147] The proteins are obtained by conventional methods known to those skilled in the art, for example by dissolution, grinding, screening and classification.

[0148] The protein(s) according to the invention may be of animal origin. Among the animal proteins that may be cited by way of example: milk proteins such as [3-lactoglobulin, casein, whey; serum proteins such as horse serum; fibrous dermal proteins such as collagen, elastin, silk proteins.

[0149] The protein(s) according to the invention may be of plant origin, such as corn, wheat, barley and oats, soybean, pea, for example glutelin, prolamin, zein and gluten. Advantageously, the plant proteins are chosen from soybean proteins, wheat proteins, oat proteins, pea proteins. The proteins may be obtained from seeds, for example soybeans, cotton seeds, peanuts, sunflower, rapeseed, coconut, flax seeds, sesame, saflour, peas, beans or lentils.

[0150] Other sources of protein are bacteria, fungi, algae and yeasts, e.g. Pseudomonas, Lactobacillus, Penicillium, E.Coli, blue algae, green algae, Chlorella, Spirulina and excess yeasts.

[0151] Preferably, the protein chosen will be a casein, a serum protein or wheat protein.

[0152] To convert proteins into a soluble form, it is often necessary to carry out digestion by physical, chemical or enzymatic treatment, for example, hydrolysis with acid or alkali, fermentation with yeasts, bacteria or enzymes, extraction methods to remove minor constituents, coagulation from extracts by heating, addition of an electrolyte, adjustment of pH or addition of precipitants. Pure products can be prepared, for example, by fractional dissolution and precipitation or by dialysis.

[0153] The proteins may be present in the form of a mixture. This means a mixture containing several proteins originating from the same living kingdom or from a different kingdom. For example, a mixture containing several proteins of animal origin, or a mixture containing at least one protein of animal origin and at least one protein of plant origin and / or one protein of bacterial origin.

[0154] Polysaccharides can be extracted from plants, produced by micro-or organisms such as bacteria, fungi, prokaryotes, eukaryotes, extracted from animals and / or humans. For example, xanthan gum can be produced by Xanthomonas campestris, gellan by Sphingomonas paucimobllis, xyloglucan can be extracted from tamarind seeds.

[0155] Preferably, the polysaccharide is selected from the group consisting of: tamarind gum (preferably made from xyloglucan polymers), guar gum, locust bean gum (preferably made from galactomannan polymers), and other industrial gums and polymers, which include, but are not limited to, tara gum, fenugreek, aloe, chia, flax seed, psyllium seed, quince seed, xanthan, gellan, welan, rhamsan, dextran, curdlan, pullulan, scleroglucan, schizophyllan, chitin, hydroxyalkylcellulose, arabin (preferably from sugar beets), arabinoxylan, galactan (preferably from lupin and potatoes), pectic galactan (preferably from potato), galactomannan (preferably from carob, and including both low and high viscosities), glucomannan, lichenan (preferably from Iceland moss), mannan (preferably from ivory nut), pachyman, rhamnogalacturonan,acacia gum, agar, alginates, carrageenan, chitosan, clavane, hyaluronic acid, heparin, inulin, cellodextrins, cellulose, cellulose derivatives and mixtures thereof.

[0156] The polysaccharide may be linear, such as hydroxyalkylcellulose, it may have an alternating repeat such as carrageenan, it may have an interrupted repeat such as pectin, it may be a block copolymer such as alginate, it may be branched such as dextran, or it may have a complex repeat such as xanthan. Polysaccharides are described in "An introduction to Polysaccharide Biotechnology", by M. Tombs and SE Harding, TJ Press 1998.

[0157] The polysaccharide(s) may be modified with amines (primary, secondary, tertiary), amides, esters, ethers, methanes, alcohols, carboxylic acids, tosylates, sulfonates, sulfates, nitrates, phosphates and mixtures thereof. Such modification may take place at position 2, 3 and / or 6 of the saccharide unit. These modified or derived polysaccharides may be included in the present invention in addition to natural polysaccharides.

[0158] Non-limiting examples of such modified polysaccharides include: carboxyl and hydroxymethyl substitutions (e.g., glucuronic acid instead of glucose); amino polysaccharides (amine substitution, e.g., glucosamine instead of glucose); Cr-C6 alkylated polysaccharides; acetylated polysaccharide ethers; polysaccharides with attached amino acid residues (small glycoprotein fragments); polysaccharides containing silicone groups. Suitable examples of such modified polysaccharides are commercially available from Carbomer and include, among others, Amino alginates, such as hexanediamine alginate, amine-functionalized cellulose, such as O-methyl-(Nl,12-dodecanediamine) cellulose, biotin heparin, carboxymethylated dextran, guar polycarboxylic acid, carboxymethylated carob, carboxymethylated locust bean gum, carboxymethylated xanthan, chitosan phosphate, chitosan phosphate sulfate, diethylaminoethyl dextran, dodecylamide alginate, sialic acid, glucuronic acid, galacturonic acid, mannuronic acid, guluronic acid, N-acetylgluosamine, N-acetylgalactosamine, and mixtures thereof.

[0159] Preferably, the polysaccharide is selected from the group consisting of chitosan, xanthan gum, fenugreek gum, tara gum, locust bean gum, carrageenan, guar gum, alginate, agar, tragacanth gum, tamarind gum, gum arabic, cherry gum, karaya gum, okra gum, cassia gum, chicle gum, konjac gum, glucomannan, gum ghatti, pectin, sclerotium gum, gellan gum, derivatives thereof and combinations thereof. Chemically modified versions of these polymers may also be used.

[0160] Even more preferably, the particularly preferred polysaccharides are cellulose, and the ether, carboxy, methyl, hydroxy methyl, ester and urethane derivatives of cellulose.

[0161] According to a preferred embodiment, the biopolymer Bi is a polysaccharide, preferentially chosen from: starch or its derivatives such as carboxymethyl starch; cellulose or its derivatives such as carboxymethylcellulose, hemicellulose; polysaccharides extracted from algae such as agarose, carrageenans, alginates; pectins; inulin; guar gums; konjac gum; dextran; pullulan; gellan; curdlan.

[0162] Even more preferably the polysaccharides will be chosen from starch derivatives and / or cellulose derivatives. Even more preferably the polysaccharide is a carboxymethylcellulose and / or a carboxymethyl starch.

[0163] According to the present invention, the native or modified Bi biopolymer comprises at least one reactive functional group (frB) of hydroxy and / or carboxy and / or anhydride and / or amine and / or amide and / or vinyl type, and / or phosphate and / or sulfonate and / or ester and / or aldehyde and / or ketone and / or silane, and / or isocyanate and / or nitrile and / or acyl halide.

[0164] More preferably, the reactive functional group (frB) is a hydroxy, carboxylate, or anhydride group. In other words, the biopolymer Bi comprises at least one reactive functional group (frB) chosen from hydroxy, carboxylate, or anhydride functions.

[0165] The functional group(s) (frB) are in the form of side groups pendants.

[0166] According to a preferred embodiment, these reactive functional groups (frB) are neutralized using a base before and / or during the polymerization of the synthetic side chains L during step 2. The base is chosen from bases comprising an ion chosen from the group consisting of Li+, Na+, K+, Ca++, Mg++, Zn++, Al+++ or mixtures thereof; preferably the base is chosen from hydroxides, carbonates and hydrogen carbonates comprising an ion chosen from Li+, Na+, K+, Ca++, Mg++, Zn++, Al+++ or mixtures thereof.

[0167] Without being bound by any theory, the Applicant has discovered that the presence of free carboxylate function on the biopolymer Bi allows better reactivity of these free hydroxyl functions, allowing a covalent bond with the optimized oligo-initiator to thus form the functionalized biopolymer B2. ([Fig.l])

[0168] Water-soluble hybrid polymer PH obtained by using the oligo-initiator according to a process comprising at least the following successive steps: 1. Functionalization of a biopolymer Bi by reaction of at least one of its reactive functional groups (frB) with at least one reactive functional group (frQ) of said oligo-initiator, to obtain a functionalized biopolymer B2, 2. Polymerization of hydrophilic monomers comprising at least one ethylenic unsaturation on at least one oligo-initiator of the functionalized biopolymer B2 to form at least one side chain L, and thus obtain the hybrid polymer PH,

[0169] Step (1) - functionalization of a Biopolymer Bi with an oligo-initiator according to the invention to obtain a Biopolymer B2

[0170] In step (1) of the process according to the invention, the biopolymer B2 is obtained by functionalization of the biopolymer Bi with at least one oligo-initiator according to the invention, by reaction of at least one of the reactive functional groups (frB) of the biopolymer Bi with at least one reactive functional group (frQ) of said oligo-initiator.

[0171] Biopolymer B2 thus corresponds to biopolymer Bi after functionalization of the latter with the oligo-initiator.

[0172] The percentage of reactive functions (frB) substituted by the oligo-initiator in the biopolymer B2 is between 0.1 and 90%, preferably between 0.1 and 50%, even more preferably between 0.1 and 25%.

[0173] Said biopolymer B2 preferably has a mass ratio (Bi / Oligo-initiator) of between 50 / 50 and 97 / 3.

[0174] The functionalization reaction is carried out by bringing the biopolymer Bi and at least one oligo-initiator into contact under the appropriate conditions described below.

[0175] The oligo-initiator can be added continuously into the solution, by static mixer or dynamic or in a microreactor. The skilled person knows the different appropriate addition methods.

[0176] One aspect of the present invention is based on the so-called "gentle" conditions for obtaining said biopolymer B2. Indeed, the functionalization reaction is preferably carried out without solvents harmful to humans and the environment. It is preferably carried out without the use of a catalyst. It is preferably carried out without a purification step.

[0177] The biopolymer B2 may be solubilized prior to its functionalization or not.

[0178] Preferably, the biopolymer B2 is prepared in aqueous solution. Very preferably the only solvent used is water. The reaction temperature is preferably between 5 and 85°C, preferably between 10 and 70°C, more preferably between 15 and 65°C.

[0179] Advantageously, the functionalization reaction of the biopolymer B2 takes place over a period of 1 to 12 hours, preferably 1 to 5 hours. It preferably takes place at atmospheric pressure.

[0180] Step (2) - Polymerization to obtain synthetic side chains L

[0181] During step (2), the hydrophilic monomers polymerize preferentially by inserting themselves between the thiol function and A, or Q (if =0), of the part corresponding to the oligo-initiator.

[0182] Step (2) consists of the polymerization of hydrophilic monomers comprising at least one ethylenic unsaturation on at least one oligo-initiator of the functionalized biopolymer B2 to form at least one side chain L, and thus obtain the hybrid polymer PH.

[0183] In step (2) according to the invention, the polymerization of hydrophilic monomers comprising at least one ethylenic unsaturation is carried out on the oligo-initiator of the functionalized biopolymer B2,

[0184] Hydrophilic monomers polymerize preferentially by inserting themselves between the thiol function and A, or Q (if =0), of the part corresponding to the oligo-initiator.

[0185] Thus, it is expected that as many synthetic side chains L are present as there are bonds between the polymer chain of the biopolymer B2 and the oligo-initiator, corresponding to the number of sites (frB-frQ) on the functionalized biopolymer B2

[0186] In other words, if only one bond between the functionalized biopolymer B2 and the oligo-initiator is present then there will only be one synthetic side chain L. If there are two bonds between the functionalized biopolymer B2 and the oligo-initiator then there will be two synthetic side chains L. If there are three bonds between the functionalized biopolymer B2 and the oligo-initiator then there will be three synthetic side chains L, etc.

[0187] Advantageously, said synthetic side chains L are obtained by poly radical polymerization. By radical polymerization, we include polymerization using photochemical (UV or radiation), azo, thermal, or redox salt initiators, as well as controlled radical polymerization (PCR) techniques or matrix polymerization techniques.

[0188] As a controlled radical polymerization technique, we can cite, in a non-limiting manner, techniques such as iodine transfer polymerization (ITP), nitroxide-mediated polymerization (NMP), atom transfer (ATRP), reversible addition-fragmentation chain transfer (RAFT), which includes MADIX technology (MAcromolecular Design by Interchange of Xanthates), various variations of polymerizations with organometallic compounds. ("Organometallic Mediated Radical Polymerization" in English (OMRP)), radical polymerization controlled by heteroatomic compounds (“OrganoHeteroatom-mediated Radical Polymerization” in English (OHRP)).

[0189] In a preferred embodiment, the polymerization is carried out by reversible addition-fragmentation chain transfer (RAFT) of at least one hydrophilic monomer comprising at least one ethylenic unsaturation (double bond between two carbon atoms).

[0190] The polymerization reaction of step (2) corresponds to the formation and extension of the polymer chain on the oligo-initiator, preferably by fragmentation and addition of monomeric units. The hydrophilic monomers polymerize preferentially by inserting themselves between the thiol function and A, or Q (if nA = 0), of the part corresponding to the oligo-initiator.

[0191] The polymerization reaction of step (2) is carried out in the following manner: the functionalized biopolymer B2 is mixed, preferably by continuous casting of the hydrophilic monomers comprising at least one ethylenic unsaturation, then the polymerization is triggered.

[0192] Preferably, the polymerization reaction is carried out in an aqueous medium, very preferably in water. The reaction temperature is preferably between 5 and 100°C, preferably between 10 and 70°C, more preferably between 15 and 65°C.

[0193] Advantageously, the polymerization reaction takes place over a period of 1 to 12 hours, preferably 2 to 7 hours. It preferably takes place at atmospheric pressure.

[0194] The hydrophilic monomers are preferably chosen from non-ionic monomers and / or anionic monomers and / or cationic monomers and / or zwitterionic monomers.

[0195] Advantageously, the hydrophilic non-ionic monomer(s) which may be used in the context of the invention are chosen, in particular, from the group comprising water-soluble vinyl monomers, such as acrylamide, methacrylamide, N-alkylacrylamides, N-alkylmethacrylamides, N,N-dialkyl acrylamides (for example N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N-dialkylmethacrylamides, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylolacrylamide, N-vinylformamide (NVF), N-vinyl acetamide, N-vinyl imidazole, N-vinyl suc-cinimide, acryloyl morpholine (ACMO), acryloyl chloride, glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, hydroxyalkyl (meth)acrylate, aminoalkyl (meth)acrylate, thioalkyl (meth)acrylate, hydroxyalkylacrylates, hydroxyalkyl methacrylates, and mixtures thereof.Among these non-ionic monomers, the alkyl groups are advantageously C1-C5, more advantageously C1-C3. These are preferably linear alkyls.

[0196] Advantageously, the hydrophilic anionic monomer(s) that can be used in the context of the invention can be chosen from a broad group. These monomers can have vinyl functions (advantageously acrylic, maleic, fumaric, malonic, itaconic, or allylic), and contain a carboxylate, phosphonate, phosphate, sulfate, sulfonate group, or another group with anionic charge.Examples of suitable monomers include acrylic acid; methacrylic acid; dimethylacrylic acid; itaconic acid; crotonic acid; maleic acid; fumaric acid; acrylamido undecanoic acid; 3-acrylamido 3-methylbutanoic acid; maleic anhydride; strong acid monomers having for example a sulfonic acid or phosphonic acid function such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-1,3-disulfonic acid, 2-sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), 2-acrylamido-2-methylpropane disulfonic acid; water-soluble salts of these monomers such as their alkali metal, alkaline earth metal, or ammonium salts; and mixtures thereof.Preferably, the hydrophilic anionic monomer(s) is acrylic acid and / or its salts.

[0197] In a particular embodiment of the invention, the anionic monomer(s) may be salified. It may also be a mixture of acid form and salified form, for example a mixture of acrylic acid and acrylate.

[0198] By salified is meant the substitution of a proton of at least one acid function of the type -R(=O)-OH (with R= P, S or C) of the anionic monomer by a metal cation or ammonium to form a salt of the type -R(=O)-OX (X being a metal or ammonium cation). In other words, the non-salified form corresponds to the acid form of the monomer, for example RC(=O)-OH in the case of the carboxylic acid function, while the salified form of the monomer corresponds to the form RC(=O)-O- X+, X+ corresponding to an alkali or ammonium cation. The salification of the acid functions of the water-soluble polymer can be partial or total.

[0199] The salified form advantageously corresponds to the salts of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium (for example the ammonium ion or a tertiary ammonium). The preferred salts are the sodium salts.

[0200] The salification can be carried out before, during or after the polymerization of step (2).

[0201] Advantageously, the hydrophilic cationic monomer(s) which can be used in the context of the invention are chosen from monomers derived from vinyl type units (advantageously acrylamide, acrylic, allyl or maleic), these monomers having a phosphonium or quaternary ammonium function.

[0202] Mention may be made, in particular and in a non-limiting manner, of diallyldialkyl ammonium salts such as diallyl dimethyl ammonium chloride (DADMAC); acidified or quaternized salts of dialkylaminoalkylacrylamides; acidified or quaternized salts of dialkylaminoalkylmethacrylamides, such as for example methacrylamidopropyltrimethylammonium chloride (MAPTAC), acrylamidopropyltrimethylammonium chloride (APTAC), acidified or quaternized salts of dialkylaminoalkyl acrylate such as quaternized or salified dimethylaminoethyl acrylate (ADAME), acidified or quaternized salts of dialkylaminoalkyl methacrylate such as quaternized or salified dimethylaminoethyl methacrylate (MADAME) and mixtures thereof. Advantageously, the alkyl groups are C1-C3.

[0203] A person skilled in the art will know how to prepare the quaternized monomers, for example using a quaternizing agent of the RX type, R being an alkyl group and X being a halogen or a sulfate.

[0204] By “quaternizing agent” we mean a molecule capable of alkylating a tertiary amine.

[0205] The quaternizing agent may be chosen from dialkyl sulfates comprising from 1 to 6 carbon atoms or alkyl halides comprising from 1 to 6 carbon atoms. Preferably, the quaternizing agent is chosen from methyl chloride, benzyl chloride, dimethyl sulfate or diethyl sulfate. In addition, the present invention also covers monomers of the DADMAC, APTAC and MAPTAC type whose counterion is a sulfate, a fluoride, a bromide or an iodide instead of the chloride.

[0206] Advantageously, the hydrophilic zwitterionic monomer(s) may be a derivative of a vinyl-type unit (advantageously acrylamide, acrylic, allylic or maleic), this monomer having an amine or quaternary ammonium function and an acid function of the carboxylic (or carboxylate), sulfonic (or sulfonate) or phosphoric (or phosphate) type. Mention may be made, in particular and without limitation, of derivatives of dimethylaminoethyl acrylate, such as 2-((2-(acryloyloxy)ethyl) di-methylammonio) ethane-1-sulfonate, 3-((2-(acryloyloxy)ethyl) dimethylammonio) propane-1-sulfonate, 4-((2-(acryloyloxy)ethyl) dimethylammonio) butane-1-sulfonate, [2-(acryloyloxy)ethyl] (dimethylammonio) acetate, derivatives of dimethylaminoethyl methacrylate such as 2-((2-(methacryloyloxy)ethyl) dimethylammonio) ethane-1-sulfonate, 3-((2-(methacryloyloxy)ethyl) dimethylammonio) propane-1-sulfonate, 4-((2-(methacryloyloxy)ethyl) dimethylammonio) butane-1-sulfonate, [2-(methacryloyloxy)ethyl] (dimethylammonio) acetate,dimethylamino propylacrylamide derivatives such as 2-((3-acrylamidopropyl) dimethylammonio) ethane-1-sulfonate, 3-((3-acrylamidopropyl) dimethylammonio) propane-1-sulfonate, 4-((3-acrylamidopropyl) dimethylammonio) butane-1-sulfonate, [3-(acryloyloxy)propyl] (dimethylammonio) acetate, dimethylamino propyl methylacrylamide derivatives such as 2-((3-methacrylamidopropyl) dimethylammonio) ethane-1-sulfonate, 3-((3-methacrylamidopropyl) dimethylammonio) propane-1-sulfonate, 4-((3-methacrylamidopropyl) dimethylammonio) butane-1-sulfonate and [3-(methacryloyloxy)propyl] (dimethylammonio) acetate and mixtures thereof. ,

[0207] The side chain(s) L have a weight-average molecular weight of between 5,000 and 1,000,000 Da, preferably between 10,000 and 800,000 Da, even more preferably between 20,000 and 500,000 Da.

[0208] According to another embodiment of the invention, the polymerization may be a radical polymerization by ring opening, this polymerization being able to be of the RAFT type.

[0209] Ring-opening polymerization (ROP) is a polymerization process in which polymerization occurs as a result of the opening of a ring of a cyclic monomer. It can be ionic or free-radical polymerization.

[0210] Ring-opening radical polymerization (rROP), implemented for cyclic monomers, combines the advantages of ring-opening polymerization and radical polymerization. It is thus possible to prepare polymers carrying heteroatoms in the backbone (main polymer chain), while benefiting from the ease and robustness of a radical polymerization process.

[0211] In this case, the cyclic monomer(s) which can be used in the context of the invention, in addition to the hydrophilic monomers comprising at least one ethylenic unsaturation, can be chosen from: cyclic ketene acetals, or thiono-lactones or their mixtures.

[0212] The cyclic ketene acetal is advantageously chosen from the following compounds: 2-methylene-1,3-dioxepane (MDO), 5,6-benzo-2-methylene-1,3-dioxepane (BMDO), 2-methylene-4-phenyl-1,3-dioxolane (MPDL), 2-methylene-1,3,6-trioxocane (MTC), and mixtures thereof. Preferably, it is 2-methylene-1,3-dioxepane (MDO).

[0213] Advantageously, the amount of cyclic ketene acetal in the side chain L is between 5 and 30 mol%, relative to the total amount of monomers in the side chain L, preferably between 5 and 20 mol%.

[0214] The thionolactone is advantageously chosen from: Dibenzo[c,e]oxepine(7H)-5-thione (DOT), e-thionocaprolactone, 3,3-dimethyl-2,3-dihydro-5Hbenzo[e][l,4]dioxepine-5-thione (DBT) and mixtures thereof. Preferably, it is 3,3-dimethyl-2,3-dihydro-5Hbenzo[e][1,4]dioxepine-5-thione.

[0215] Advantageously, the quantity of thionolactones in the side chain L is between 2 and 20 mol%, relative to the total quantity of monomer present in the side chain L, preferably between 5 and 15 mol%.

[0216] Advantageously, the quantity of hydrophilic monomers comprising at least one ethylenic unsaturation in the side chain L is between 50 mol% and 93 mol%, preferably between 65 mol% and 90 mol%.

[0217] According to this embodiment, the synthetic side chains L are preferentially obtained by radical polymerization of at least two monomers: - at least one hydrophilic monomer comprising at least one ethylenic unsaturation chosen from non-ionic monomers, anionic monomers, cationic monomers, zwitterionic monomers; - at least one cyclic monomer chosen from cyclic ketene acetals, thionolactones and their mixtures;

[0218] The PH hybrid polymer

[0219] According to the present invention, a water-soluble hybrid polymer PH is obtained according to the method described above, namely by functionalization of a biopolymer B1 with an oligo-initiator of general formula (I) according to the invention, then polymerization of at least one hydrophilic monomer having at least one unsaturated ethylenic function.

[0220] The same preferences as those described previously in the other parts apply in this part concerning the PH hybrid polymer, in particular the preferences relating to the oligo-initiator.

[0221] The water-soluble hybrid polymer is preferably obtained with an oligo-initiator of formula (I) with:

[0222] Z=O,

[0223] R1 and R2 represent an alkyl, acyl, aryl, alkene or alkyne group optionally substituted,

[0224] A is a monomeric unit or a linear polymer chain comprising ra 1 to 300 monomeric units;

[0225] Q is a monomeric unit or a linear polymer chain comprising nQ 1 to 500 monomeric units.

[0226] The hybrid polymer PH consists of a skeleton formed by the biopolymer B2 on which synthetic side polymer chains L are covalently bonded. ([Fig.l] and [Fig.2]).

[0227] The water-soluble hybrid polymer PH according to the invention is characterized in that the monomer(s) of the monomeric unit or of the polymer chain A are chosen from; acrylamide, acrylic acid, an oligomer of acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS) and / or one of its salts, N-vinylformamide (NVF), N-vinylpyrrolidone (NVP), dimethyldiallylammonium chloride (DADMAC), quaternized dimethylaminoethyl acrylate (ADAME), quaternized dimethylaminoethyl methacrylate (MADAME).

[0228] In the water-soluble hybrid polymer PH the percentage of reactive functions (frB) substituted by the oligo-initiator in the biopolymer B2 is preferably between 0.1 and 90%.

[0229] According to the invention, the biopolymer Bi used to produce the hybrid polymer PH, preferably comprises at least one reactive functional group (frB) chosen from hydroxy, carboxylate or anhydride functions.

[0230] The biopolymer Bi is preferably a polysaccharide. The biopolymer Bi is more preferably a polysaccharide chosen from: starch; cellulose, cellulose sulfate, cellulose acetate, sulfoethylcellulose, cyanoethylcellulose, methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxyethylcellulose or hydroxypropylcellulose, hemicellulose; xyloglucans, glucomannans, galactomannans, chitosan and chitosan salts; polysaccharides extracted from algae such as agarose, carrageenans, alginates; pectins; dextran; pullulan; gellan; and combinations thereof.

[0231] In the water-soluble hybrid polymer PH, the side chain(s) L preferably have a weight-average molecular weight of between 5,000 and 1,000,000 Da.

[0232] Said hybrid polymer PH can be easily isolated using the usual separation, precipitation, evaporation and / or drying methods known to those skilled in the art. The solvent, preferably water, can be extracted by filtration or distillation, advantageously by distillation.

[0233] The water-soluble hybrid polymer PH can be obtained and used in liquid form, i.e. in solution (emulsion, aqueous solution, water-in-water dispersion) or in particulate form (powder, microbeads, aqueous or oily dispersions, ag fine glomerates). Advantageously, the water-soluble hybrid polymer PH is used in liquid form.

[0234] The powder form of the water-soluble hybrid polymer PH can be obtained by polymerization in aqueous solution followed by drum drying or spray drying or radiation drying such as microwave drying or drying in a fluidized bed. The powder form can also be obtained by water-in-oil emulsion (inverse emulsion), emulsion or dispersion polymerization followed by a distillation / concentration step and spray drying of the resulting liquid.

[0235] The polymer according to the invention may have a weight average molecular weight covering all applications in which synthetic water-soluble polymers may be used. Thus, the PH hybrid polymer according to the invention may have a weight average molecular weight of between 50,000 and 100,000 g / mol, or between 100,000 and 500,000 g / mol, or between 500,000 and 1,000,000 g / mol, or between 1,000,000 and 3,000,000 g / mol, or between 3,000,000 and 5,000,000 g / mol, or between 5,000,000 and 10,000,000 g / mol, or between 10,000,000 and 30,000,000 g / mol, or even greater than 30,000,000 g / mol. This is the weight average molecular weight.

[0236] The molecular weight is advantageously determined from the intrinsic viscosity of the polymer. The intrinsic viscosity can be measured by methods known to those skilled in the art and can be calculated from the reduced viscosity values ​​for different polymer concentrations by a graphical method consisting of plotting the reduced viscosity values ​​(y-axis) on the concentration (x-axis) and extrapolating the curve to zero concentration. The intrinsic viscosity value is plotted on the y-axis or using the least squares method. The molecular weight can then be determined by the Mark-Houwink equation:

[0237] [q] = K Ma

[0238] [q] represents the intrinsic viscosity of the polymer determined by the method of measurement of viscosity in solution.

[0239] K represents an empirical constant.

[0240] M represents the molecular weight of the polymer.

[0241] a represents the Mark-Houwink coefficient.

[0242] K and a depend on the particular polymer-solvent system.

[0243] Use of the PH hybrid polymer

[0244] The present invention also relates to the use of the water-soluble hybrid polymer PH according to the invention in the recovery of hydrocarbons (oil or gas); well drilling; well cementing; stimulation of hydrocarbon wells (oil or gas), for example hydraulic fracturing, conformation, diversion ; open, closed or semi-closed circuit water treatment; fermentation must treatment; sludge treatment; construction; paper or cardboard manufacturing; battery industry; wood processing; hydraulic composition processing (concrete, cement, mortar and aggregates); in the mining industry; cosmetic product formulation; detergent formulation; textile manufacturing; geothermal energy; or agriculture.

[0245] Finally, the present invention also relates to the use of the water-soluble hybrid polymer PH according to the invention as a flocculant, coagulant, dispersant, binding agent, fixing agent, viscosity reducing agent, thickening agent, absorbent agent, friction reducing agent, drainage agent, charge retention agent, dehydration agent, conditioning agent, stabilizing agent, film-forming agent, sizing agent, clay inhibitor. EXAMPLES

[0246] The following examples best illustrate the advantages of the invention in a clear and non-limiting manner.

[0247] The following abbreviations are used.

[0248] AA: acrylic acid.

[0249] AANa: neutralized acrylic acid.

[0250] AM: acrylamide.

[0251] CMC: carboxymethylcellulose.

[0252] GMA: glycidyl methacrylate.

[0253] I- Synthesis of hybrid polymers according to the invention:

[0254] 1-1- Synthesis of the oligo-initiator

[0255] The controlled radical polymerization reactions are carried out with 30% by mass of active material.

[0256] Firstly, 2.5g of a chain transfer agent according to formula (IV), 51% acrylamide (AM) (9.87g, or 5.03g of AM), glycidyl methacrylate (GMA) (1.51g) and demineralized water (16.5g) are weighed.

[0257] The transfer agent is dissolved under stirring (magnetic bar) in a 50 mL single-necked flask with a portion of the demineralized water.

[0258] Once it is dispersed and dissolved homogeneously, acrylamide is added. Glycidyl methacrylate (GMA) is then added to the reaction medium, which is accompanied by the formation of suspended droplets.

[0259] An initiator (96.05 mg) is then weighed and added to the reaction medium with the rest of the distilled water.

[0260] The flask is covered with a septum and bubbling with argon is carried out for 30 min within the reaction medium. The flask is then placed under stirring in a oil bath preheated to 60 °C. The flask is kept at 60 °C for 3 h, after which the mixture is allowed to cool to room temperature. The mixture is then poured dropwise into cold acetone to precipitate the polymer, which is then isolated by filtration, before being redissolved in demineralized water, then frozen in order to recover the P(AM-co-GMA) obtained by lyophilization.

[0261] The mass yield is approximately 85%.

[0262] Other syntheses are carried out according to the same protocol by varying the proportions of AM, GMA, transfer agent, and initiator. Table 1 below summarizes this information for oligo-initiators (OA) 1 to 4.

[0263] [Tables 1] OA Formulation (AM / GMA / transfer agent / initiator) Product obtained 1 13 / 0 / 1 / 0.1 PAM 2 10 / 3 / 1 / 0.1 P2(AM-co-GMA) 3 15 / 3 / 1 / 0.1 P3(AM-co-GMA) 4 20 / 3 / 1 / 0.1 P4(AM-co-GMA)

[0264] Table 1: Monomer composition of oligo-initiators 1 to 4 synthesized according to the formulations used.

[0265] 1-2- Functionalization of biopolymer B2

[0266] Biopolymer B1 is a carboxymethylcellulose (CMC). The oligoinitiator used is oligoinitiator 4 previously prepared.

[0267] The CMC is solubilized in a 50 mL round-bottomed flask in distilled water with a CMC concentration of 25 gL-1, at room temperature.

[0268] 175 mg of P4(AM-co-GMA) are introduced into the CMC solution. The reaction is left stirring for 24 h at 50°C. After cooling the reaction medium to room temperature.

[0269] A portion of the reaction medium is transferred into dialysis membranes (Spectra-Por®) with a porosity of 50 kDa. The compound obtained is frozen and then lyophilized. The mass yield of CMC is 73%. Table 2 below summarizes the information relating to the B2 polymers obtained.

[0270] [Tables2] Exp P(AM-co-GMA) CCMC (g / L) Mass ratio CMC / P(AM-co-GMA) introduced (weighed masses) Pla CMC-g-(AM-co-GMA) 25 30 / 70 2b P2CMC-gP(AM-co-GMA) 25 30 / 70 3b P3CMC-gP(AM-co-GMA) 25 42 / 58 4b P4CMC-gP(AM-co-GMA) 25 46 / 54 5b P5CMC-gP(AM-co-GMA) 25 63 / 37 6b P6CMC-gP(AM-co-GMA) 50 77 / 33

[0271] a Non-dialyzed sample (purification by precipitation).

[0272] b Dialyzed sample (dialysis membrane porosity of 50 kDa)

[0273] Table 2 CMC-gP(AM-co-GMA) obtained by varying the CMC / P(AM-co-GMA) mass ratio

[0274] 1-3- Extension of synthetic polymer chains

[0275] In a reactor, are added: 13.19g of sodium acrylate and 46.01g of 51% AM. Argon bubbling is carried out within the reactor for 30 min. 202.11 mg of azo initiator, VA044, are then added to the reaction medium, which is then placed at 40 °C for 4 h. 1.39 g of sodium bisulfite (40% by mass in water) is then added for the so-called 'burn out' step which lasts 1 h at 40 °C.

[0276] The PH hybrid polymer is then obtained. A fraction is taken to analyze the sample by NMR ([Fig.2]).

[0277] II- Counter-example: Synthesis of hybrid polymers according to the “grafting through” strategy:

[0278] In a double-jacketed reactor containing 560 g of water, 20 g of CMC are dissolved overnight at room temperature with stirring. The pH of the reaction medium is adjusted to pH = 8 using a 50% NaOH solution. 2.2 g of GMA are added to the reactor.

[0279] The reactor is then heated to 50°C using a thermostatically controlled bath and the reaction medium is left under mechanical stirring for 24 hours. 13.19 g of acrylic acid (100%) are placed in an ice bath and neutralized with 10 M sodium hydroxide (approximately 18 mL) until a pH of between 6 and 7 is obtained.

[0280] The sodium acrylate (AANa) obtained is added with 46.01 g of 51% AM within the reactor. Bubbling within the reactor is then carried out with a long cannula for 30 min, after which the cannula is placed just above the medium re action within the reactor. 202.11 mg of initiator, VA044, are then added to the reaction medium, which is then placed at 40 °C for 4 h. Then, 1.39 g of sodium bisulfite (40% by mass in water) are introduced to eliminate the vinyl functions remaining in the reactor for 1 h at 40 °C.

[0281] The counterexample hybrid polymer is thus obtained.

[0282] III- Application example: Solubility test

[0283] The PH polymer according to the invention and the counter-example hybrid polymer are compared.

[0284] The two polymers are solubilized at a concentration of 10 gL-1. Then 250 g of these solutions are filtered using a 50 μm filter. The mass of solution recovered after the filter is then weighed and the percentage recovery is calculated by taking the ratio between the recovered mass and the initial mass. The results are given in Table 3.

[0285] [Tables3] PH (invention) Counterexample Mass before filtration at 50 pm (g) 250 250 Mass after filtration at 50 pm (g) 248.9 170.4 Percentage recovery (%) 99.6 68.2

[0286] Table 3: Table of masses of solution recovered before and after filtration at 50 pm

[0287] In the case of the PH hybrid polymer according to the invention, almost all of the solution passed through the 50 pm filter (recovery percentage > 99.5%), which proves the water-soluble nature of the PH hybrid polymer resulting from the strategy of the invention.

[0288] On the other hand, in the case of the counter-example polymer the quantity of solution recovered is much lower than the initial value, pieces of insoluble gels remained on the filter at 50 pm. The “grafting through” strategy therefore does not make it possible to obtain water-soluble polymers, as is the case with the present invention.

Claims

Claims

1. Oligoinitiator of formula (I) (I) s --S--A--Q--R2 R1 -- Z in which ; Z= O, S or NR3 RI, R2 and R3, identical or different, represent: an optionally substituted alkyl, acyl, aryl, alkene or alkyne group (i), or a carbon cycle (ii), saturated or unsaturated, optionally substituted or aromatic, or a heterocycle (iii), saturated or not, optionally substituted, these groups and cycles (i), (ii) and (iii) being able to be substituted by substituted phenyl groups, substituted aromatic groups or alkoxycarbonyl or aryloxycarbonyl groups (-COOR), carboxy (-COOH), acyloxy (-O2CR), carbamoyl (-C0NR2), cyano (-CN), al-kylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkylcarbonyl, phthalimido, maleimido, succinimido, amidino, guanidimo, hydroxy (-OH), amino (-NR2), halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl, groups having a hydrophilic or ionic character such as alkali salts of carboxylic acids, alkali salts of sulfonic acid, polyalkylene oxide chains (POE, POP), cationic substituents, quaternary ammonium salts, R representing a C2-C20 alkyl or aryl group, R3 can also represent a hydrogen atom; A is a monomeric unit or a linear or structured polymer chain comprising nA identical or different hydrophilic monomers comprising at least one unsaturated ethylenic function, with nA being an integer between 0 and 500, Q is a monomeric unit or a linear or structured polymer chain comprising nQ monomers chosen from those having at least one reactive functional group (frQ) of the epoxide and / or anhydride and / or hydroxyl and / or isocyanate and / or acetal and / or aldehyde and / or carboxylic acid and / or ester and / or vinyl type, with nQ being an integer between 1 and 1000.

2. Oligoinitiator according to claim 1, characterized in that the monomeric unit or the polymer chain A comprises hydrophilic monomers comprising at least one unsaturated ethylenic function chosen from non-ionic and / or cationic and / or anionic and / or zwitterionic monomers.

3. Oligoinitiator according to claim 2, characterized in that the non-ionic monomers are chosen from acrylamide, methacrylamide, N,N-dimethylacrylamide, N,N diethylacrylamide, N methylolacrylamide, N-vinylformamide, N-vinyl acetamide, N-vinylpyridine, N-vinylpyrrolidone, acryloyl morpholine (ACMO), diacetone acrylamide, and; glycidyl methacrylate.

4. Oligoinitiator according to claim 2, characterized in that the anionic monomers are chosen from acrylic acid; methacrylic acid; dimethylacrylic acid; itaconic acid; crotonic acid; maleic acid; fumaric acid; acrylamido undecanoic acid; 3-acrylamido 3-methylbutanoic acid; maleic anhydride; strong acid monomers having for example a sulfonic acid or phosphonic acid function such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-1,3-disulfonic acid, 2-sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), 2-acrylamido-2-methylpropane disulfonic acid;water-soluble salts of these monomers such as their alkali metal salts (as distinct from the crystalline form of the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid), alkaline earth metal salts, or ammonium salts; and mixtures thereof.;

5. Oligoinitiator according to claim 2, characterized in that the cationic monomers are chosen from quaternized dimethylaminoethyl acrylate (ADAME), quaternized dimethylaminoethyl methacrylate (MADAME), dimethyldiallylammonium chloride (DADMAC), acrylamido propyltrimethyl ammonium chloride (APTAC), and methacrylamido propyltrimethyl ammonium chloride (MAPTAC).

6. Oligoinitiator according to one of the preceding claims, characterized in that the monomer(s) of the monomeric unit or of the

7.

8. polymer chain Q are chosen from glycidyl methacrylate, methacrylic anhydride, maleic anhydride, itaconic anhydride, hydroxy(alkyl)acrylate, glycidyl acrylate, allyl glycedyl ether, allyl(meth)acrylate. Oligoinitiator according to one of the preceding claims, characterized in that the oligoinitiator has a weight-average molecular weight of between 350 and 1,500,000 Da. Oligoinitiator according to one of the preceding claims, characterized in that the oligoinitiator is of formula (II) (II)

9.

10. in which nA acrylamide unit is between 1 and 300, and nQ glycidyl methacrylate unit is between 1 and 500. Use of the oligo-initiator according to one of claims 1 to 8 for producing a water-soluble polymer. Water-soluble hybrid polymer PH obtained by using the oligo-initiator according to one of claims 1 to 8 and, according to a method comprising at least the following successive steps: (1) Functionalization of a biopolymer B1 by reaction of at least one of its reactive functional groups (frB) with at least one reactive functional group (frQ) of said oligo-initiator, to obtain a functionalized biopolymer B2, (2) Polymerization of hydrophilic monomers comprising at least one ethylenic unsaturation on at least one oligo-initiator of the functionalized biopolymer B2 to form at least one side chain L, and thus obtain the hybrid polymer PH, characterized in that the oligo-initiator is of formula (I) (I) s --s--A--Q--a2 R' — Z in which ; Z= O, S or NR3 R1, R2 and R3, identical or different, represent: an optionally substituted alkyl, acyl, aryl, alkene or alkyne group (i), or a carbon cycle (ii), saturated or unsaturated, optionally substituted or aromatic, or a heterocycle (iii), saturated or not, optionally substituted, these groups and cycles (i), (ii) and (iii) being able to be substituted by substituted phenyl groups, substituted aromatic groups or alkoxycarbonyl or aryloxycarbonyl groups (-COOR), carboxy (-COOH), acyloxy (-O2CR), carbamoyl (-C0NR2), cyano (-CN), al-kylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkylcarbonyl, phthalimido, maleimido, succinimido, amidino, guanidimo, hydroxy (-OH), amino (-NR2), halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl, groups having a hydrophilic or ionic character such as alkali salts of carboxylic acids, alkali salts of sulfonic acid, polyalkylene oxide chains (POE, POP), cationic substituents, quaternary ammonium salts, R representing a C2-C20 alkyl or aryl group, R3 can also represent a hydrogen atom; A is a monomeric unit or a linear or structured polymer chain comprising nA identical or different hydrophilic monomers comprising at least one unsaturated ethylenic function, with nA being an integer between 0 and 500, Q is a monomeric unit or a linear or structured polymer chain comprising nQ monomers chosen from those having at least one reactive functional group (frQ) of epoxide and / or anhydride and / or hydroxyl and / or isocyanate and / or acetal and / or aldehyde and / or carboxylic acid and / or ester and / or vinyl type, with nQ being an integer between 1 and 1000, characterized in that the biopolymer B1 is native or modified, and comprises at least one reactive functional group (frB) of hydroxy and / or carboxy and / or anhydride and / or amine and / or amide and / or vinyl type, and / or phosphate and / or sulfonate and / or ester and / or aldehyde and / or ketone and / or silane, and / or isocyanate and / or nitrile and / or acyl halide.

11. Water-soluble hybrid polymer PH, according to claim 10, characterized in that the oligo-initiator is of formula (I) with: Z=O, RI and R2 represent an optionally substituted alkyl, acyl, aryl, alkene or alkyne group, A is a monomeric unit or a linear polymer chain comprising nA 1 to 300 monomeric units; Q is a monomeric unit or a linear polymer chain comprising nQ 1 to 500 monomeric units.

12. Water-soluble hybrid polymer PH according to one of claims 10 or 11, characterized in that the monomer(s) of the monomeric unit or of the polymer chain A are chosen from; acrylamide, acrylic acid, an oligomer of acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS) and / or one of its salts, N-vinylformamide (NVF), N-vinylpyrrolidone (NVP), dimethyldiallylammonium chloride (DADMAC), quaternized dimethylaminoethyl acrylate (ADAME), quaternized dimethylaminoethyl methacrylate (MADAME).

13. Water-soluble hybrid polymer PH according to one of claims 10 to 12, characterized in that the percentage of reactive functions (frB) substituted by the oligo-initiator in the biopolymer B2 is between 0.1 and 90%.

14. PH hybrid polymer according to one of claims 10 to 13, characterized in that the biopolymer Bi comprises at least one reactive functional group (frB) chosen from hydroxy, carboxylate or anhydride functions.

15. PH hybrid polymer according to one of claims 10 to 14, characterized in that the biopolymer Bi is a polysaccharide.

16. PH hybrid polymer according to claim 15, characterized in that the polysaccharide is chosen from starch or its derivatives, carboxymethyl starch; cellulose or its derivatives, carboxymethylcellulose, hemicellulose; polysaccharides extracted from algae, agarose, carrageenans, alginates; pectins; inulin; guar gums; konjac gum; dextran; pullulan; gellan; curdlan.

17. Water-soluble hybrid polymer PH according to one of claims 10 to 16, characterized in that the side chain(s) L have a weight-average molecular weight of between 5000 and 1,000,000 Da.

18. Use of the water-soluble hybrid polymer PH according to one of claims 10 to 17 in a field chosen from hydrocarbon recovery; in the drilling and cementing of wells; in the sti- mulation of hydrocarbon wells; in water treatment; in the treatment of fermentation musts; in the treatment of sludge; in the manufacture of paper or cardboard; in construction; in the treatment of wood; in the treatment of hydraulic composition; in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; in the manufacture of textiles; in the manufacture of battery components; in geothermal energy; or in agriculture.

19. Use of the water-soluble hybrid polymer PH according to one of claims 10 to 17 as a flocculant, coagulant, dispersant, binding agent, fixing agent, viscosity reducing agent, thickening agent, absorbent agent, friction reducing agent, dewatering agent, drainage agent, charge retention agent, dehydrating agent, conditioning agent, stabilizing agent, fixing agent, film-forming agent, sizing agent or clay inhibitor.

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