POLYMERIZATION PROCESS FOR OBTAINING POLYMERS WITH IMPROVED DEGRADABILITY

Abstract

The present invention relates to a new polymerization process for a polymer with improved degradability, said polymer and its use.

Description

Title of the invention: POLYMERIZATION PROCESS FOR OBTAINING POLYMERS WITH IMPROVED DEGRADABILITY TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a process for polymerizing a polymer with improved degradability, said polymer and its use. PRIOR STATE OF THE ART

[0002] Polyacrylamides (PAM) are water-soluble synthetic polymers having a wide range of applications such as wastewater treatment, paper manufacturing, cosmetics, textiles, agriculture, construction, oil recovery and mining.

[0003] Due to their polymeric nature, i.e. their high molecular weight, polyacrylamides are considered inert and non-toxic, both for the environment and for humans, with a low risk of bioaccumulation in plants. However, the regulation of chemical products and the monitoring of their possible evolution in nature apply to these compounds. Thus, the specifications to be respected are increasingly restrictive for manufacturers and vary depending on the applications and the countries. The degradation of these polymers in the environment and their metabolization by microorganisms therefore remains a major subject of research in order to respond to the ecological challenges of our time.

[0004] There are several ways to degrade PAMs, divided into two processes: abiotic degradation and biotic degradation also called biodegradation.

[0005] Abiotic transformations include, among other things, mechanical, chemical and photochemical degradations that can be forced or occur automatically in nature. They allow the molecular weight of the polymer to be reduced by breaking the chains into smaller and smaller fragments until oligomers are obtained (very small polymers with a number of repeating units not exceeding a few dozen).

[0006] Biotic transformations include biological processes, i.e. the digestion of oligomers by microorganisms such as fungi, bacteria or enzymes. At the end of this biodegradation, the polymer is completely degraded and metabolized.

[0007] The prior degradation of polymers is essential to initiate biodegradation. It is indeed necessary that the polymer fragment or oligomer can cross the cellular barrier in order to be metabolized. This is applicable to all polymers and it has been shown that rapid metabolization of PAM, as is the case in standardized tests, is only possible for a degree of polymerization lower than 7 (heptamer).

[0008] Abiotic transformations can be accelerated by manufacturers, but the various existing treatments (mechanical or chemical) involve additional steps leading to logistics that run counter to ecological issues, including, in particular, higher equipment, product use, energy consumption and costs.

[0009] Other solutions are known to improve the degradation rate, in particular the incorporation into the polymer chain of so-called "weak points" corresponding to the inclusion of particular chemical functions leading to the fragmentation of the main hydrocarbon chain of the polymer. This fragmentation reaction can be carried out quickly under relatively mild conditions close to those encountered in nature.

[0010] The incorporation of the weak point can be done by the addition of an additional monomer inducing a hydrolyzable function, for example a cyclic ketene acetal. The polymerization of a cyclic ketene acetal is done by ring opening polymerization ("radical ring opening polymerization" in English (rROP)), thus making it possible to integrate an ester function into the structure of the polymer, a function which is easily hydrolyzable.

[0011] The main problem for these polymers remains the way in which the points of weakness are distributed along the chain. This aspect is fundamental since it will govern the molar mass and the mass dispersity of the fragments obtained after degradation. A significant dispersity will induce heterogeneous fragments, of all sizes, the largest of which will not allow them to cross the cellular barrier of microorganisms to be biodegraded.

[0012] There is therefore a need to control the distribution of points of fragility (points of weakness) on the main chain of the polymer, which results in the case of monomers inducing hydrolyzable functions, by a homogeneous incorporation of these monomers during polymerization.

[0013] The Applicant has discovered a new polymerization process making it possible to obtain PAM derivatives having improved degradation while retaining good application properties.

[0014] The polymerization process, the resulting polymers and their use are part of a principle of respect for the environment and limitation of pollution. The better degradability of the polymer reduces the environmental impact of the applications using it. Statement of the invention

[0015] The present invention relates to a process for preparing a polymer by radical polymerization of specific monomers, in particular a cyclic monomer. The different polymers are added during casting.

[0016] More precisely, it is a process for preparing a polymer by radical polymerization in casting of at least two monomers: - at least one monomer A chosen from: (meth)acrylamide, (meth)acrylamide derivatives, (meth)acrylic acid, (meth)acrylic acid derivatives and mixtures thereof; and - at least one cyclic monomer B chosen from: cyclic ketene acetals, thionolactones and their mixtures.

[0017] Due to the combination of the polymerization technique (introduction of monomers during casting) and the nature of the monomers (specific cyclic monomer), this process makes it possible to improve the degradability properties of the polymer.

[0018] The present invention also relates to a polymer obtained according to this process.

[0019] The present invention also relates to the use of this polymer in the recovery of hydrocarbons (oil and / or gas); in the drilling or cementing of wells; in the stimulation of hydrocarbon wells (oil and / or gas), for example hydraulic fracturing, conformation, diversion; in the treatment of water in open, closed or semi-closed circuits; in the treatment of fermentation musts; in the treatment of sludge; in construction; in the manufacture of paper or cardboard; in the field of batteries; in the treatment of wood; in the treatment of hydraulic composition (concrete, cement, mortar and aggregates); in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; in the manufacture of textiles; in geothermal energy; in the manufacture of hygienic diapers; or in agriculture.

[0020] Finally, the present invention also relates to the use of this polymer as a flocculant, coagulant, 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, superplasticizing agent, clay inhibitor or dispersant. DESCRIPTION OF THE INVENTION

[0021] In the description of the invention, the term "polymer" refers to the polymer resulting from the process according to the invention. This polymer has improved degradability compared to polymers obtained from conventional processes.

[0022] This polymer is prepared from at least two different monomers. In addition to the monomers A and B, it may also comprise at least one hydrophilic monomer (distinct from monomers A and B) chosen from hydrophilic anionic monomers, hydrophilic cationic monomers, hydrophilic non-ionic monomers, hydrophilic zwitterionic monomers and mixtures thereof.

[0023] By “hydrophilic monomer” is meant a monomer which has an octanol / water partition coefficient, Kow, less than or equal to 1, in which the partition coefficient Kow is determined at 25°C in an octanol / water mixture having a volume ratio of 1 / 1, at a pH between 6 and 8.

[0024] By "hydrophobic monomer" is meant a monomer which has an octanol / water partition coefficient, Kow, greater than 1, in which the partition coefficient Kow is determined at 25°C in an octanol / water mixture having a volume ratio of 1 / 1, at a pH between 6 and 8.

[0025] The octanol / water partition coefficient, Kow, represents the ratio of concentrations (g / L) of a monomer between the octanol phase and the aqueous phase. It is defined as follows:

[0026] [Math.l] [monomer 1 _ 2___________J wtMid A-ow r - i monomer LJ water

[0027] By "water-soluble" is meant a compound (for example a polymer or a monomer) which gives an aqueous solution without insoluble particles when dissolved under stirring at 25°C and with a concentration of 10 g.l1 in deionized water.

[0028] By “X and / or Y” we mean “X”, or “Y”, or “X and Y”.

[0029] 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.

[0030] By "improved degradability" is meant that the dispersity of the polymer fragments obtained after hydrolysis of the polymer is less than 5.0, preferably less than 4, more preferably less than 3, and even more preferably less than 2.5.

[0031] The polymer according to the invention comprises at least one monomer A and at least one cyclic monomer B. Polymerization process

[0032] The polymerization according to the invention is a radical polymerization. For monomer B, it is more particularly a radical polymerization by cycle opening.

[0033] 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.

[0034] Ring-opening radical polymerization (rROP), implemented for monomer B, 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.

[0035] By radical polymerization we include free radical polymerization using UV, azo, redox or thermal initiators.

[0036] The polymerization reaction is advantageously initiated by introducing a free radical initiator. The polymerization initiator(s) used are advantageously chosen from compounds which dissociate into radicals under the polymerization conditions. In certain cases, it is advantageous to use mixtures of various polymerization initiators, for example mixtures of redox catalysts and azo compounds.

[0037] According to the invention, the quantity of initiator is advantageously between 1 and 100,000 ppm relative to the total weight of monomer, preferably between 50 and 50,000 ppm, more preferably between 100 and 30,000 ppm, and even more preferably between 500 and 20,000 ppm.

[0038] Generally speaking, the polymer according to the invention does not require the development of a particular polymerization process. On the other hand, it requires the introduction of the monomers in casting. The polymer can be obtained according to all the polymerization techniques well known to those skilled in the art. It may in particular be polymerization in solution in water or in brine (water-in-water polymerization), emulsion polymerization (aqueous or inverse). Preferably, it is solution polymerization.

[0039] In a preferred embodiment, the radical polymerization is a controlled radical polymerization. Mention may be made, without limitation, of techniques such as iodine transfer polymerization (ITP), nitroxide-mediated polymerization (NMP), atom transfer polymerization (ATRP), reversible addition-fragmentation chain transfer polymerization (RAFT), which includes the MADIX technology (MAcromolecular Design by Interchange of Xanthates), various variations of polymerizations with organometallic compounds (Organometallic OrganoHeteroatom-mediated Radical Polymerization (OHRP)

[0040] The activation-deactivation process linked to controlled radical polymerization allows the chains to grow at the same speed until the total consumption of the monomer, making it possible to control the molecular weights of the polymers and to obtain narrow molecular weight distributions. This will also make it possible to minimize the heterogeneity of the composition. The reversible deactivation of the growing chains is at the origin of the minimization of irreversible termination reactions. The vast majority of the polymer chains remain in dormant form and are therefore reactivatable. It is then possible to functionalize the chain ends in order to initiate other polymerization modes or to make chain extensions. This makes it possible to control the molecular weight of the compositions and the architecture of the polymer.

[0041] Controlled radical polymerization therefore has the following distinctive aspects: 1- The number of polymer chains is fixed throughout the duration of the reaction, 2- The polymer chains all grow at the same speed, which results in: * A linear increase in molecular weights, * A tight distribution of molecular weights, 3- The average molecular weight is controlled by the monomer / control agent molar ratio.

[0042] The controlled nature is all the more marked as the rate of reactivation of the radical chains is clearly higher than the rate of growth of the chains (propagation). However, in certain cases, the rate of reactivation of the radical chains is higher than or equal to the rate of propagation. In these cases, conditions 1 and 2 are not observed and, consequently, control of the molecular weights is not possible.

[0043] In a preferred embodiment, the polymer is obtained by reversible addition-fragmentation chain transfer polymerization.

[0044] Reversible addition-fragmentation chain transfer polymerization requires the presence of at least one control agent advantageously of formula (I):

[0045] [Chem.l]

[0046] in which - Z= O, S or N; - Ri and R2, identical or different, represent: * an optionally substituted alkyl, acyl, alkenyl or alkynyl group (i), or * a carbon cycle (ii), saturated or not, possibly substituted or aromatic, or * a heterocycle (iii), saturated or unsaturated, optionally substituted or aromatic, these groups and cycles (i), (ii) and (iii) being able to be substituted by substituted aromatic groups or by alkoxycarbonyl or aryloxycarbonyl (-COOR), carboxy (-COOH), acyloxy (-O2CR), carbamoyl (-CON(R)2), cyano (-CN), alkylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkylcarbonyl, phthalimido, maleimido, succinimido, amidino, guanidimo, hydroxy (-OH), amino (-N(R)2), 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 CrC2o alkyl or aryl group; - Q is a linear or structured polymer chain comprising n identical or different monomers comprising at least one ethylenic function; - n is an integer between 0 and 500, advantageously between 1 and 500, more advantageously between 1 and 100.

[0047] The monomer(s) used to form Q are advantageously chosen from the same hydrophilic monomers as those described to form the polymer.

[0048] In the NR2 functions, the two R groups can be identical or different from each other.

[0049] In a preferred embodiment, the control agent is of formula (I) in which Z = O.

[0050] In another preferred embodiment, the control agent is of formula (I) in which: -Z = O, - Q is a linear or structured polymer chain obtained from 1 to 100 monomers comprising at least one non-ionic monomer and / or at least one

[0051]

[0052]

[0053] anionic monomer and / or at least one cationic monomer. In another preferred embodiment, the control agent is of formula (I) in which: -Z = O, - Q is a linear or structured polymer chain obtained from 1 to 100 monomers comprising at least one non-ionic monomer and / or at least one anionic monomer. In another preferred embodiment, the control agent is of formula (II): [Chem. 2]

[0054]

[0055]

[0056]

[0057] (II) in which n is an integer between 0 and 100, preferably between 1 and 50. In another preferred embodiment, the control agent is of formula (I) in which Z = S. In another preferred embodiment, the control agent is of formula (III): [Chem. 3]

[0058] (III) in which - The R3 groups are identical or different, independently represent an H or a CH3 or a cation, advantageously chosen from cations of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium (for example the ion ammonium or tertiary ammonium), preferably sodium.

[0059] In another preferred embodiment, the control agent is of formula (IV):

[0060] [Chem.4] (IV)

[0061] In which - The R3 groups are identical or different, independently represent an H or a CH3 or a cation, the cation being advantageously chosen from cations of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium (for example the ammonium ion or a tertiary ammonium), preferably sodium; and n and n' are whole numbers independent of each other, between 0 and 100, preferably between 1 and 50.

[0062] In another preferred embodiment, the control agent is of formula (V):

[0063] [Chem.5] (V)

[0064] in which - The R3 groups are identical or different, independently represent an H or a CH3 or a cation, advantageously chosen from cations of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium (for example the ammonium ion or a tertiary ammonium), preferably sodium.

[0065] In another preferred embodiment, the control agent is of formula (VI):

[0066] [Chem.6] (Vi)

[0067] in which - The R3 groups are identical or different, independently represent an H or a CH3 or a cation, the cation being advantageously chosen from cations of alkali metals (Li, Na, K...), alkaline earth metals (Ca, Mg...) or ammonium (for example the ammonium ion or a tertiary ammonium), preferably sodium; and n is an equal integer, between 0 and 100, preferably between 1 and 50.

[0068] According to the invention, the polymer may have a linear, branched (ramified), star (star-shaped), comb (comb-shaped), dendritic or block structure. These structures may be obtained by selecting the choice of initiator, transfer agent, polymerization technique such as controlled radical polymerization known as RAFT (Reversible-Addition Fragmentation Chain Transfer), NMP (Nitroxide Mediated Polymerization) or ATRP (Atom Transfer Radical Polymerization), incorporation of structural monomers, concentration...

[0069] The radical polymerization of the monomers (in particular by ring opening for monomer B) is advantageously carried out at a temperature between 10 and 90°C, preferably between 25 and 80°C, more preferably between 40 and 60°C.

[0070] The radical polymerization of the monomers (in particular by ring opening for monomer B) advantageously lasts between 60 minutes and 1440 minutes, preferably between 120 minutes and 720 minutes, more preferably between 180 minutes and 360 minutes.

[0071] Advantageously, the radical polymerization is carried out in an organic solvent. The organic solvent can be used in a mixture with water, or salt water (for example with ammonium sulfate). Examples of organic solvents that may be mentioned include: hydrocarbons such as toluene, xylene, hexane and heptane; chlorinated solvents such as methylene chloride, chloroform and dichloromethane; romethane; ethers such as diethyl ether, tetrahydrofuran, and dibutyl ether; ketones such as acetone and 2-butanone; esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; and polar aprotic solvents such as dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF). The solvents can be used alone or in mixtures. Preferably, the polymerization takes place in dimethyl sulfoxide.

[0072] In certain cases, it is possible to use protic polar solvents such as tert-butanol. Thus the invention is not limited to organic solvents; a person skilled in the art is able to determine which protic polar solvents are likely to work depending on the cyclic monomer B used.

[0073] The integration of the cyclic B monomers into the polymer chains is controlled by casting polymerization. Casting

[0074] The polymerization process is carried out by casting: the monomers are added by casting, i.e. progressively (for example drop by drop) throughout the polymerization (i.e. continuously).

[0075] The process according to the invention can be carried out in a polymerization tank (or a reactor) according to the following steps: - optionally, introduction of an initiator, advantageously in the presence of a solvent, - casting of monomers A and B, monomers A and B being advantageously in solution in a solvent, - polymerization of monomers.

[0076] The casting of monomers A and B may be a casting of monomer A and a separate casting of monomer B. In this case, the castings may be carried out simultaneously, staggered, one after the other or alternately. It is also possible to interrupt a casting of one monomer to carry out a casting of another monomer. The following sequences may therefore be envisaged: - simultaneously: for example 100% A and 100% B, - staggered: for example 100% A continuously and, after the start of the introduction of A, 100% B continuously, - one after the other: for example 100% A then 100% B, - alternatively: for example x% A then y% B, then (100-x)% A, - alternatively: for example x% A then y% B, then z% A, then (100-y)% B, then (100-xz)% A.

[0077] The same sequences can be envisaged by inverting the monomers A and B.

[0078] In a particular mode, the castings have a composition gradient in order to obtain polymers with a gradient structure.

[0079] Gradient structure polymers are polymers composed of at least two monomers in which the change in composition of the monomers is gradual, unlike block polymers, which undergo an abrupt change in composition, and random polymers, which do not have a continuous change in composition.

[0080] Depending on the sequence chosen, the polymerization of the monomers can begin before the introduction of monomer A or monomer B. Advantageously, the polymerization of the monomers begins as soon as one of the monomers A or B is introduced.

[0081] The monomer(s) are advantageously cast in solution in a solvent.

[0082] Where appropriate, the initiator is advantageously added (for example in a polymerization tank) with a solvent before the start of the monomer flow(s).

[0083] Polymerization advantageously begins at the moment when the first type of monomer, a solvent and an initiator are in contact.

[0084] The duration of the casting (regardless of the monomer) is advantageously between 60 minutes and 1440 minutes, preferably between 60 minutes and 720 minutes, more preferably between 60 minutes and 360 minutes. This is the time necessary to introduce all of the monomer(s) concerned, without taking into account any interruptions in casting.

[0085] Monomers A and B are added in a pour, advantageously at a constant flow rate. The flow rate of the pour of monomer A may be identical or different from that of the pour of monomer A.

[0086] The monomer(s) A and the monomer(s) B may be added in liquid form or in particle form, preferably they are added in liquid form in a solvent.

[0087] By "particle form" is meant in powder form, in ball form or a mixture, of regular size (or not) and spherical (or not).

[0088] The monomer(s) A and the monomer(s) B may be added separately or as a mixture. Preferably, they are added separately, in separate pours.

[0089] In other words, in a preferred embodiment, the polymerization process comprises at least two castings, a first casting comprising the monomer(s) A and a second casting comprising the monomer(s) B.

[0090] Advantageously, the casting time of the monomer(s) A is different from the casting time of the monomer(s) B, a gradient polymer is then obtained.

[0091] The duration of the casting of the monomer(s) A is advantageously between 30 minutes and 720 minutes, preferably between 30 minutes and 360 minutes, more preferably between 60 minutes and 180 minutes.

[0092] The duration of the casting of the monomer(s) B is advantageously between 60 minutes and 720 minutes, preferably between 60 minutes and 480 minutes, more preferably between 60 minutes and 360 minutes.

[0093] The molar ratio between the monomer(s) A and the monomer(s) B is advantageously between 50:50 and 98:2, preferably between 70:20 and 95:5.

[0094] In a particular embodiment according to the invention, the monomer(s) B are added to the polymerization tank and the monomer(s) A are added during casting.

[0095] When the polymer comprises several monomers A, they can be added together or separately, preferably they are added together.

[0096] In a preferred embodiment according to the invention, the monomer B is a mixture of two different monomers: Bi and B2. In this case, Bi and B2 can be introduced separately from each other or simultaneously. They can be introduced in a single pour or in two separate pours.

[0097] The molar ratio between the monomer(s) A, the monomer Bi and the monomer B2 is advantageously between 50:30:20 and 93:5:2, preferably between 70:20:10 and 90:5:5.

[0098] The monomers A, Bi and B2 are advantageously added separately, for example in 3 separate pours.

[0099] Advantageously, the monomer Bi is a cyclic ketene acetal, and the monomer B2 is a thionolactone.

[0100] When the polymer comprises several monomers B, they can be added together or separately, preferably they are added separately.

[0101] In other words, in another preferred embodiment according to the invention, the polymerization process comprises at least three castings, a first casting comprising the monomer(s) A, a second casting comprising a monomer Bi and a third casting comprising a monomer B2 different from Bb.

[0102] Advantageously, the casting time is different from one monomer to another. The casting time of monomer A is advantageously different from the casting time of monomer Bi which is also different from the casting time of monomer B2.

[0103] In this embodiment (A, Bi and B2), the duration of the casting of the monomer(s) A is advantageously between 30 minutes and 720 minutes, preferably between 30 minutes and 360 minutes, more preferably between 60 minutes and 180 minutes.

[0104] The duration of the casting of the monomer(s) Bi is advantageously between 60 minutes and 720 minutes, preferably between 60 minutes and 480 minutes, more preferably between 60 minutes and 360 minutes.

[0105] The duration of the casting of the monomer(s) B2 is advantageously between 60 minutes and 720 minutes, preferably between 60 minutes and 480 minutes, more preferably between 60 minutes and 360 minutes.

[0106] The castings of the monomers A, Bi and B2 can be carried out simultaneously, one after the other or in a staggered manner (i.e. at least one of the castings begins after the start of at least one other casting of monomers and before the end of said casting).

[0107] Advantageously, the casting of the monomer(s) B2 begins at the end of the casting of the monomer(s) Bh.

[0108] In a particular embodiment according to the invention, the monomer(s) Bi and / or B2 are added to the polymerization tank and the monomer(s) A are added during casting.

[0109] In a particular embodiment according to the invention, the monomer(s) Bi are added to the polymerization tank and the monomer(s) A and B2 are then added during casting.

[0110] The castings of monomers A and B2 may be carried out simultaneously, one after the other or in a staggered manner (i.e. at least one of the castings begins after the start of at least one other casting of monomers and before the end of said casting). The casting of monomer B2 advantageously begins at the end of the casting of monomer A.

[0111] The present invention also relates to the polymer obtained according to the process of the invention. Polymer

[0112] The polymer according to the invention is a synthetic polymer comprising (advantageously consisting of): - at least one monomer A; and - at least one cyclic monomer B.

[0113] The polymer according to the invention may be water-soluble, water-swelling or superabsorbent. Preferably, it is water-soluble.

[0114] The monomer A used in the context of the invention may be non-ionic, anionic, or cationic. It may be used alone, in a mixture of two or more.

[0115] Depending on the applications, the nature of the PAMs changes as well as their monomeric composition and the percentages of the monomers constituting them. The invention aims to be able to replace any PAM with an equivalent PAM with improved degradability having equivalent performances. Thus, the invention is not limited to a monomeric percentage. Monomer A

[0116] Monomer A is chosen from: (meth)acrylamide, (meth)acrylamide derivatives, (meth)acrylic acid, (meth)acrylic acid derivatives and mixtures thereof. These monomers may be non-ionic hydrophilic monomers, hydrophilic anionic, cationic hydrophilic, or zwitterionic hydrophilic.

[0117] Non-ionic hydrophilic monomer A

[0118] Advantageously, the non-ionic hydrophilic monomer(s) that can 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), glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, hydroxyalkyl (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. Preferably, the non-ionic hydrophilic monomer is acrylamide.

[0119] Anionic hydrophilic monomer A

[0120] Advantageously, the anionic hydrophilic 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; C1-C22 itaconic acid hemi-esters; itaconic anhydride; itaconamide; crotonic acid; acryloyl chloride; 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; the water-soluble salts of these monomers such as their alkali metal, alkaline earth metal or ammonium salts; and mixtures thereof. Preferably, the anionic hydrophilic monomer(s) is acrylic acid and / or its salts.;

[0121] 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.

[0122] 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(=0)-0 X+, X+ corresponding to an alkali or ammonium cation. The salification of the acid functions of the polymer can be partial or total.

[0123] 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.

[0124] Salification can be done before, during or after polymerization.

[0125] Cationic hydrophilic monomer A

[0126] Advantageously, the cationic hydrophilic 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, tertiary ammonium or quaternary ammonium function.Mention may be made, in particular and without limitation, 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), vinylamine obtained by the hydrolysis (basic or acidic) of an amide group -N(R2)-CO-R1 with R1 and R2 being, independently, a hydrogen atom or an alkylated chain of 1 to 6 carbons, vinylamine obtained by Hofmann degradation and mixtures thereof.Advantageously, the alkyl groups are C1-C3.

[0127] A person skilled in the art will know how to prepare the quaternized monomers, for example using a quaternizing agent of type RX, R being an alkyl group and X being a halogen or a sulfate.

[0128] By “quaternizing agent” we mean a molecule capable of alkylating a tertiary amine.

[0129] 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.

[0130] Furthermore, the present invention also covers DADMAC, APTAC and MAPTAC type monomers whose counterion is a sulfate, a fluoride, a bromide or an iodide instead of chloride.

[0131] Zwitterionic hydrophilic monomer A

[0132] Advantageously, the hydrophilic zwitterionic monomer(s) may be a derivative of a vinyl-type unit (advantageously acrylamide, acrylic, allyl or maleic), this monomer having an amine, tertiary ammonium 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 without limitation, of derivatives of dimethylaminoethyl acrylate, such as 2-((2-(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, 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, derivatives of dimethylaminopropylacrylamide 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, derivatives of dimethylaminopropylmethylacrylamide 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.

[0133] In a preferred embodiment according to the invention, the polymer does not comprise a hydrophobic monomer.

[0134] Branching Agent and Chain Transfer Agent

[0135] The polymer according to the invention may comprise a branching agent.

[0136] The branching agent is advantageously chosen from: - structural agents, which may be chosen from the group comprising monomers with polyethylene unsaturation (having at least two unsaturated functions), such as for example vinyl functions, in particular allylic or acrylics, and examples include methylene bis acrylamide (MBA), triallyamine, or tetraallylammonium chloride or 1,2 dihydroxyethylene bis-(N-acrylamide), - monomers having at least two epoxy functions, - monomers having at least one unsaturated function and one epoxy function, - macroinitiators such as polyperoxides, polyazos and polytransfer agents such as polymercaptant polymers, and polyols, - functionalized polysaccharides, - water-soluble metal complexes composed of: * a metal with a valence greater than 3 such as, by way of example and without limitation, aluminum, boron, zirconium or titanium, and * of a ligand carrying a hydroxyl function.

[0137] In a preferred embodiment, the branching agent is chosen from branching agents having a hydrolyzable function, in particular ester. In other words, the branching agent is advantageously a labile branching agent.

[0138] A labile branching agent is a branching agent that can be degraded in the presence of certain heat conditions and / or over time, after being incorporated into the polymer structure. Polymer storage conditions, temperature, and the presence of electrolytes can cause the bonds in the labile branching agent to cleave.

[0139] The labile branching agent is advantageously chosen from diamine diacrylamides and diamine methacrylamides such as piperazine diacrylamide; acrylate esters; methacrylate esters; ethylene glycol diacrylate; polyethylene glycol (PEG) diacrylate; trimethylpropane trimethacrylate; ethoxylated trimethylol triacrylate; ethoxylated pentaerythritol tetracrylate; vinyl esters of di, tri or tetrafunctional acids; allylic esters of di, tri or tetrafunctional acids; and mixtures thereof.The labile branching agent is preferably selected from water-soluble diacrylates such as PEG 200 diacrylate, PEG 400 diacrylate, PEG 600 diacrylate, PEG 1000 diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trethylene glycol diacrylate, tetraethylene glycol diacrylate, and polyfunctional vinyl derivatives of a polyalcohol such as ethoxylated trimethylol (9-20) triacrylate.

[0140] When the polymer is water-soluble and comprises a branching agent, the polymer remains soluble in water. Those skilled in the art will know how to adjust the amount of branching agent, and possibly the amount of transfer agent, in order to achieve this result.

[0141] In a preferred embodiment, the polymer does not comprise a branching agent.

[0142] In a particular embodiment, the polymer may comprise a transfer agent.

[0143] The transfer agent is advantageously chosen from methanol; isopropyl alcohol; sodium hypophosphite; calcium hypophosphite; magnesium hypophosphite; potassium hypophosphite; ammonium hypophosphite; formic acid; sodium formate; calcium formate; magnesium formate; potassium formate; ammonium formate; 2-mercaptoethanol; 3-mercaptopropanol; dithiopropylene glycol; thioglycerol; thioglycolic acid; thiohydracrylic acid; thiolactic acid; thiomalic acid; cysteine; aminoethanethiol; thioglycolates; allyl phosphites; allyl mercaptans, such as n-dodecyl mercaptan; sodium methallysulfonate; calcium methallysulfonate; magnesium methallysulfonate; potassium methallysulfonate; ammonium methallysulfonate;alkyl phosphites such as trialkyl (C12-C15) phosphites, di-oleyl-hydrogen phosphites, dibutyl phosphite; dialkyldithiophosphates such as dioctyl phosphonate; tertiary nonyl mercaptan; 2-ethylhexyl thioglycolate; n-octyl mercaptan; n-dodecyl mercaptan; tert-dodecyl mercaptan; isooctylthioglycolate; 2-Ethylhexyl thioglycolate; 2-Ethylhexyl mercaptoacetate; polythiols; and mixtures thereof. Preferably, these are sodium hypophosphite or sodium formate.

[0144] In a particular embodiment, the polymer does not comprise a transfer agent. Molecular weight

[0145] The polymer may have a molecular weight covering all applications in which PAMs may be used. Thus, the polymer according to the invention may have a molecular weight of between 500 g / mol and 50,000 g / mol, or 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.

[0146] 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: [q] = KM" [q] represents the intrinsic viscosity of the polymer determined by the method of measurement of viscosity in solution. K represents an empirical constant. M represents the molecular weight of the polymer. a represents the Mark-Houwink coefficient. K and a depend on the particular polymer-solvent system. Monomer B

[0147] The cyclic monomer(s) B which can be used in the context of the invention can be chosen from: cyclic ketene acetals, thionolactones and mixtures thereof.

[0148] The cyclic ketene acetal is advantageously chosen from: 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).

[0149] Advantageously, the amount of cyclic ketene acetal in the polymer is between 5 and 30 mol%, relative to the total amount of monomers in the polymer, preferably between 5 and 20 mol%.

[0150] 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.

[0151] Advantageously, the quantity of thionolactones in the polymer is between 2 and 20 mol%, relative to the total quantity of monomer in the polymer, preferably between 5 and 15 mol%.

[0152] In a preferred embodiment according to the invention, the polymer is a polymer of a monomer A and a monomer B: - monomer A being chosen from: (meth)acrylamide, (meth)acrylamide derivatives, (meth)acrylic acid, (meth)acrylic acid derivatives, and mixtures thereof; - monomer B being a mixture of monomer B i and monomer B2, * the monomer Bi being at least one monomer chosen from cyclic ketene acetals; * monomer B2 being at least one monomer chosen from thionolactones. Use

[0153] The present invention also relates to the use of this polymer in the recovery of hydrocarbons (oil and / or gas); in the drilling or cementing of wells; in the stimulation of hydrocarbon wells (oil and / or gas), for example hydraulic fracturing, conformation, diversion; in the treatment of water in open, closed or semi-closed circuit; in the treatment of fermentation musts; in the treatment of sludge; in construction; in the manufacture of paper or cardboard; in the field of batteries; in the treatment of wood; in the treatment of hydraulic composition (concrete, cement, mortar and aggregates); in the mining industry; in the formulation of cosmetic products; in the formulation of detergents; in the manufacture of textiles; in geothermal energy; in the manufacture of hygienic diapers; or in agriculture.

[0154] Finally, the present invention also relates to the use of this polymer as a flocculant, coagulant, 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, superplasticizing agent, clay inhibitor or dispersant.

[0155] The invention and the advantages arising therefrom will become more apparent from the following examples given to illustrate the invention, and not in a limiting manner. EXAMPLES

[0156] List of abbreviations: AM or AMD: Acrylamide DOT: Dibenzo[c,e]oxepine(7H)-5-thione AIBN: Azobisisobutyronitrile DMSO: Dimethyl sulfoxide THF: Tetrahydrofuran D: Dispersal MDO: 2-methylene-1,3-dioxepane P(AM-co-DOT): polymer of acrylamide and dibenzo[c,e]oxepine(7H)-5-thione Accelerated hydrolysis procedure

[0157] In a 5 mL flask equipped with a magnetic stirrer, 5 mg of the desired polymer is dissolved in 1 mL of sodium hydroxide solution (5% by weight in water). The mixture is then stirred for 24 h at room temperature. The solution comprising the polymer is then cooled by adding 1.5 mL of an aqueous HCl solution (1 M). The resulting solution was then dried at 40 °C under vacuum to give a white powder. The degraded polymer was then analyzed by SEC chromatography.

[0158] - Instrument: SEC * Columns: PL PolarGel-M, 300 x 7.5 mm; bead diameter 8 qm; molar mass range 1000-500000 g / mol, preceded by a PL PolarGel-M column, 50 x 7.5 mm; bead diameter 8 qm - Method : * Temperature: 60°C * Mobile phase: DMSO, 100 mM LiBr + 0.36 wt% 2,6-di-tert-butyl-4-methylphenol (BHT) * Flow rate: 0.7 mL / min * Detection: Triple detection system (Viscotek TDA / GPCmax from Malvern) with: - Differential refractive index detector; - Low angle and right angle light scattering detector; - Differential viscometer detector. Example 1 - Thionolactones

[0159] Polymer 1 - Conventional polymerization

[0160] In a 10 mL round-bottomed flask equipped with a mechanical stirrer, a thermometer, a condenser and an argon gas dipstick, 4.2 mmol of AM, 0.42 mmol of DOT, 0.014 mmol of 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid and 0.004 mmol of AIBN are introduced into 2.3 mL of a DMSO / water mixture (86 / 14%v). The medium is bubbled with argon, to remove dissolved oxygen, for 30 min at room temperature. The medium is then heated to 80°C for 22 h with stirring. After cooling to room temperature, the polymer is recovered by precipitation in THF, then centrifuged at 5,000 rpm for 10 min. After removal of the liquid fraction, THF is added and the polymer is suspended in a sonic bath. The P(AM-co-DOT) is then filtered and dried at 40°C under vacuum for 24 h. Polymer 1 is then obtained.

[0161] Polymer 2 - Casting Polymerization

[0162] In a 10 mL round-bottomed flask equipped with a mechanical stirrer, a thermometer, a condenser, and an argon gas dipstick, a first solution comprising 4.2 mmol of AM, 0.10 mmol of DOT, 0.014 mmol of 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid, and 0.003 mmol of AIBN in 1.6 mL of a DMSO / water mixture (80 / 20%v) is prepared. A second solution is prepared, corresponding to the pour, comprising 0.32 mmol of DOT, 0.001 mmol of AIBN in 0.7 mL of DMSO. Both solutions are bubbled with argon to remove dissolved oxygen for 30 min at room temperature. The first solution is heated to 80°C with stirring. The second solution is injected in casting in 6h with (a constant flow rate of 116 qL / h). After 24h, a solution of 0.002 mmol of AIBN in 70 pL of DMSO (degassed with argon) is added to remove residual monomers and the polymerization is stopped after 29h.After cooling to room temperature, the polymer is recovered by precipitation in THF, then centrifuged at 5,000 rpm for 10 minutes. After removal of the liquid fraction, . THF is added and the polymer is suspended in a sonic bath. The P(AM-co-DOT) is then filtered and dried at 40°C under vacuum for 24 h. Polymer 2 is then obtained.

[0163] [Tables 1] Process % Coverage AM % Coverage DOT Final polymer Degraded polymer Mw (g.moF1) D Mw (g.mol1) (% Mw loss) D Classic 64 100 33 900 L25 4 700 (-86%) 5.1 In casting 90 >99 50 500 1.40 4000 (-92%) 3.6

[0164] Table 1: Degradation results of (AM-co-DOT)

[0165] The polymerization process according to the invention allows better conversion and integration of the hydrolyzable functions making it possible to obtain degraded polymers with a more homogeneous dispersity. It is therefore possible to obtain polymer fragments with a lower molecular weight, which results in obtaining a polymer with improved degradability which is subsequently simpler to biodegrade. Example 2 - Cyclic Ketene Acetals

[0166] Polymer 3 - Conventional polymerization

[0167] In a 10 mL round-bottomed flask equipped with a mechanical stirrer, a thermometer, a condenser and an argon gas dipstick, 6.4 mmol of AM, 1.6 mmol of MDO, 0.04 mmol of 4-methyl 2-[(ethoxymethanethioyl)sulfanyl]propanoate and 0.024 mmol of AIBN are introduced into 1 mL of anhydrous DMSO. The medium is bubbled with argon, to remove dissolved oxygen, for 15 min at room temperature. The medium is then heated to 80°C for 6 h with stirring. After cooling to room temperature, the polymer is recovered by precipitation in acetone. The P(AM-co-MDO) is then dried at 50°C for 24 h. Polymer 3 is then obtained.

[0168] Polymer 4 - Casting Polymerization

[0169] In a 10 mL round-bottomed flask equipped with a mechanical stirrer, a thermometer, a condenser, and an argon gas dipstick, a first solution comprising 0.79 mmol of AM, 1.58 mmol of MDO, 0.04 mmol of 4-methyl 2-[(ethoxymethanethioyl)sulfanyl]propanoate, and 0.024 mmol of AIBN in 2 mL of anhydrous DMSO is prepared. A second solution is prepared, corresponding to the pour, comprising 5.5 mmol of AM in 2 mL of anhydrous DMSO. Both solutions are bubbled with argon, to remove dissolved oxygen, for 30 min at room temperature. The first solution is heated to 70°C with stirring. The second solution is injected in casting over 3 hours with (a constant flow rate of 660 pL / h). The polymerization is stopped after 20 hours. After cooling to room temperature, the polymer is recovered by precipitation in acetone. The P(AM-co-MDO) is then dried at 40°C under vacuum for 24 hours. Polymer 4 is then obtained.

[0170] [Tables2] Process % Conv. AM % CûBV. MDO Final polymer Degraded polymer ï B1 Mw, (g.mol1) D Mw (g.mol4) (% Mw loss) B Classic 98 87 30,000 1.25 8,700 (-70%) 5.6 In casting 93,100 41,900 1.40 12,600 (-69%) 3.7

[0171] Table 2: Degradation results of P(AM-co-MDO)

[0172] The polymerization process according to the invention allows better conversion and integration of the hydrolyzable functions, making it possible to obtain degraded polymers with a more homogeneous dispersity. It is therefore possible to obtain polymer fragments with a lower molecular weight, which results in obtaining a polymer with improved degradability which is subsequently simpler to biodegrade.

Claims

Claims

1. Process for preparing a polymer by free-radical casting polymerization of at least two monomers: - at least one monomer A chosen from: (meth)acrylamide, (meth)acrylamide derivatives, (meth)acrylic acid, (meth)acrylic acid derivatives and mixtures thereof; and - at least one cyclic monomer B chosen from: cyclic ketene acetals, thionolactones and mixtures thereof.

2. Process according to claim 1, characterized in that the radical polymerization lasts between 60 minutes and 1440 minutes.

3. Method according to one of the preceding claims, characterized in that the monomers A and B are added during casting, at a constant flow rate.

4. Method according to one of the preceding claims, characterized in that the monomers A and B are added separately, in separate castings.

5. Method according to one of the preceding claims, characterized in that monomer A has a casting time different from the casting time of monomer B.

6. Method according to one of the preceding claims, characterized in that the method has a molar ratio of monomer A:monomer B of between 50:50 and 98:

2.

7. Method according to one of the preceding claims, characterized in that the monomer B is a mixture of two different monomers: Bi and B2.

8. Method according to claim 7, characterized in that the method has a molar ratio monomer A:monomer B i:monomer B2 of between 50:30:20 and 93:5:2, the monomers being added separately, in 3 separate flows.

9. A method according to claim 7 or 8, characterized in that the monomer Bi is a cyclic ketene acetal, and in that the monomer B2 is a thionolactone.

10. Method according to one of claims 7 to 9, characterized in that the casting of monomer B2 begins at the end of the casting of monomer B.

11.

12. i- Polymer obtained according to one of the preceding claims. Polymer according to claim 11, characterized in that the monomer B is a cyclic ketene acetal chosen from: 2-methylene-l,3-dioxepane, 5,6-benzo-2-methylene-l,3-dioxepane, 2-methylene-4-phenyl-l,3-dioxolane, 2-methylene-l,3,6-trioxocane and mixtures thereof.

13. Polymer according to claim 11, characterized in that the monomer B is a thionolactone chosen from: dibenzo[c,e]oxepine(7H)-5-thione, e-thionocaprolactone, 3,3-dimethyl-2,3-dihydro-5Hbenzo[e][l,4]dioxepine-5-thione and mixtures thereof.

14. Polymer according to one of claims 11 to 13, characterized in that the polymer is a polymer of a monomer A and a monomer B, - monomer A being chosen from: (meth)acrylamide, (meth)acrylamide derivatives, (meth)acrylic acid, (meth)acrylic acid derivatives, and mixtures thereof; - monomer B being a mixture of monomer B i and monomer B2, * Bi being at least one monomer chosen from cyclic ketene acetals; * B2 being at least one monomer chosen from thionolactones.

15. Use of a polymer according to one of claims 11 to 14 in the recovery of hydrocarbons; in the drilling or cementing of wells; in the stimulation of hydrocarbon wells; in the treatment of water in an open circuit, in a closed circuit or in a semi-closed circuit; in the treatment of fermentation musts; in the treatment of sludge; in construction; in the manufacture of paper or cardboard; in the field of batteries; 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 geothermal energy; in the manufacture of hygienic diapers; or in agriculture.

16. Use of a polymer according to one of claims 11 to 14 as a flocculant, coagulant, binding agent, fixing agent, viscosity reducing agent, thickening agent, absorbent agent, friction reducing agent, drainage agent, charge retention agent, dehydrating agent, conditioning agent, stabilizing agent, film-forming agent, sizing agent, superplasticizing agent, clay inhibitor or dispersant.