Process for functionalizing polyolefins by reactive extrusion

Abstract

The invention relates to a process for preparing at least one functionalized polyolefin (I) by reactive extrusion, under inert conditions or non-inert conditions. The invention also relates to a polyolefin functionalized with oxime groups (I-A), as well as a polyolefin functionalized with carbonyl groups (I-B) obtained in accordance with the process according to the invention.

Description

Title of the invention: Process for functionalizing polyolefins by reactive extrusion

[0001] Background of the invention

[0002] The invention relates to a process for functionalizing polyolefins by reactive extrusion via the introduction of oxime or carbonyl groups.

[0003] Object and summary of the invention

[0004] Currently, plastic pollution is constantly increasing and has therefore become a major problem. Indeed, this source of pollution has particularly harmful effects on waterways, seas and oceans, and on marine animals.

[0005] Approximately one-third of plastics produced are polyolefins. This plastic waste is generally made from polymers designed to be resistant, both mechanically and chemically. Their recycling and recovery are therefore difficult.

[0006] Nowadays, plastic waste is often either landfilled, incinerated, or mechanically recycled. Landfilling carries the risk of dispersing lighter plastics due to wind. Incineration has the disadvantage of releasing toxic products, including greenhouse gases. For example, HCl is released when PVC is burned. It is therefore necessary to find alternatives for closed-loop recycling of plastic waste or to "upcycle" it, that is, to transform it into smaller, more valuable molecules.

[0007] Currently, plastic recycling is primarily mechanical: the polymer is extruded for reuse. The drawback of this process is that the polymer degrades with repeated extrusions, leading to a decrease in its mechanical properties. Consequently, the polymer can no longer be reused after a certain number of extrusions. Furthermore, contaminated plastics are very difficult to recycle in this way.

[0008] Another solution currently being researched is the chemical or enzymatic degradation of polymers.

[0009] Regarding the enzymatic degradation of polymers, one notable example is the enzymatic degradation of PET (Nature, vol. 580 (2020), 216-219). This method, using enzymes, allows for the depolymerization of at least 90% of PET into monomers within 10 hours. These monomers can then be reused, for example, to synthesize new PET. While this solution appears effective, it is only applicable to PET, and not to polyolefins, which contain only hydrocarbon chains that are less reactive than the ester groups of PET.

[0010] Regarding chemical degradation, a widely studied pathway is the introduction of polar groups, and in particular ester groups, via prior oxidation of the parent polymer introducing carbonyl or hydroxyl functions, followed by a Baeyer-Villiger reaction (Nature Communications 2024, 15, 9188). However, the preliminary step is not well controlled because it is not selective.

[0011] Another method was reported by Conk et al. (Science, 377, 1561-1566, 2022), which describes the production of propylene by partial dehydrogenation of polyethylene and tandem ethanolyse-isomerization. This method is particularly interesting because it yields highly valuable products. However, this method involves the use of expensive catalysts: an iridium or platinum-zinc complex for polyethylene dehydrogenation, and a second-generation Hoveyda-Grubbs metathesis catalyst and [PdP(t-Bu)3(p-Br)]2 for isomerization. Furthermore, high heating and pressure are required.

[0012] The Applicant therefore sought an easy-to-implement alternative method for recycling and valorizing polyolefins. Initially, the Applicant focused particularly on functionalizing these polyolefins with oxime groups, with the aim of utilizing the specific reactivity of these oxime groups to valorize the polyolefins. Indeed, as explained in the document by Rykaczewski et al. (Nature Synthesis, 2022, vol. 1, 24-36), oxime groups exhibit such reactivity towards transition metals and photocatalysis that they constitute reagents of choice for the synthesis of nitrogen heterocycles, amino alcohols, and amines, among others.

[0013] In order to introduce oxime groups into polyolefins, the Applicant sought a method that was easy to implement and efficient. Advantageously, the method should be reproducible. Advantageously, the method should be usable with various polyolefins, and in particular different grades of polyethylene, polypropylene, and / or ethylene-propylene copolymer, possibly hydroxylated at the terminal position.

[0014] The photochemical transformation allowing the introduction of an oxime group onto an alkane has been studied, notably for the synthesis of caprolactam, a precursor of Nylon-6. For example, the Toray process (US 3,090,739) involves the preparation of cyclohexanone oxime by photochemically introducing an oxime unit into cyclohexane using NOCI and HCl under UV light (mercury vapor lamp). The cyclohexanone oxime is then transformed into caprolactam under acidic conditions. This process has the disadvantage of using corrosive NOCI and HCl. To overcome this problem, the use of less corrosive alternative reagents has been investigated. In particular, it has been reported, notably in the paper by A. Mackor et al. (Red. Trav. Chim. Pays-Bas, 1969, 88, 1249-1262) and Wysocki et al. (ChemPhotoChem, 2018, 2, 22- 26), the photochemical transformation of cyclohexane into cyclohexanone oxime using tert-butyl nitrite (t-BuONO) and UV irradiation.

[0015] Furthermore, the Applicant described in patent application PCT / FR2024 / 050991 the introduction of oxime groups into polyolefins, followed by a post-functionalization reaction. The oxime group is advantageously introduced under irradiation using a nitrosating agent. Subsequently, the oxime groups present on the functionalized polyolefin can be reacted with these oxime groups to obtain a wide variety of compounds. This method has the advantage of being simple to implement and versatile.

[0016] Other methods for functionalizing polyolefins with various functional groups, including oxime, carbonyl and amide functions, have also been described in Baur et al. (Angew. Chem. Int. Ed. 2023, 62, e202310990), Lu et al. (Angew. Chem. Int. Ed. 2024, e202410849), Shi et al. (J. Am. Chem. Soc. 2023, 145, 21527-21537), Williamson et al. (Angew. Chem. Int. Ed, 2019, 58, 8654-8668), CN 115 232 231, and US 6,333,078. The production processes are complex and / or require several steps and / or expensive reagents and / or catalysts. These processes are therefore difficult to scale up to an industrial level.

[0017] The Applicant continued its research, seeking to develop new methods for functionalizing polyolefins to enhance their value. These methods should be simple and efficient to implement, preferably scalable to industrial production, and capable of yielding a wide variety of compounds. It was in this context that the Applicant became interested in reactive extrusion. To date, the Applicant is unaware of any documents describing the introduction of functionalities into polyolefins by reactive extrusion. The Applicant therefore undertook a research project to identify and develop a method for functionalizing polyolefins using reactive extrusion.

[0018] More particularly, the invention relates to the preparation of at least one functionalized polyolefin (I) comprising, preferably consisting of, the following steps: 1) possess at least one polyolefin of formula II: with : - RI representing a methyl, ethyl, or n-butyl group, - R2 representing H, CH3 or OH, - n representing an integer ranging from 0 to 100000, - m representing an integer ranging from 0 to 100000, and - n + m + 0, and 2) react at least one polyolefin II with at least one nitrosating agent III in an extruder.

[0019] This preparation method has the advantage of being simple to implement and does not require the use of corrosive or toxic reagents. The functionalized polyolefin thus obtained does not require a purification step. Furthermore, the method according to the invention makes it possible to obtain a polyolefin functionalized with oxime groups or with carbonyl groups, depending on the operating conditions chosen.

[0020] The preparation process according to the invention has one or more of the following characteristics: - at least one nitrosation agent III is chosen from: , , (III-C), and their mixtures, with: - R4 and R5 being identical or different and independently representing a group chosen from (Cl-C6)alkyl, N[(Cl-C6)alkyl]3, CO[(Cl-C6)alkyl], SO2Ph, CO-Ph-CF3 - or R4 and R5 together forming a (C5-C10) cycloalkylene group possibly substituted by one or more (C1-C6) linear or branched alkyl groups, or an -SO2-Ph-C(CH3)2- group, or a -CO-Ph-CO- group, - R6 representing a phthalimide group or a (Cl-C6) linear or branched alkyl group, and - R7 representing an aromatic or heteroaromatic group possibly perfluorinated; - at least one nitrosating agent is chosen from: their mixtures; - the molar ratio of nitrosating agent(s) III / repeat units of polyolefin(s) II ranges from 0.01 to 2, preferably from 0.1 to 0.5; - at least one polyolefin II is chosen from polyethylene, polypropylene possibly hydroxylated in the terminal position, an ethylene-propylene copolymer possibly hydroxylated in the terminal position, and mixtures thereof; - in step 2), the temperature within the extruder is greater than or equal to the melting temperature of at least one polyolefin II, and less than the degradation temperature of at least one nitrosating agent III; - step 2) is carried out under inert conditions, in order to obtain at least one polyolefin functionalized with IA oxime groups; - the process further includes a step 3) subsequent to step 2), said step 3) consisting of reacting the oxime groups present in at least one polyolefin functionalized with IA oxime groups; - step 3) includes the reaction of at least one acid chloride with the oxime groups of at least one polyolefin functionalized with IA oxime groups; - step 3) includes a Beckmann rearrangement; - step 3) includes an acid hydrolysis reaction, subsequent to the Beckmann rearrangement; - step 3) includes the reduction of oxime groups of at least one polyolefin functionalized with IA oxime groups; - step 3) includes the reaction of at least one isocyanate with the oxime groups of at least one polyolefin functionalized with IA oxime groups; - step 3) includes a polymer chain grafting reaction, such as polyethylene glycol or polycaprolactone chains; - step 3) includes an acid hydrolysis reaction of at least one polyolefin functionalized with oxime groups IA, in order to obtain at least one polyolefin functionalized with carbonyl groups IB; - Step 2) is carried out in the presence of air, in order to obtain at least one polyolefin functionalized with IB carbonyl groups; - the process includes a step 4), subsequent to step 2) and subsequent to step 3) when the latter is carried out, consisting of reacting the carbonyl groups present in at least one functionalized polyolefin with carbonyl groups IB; - step 4) includes a Baeyer-Villiger reaction; and - step 4) includes a Baeyer-Villiger reaction followed by a methanolysis reaction.

[0021] The invention further relates to a polyolefin functionalized with oxime groups obtained according to the process of the invention, as well as a polyolefin functionalized with carbonyl groups obtained according to the process of the invention. The functionalized polyolefins obtained according to the processes of the invention have the advantage of being pure or nearly pure and requiring little or no purification, and / or of being obtainable in various physical forms (filaments, granules, etc.), and / or of being directly moldable.

[0022] Brief description of the drawings

[0023] Other features and advantages of the present invention will become apparent from the description given below, with reference to the attached drawings which illustrate an example of an embodiment without any limiting character.

[0024] Figure 1 is the spectrum XH NMR of carbonyl functionalized HDPE IBl.

[0025] Figure 2 is the spectrum X H NMR of carbonyl functionalized HDPE IAl.

[0026] Figure 3 is the spectrum X H NMR of functionalized HDPE ICl ester.

[0027] Figure 4 is the spectrum X H NMR of carbonyl functionalized LLDPE IB-3.

[0028] Figure 5 is the spectrum X H NMR of carbonyl functionalized HDPE IB-4.

[0029] Figure 6 is the spectrum X H NMR of carbonyl functionalized LDPE IB-5.

[0030] Detailed description of the invention

[0031] The invention relates to a reactive extrusion process for preparing at least one functionalized polyolefin I from at least one polyolefin II. More specifically, the process preferably comprises the following steps: 1) have at least one polyolefin II with the following formula: with : - Rl representing a methyl, ethyl or n-butyl group, - R2 representing H, CH3 or OH, - n representing an integer ranging from 0 to 100000, - m representing an integer ranging from 0 to 100000, and - n + m + 0. 2) react at least one polyolefin II with at least one nitrosating agent III in an extruder.

[0032] In the context of the invention, "at least one polyolefin II" means exactly one polyolefin II or a mixture of several different polyolefins, each of formula II. In what follows, and unless otherwise specified, reference is made to "the polyolefin" instead of "the at least one polyolefin" for the sake of simplicity, but it is understood that one or more polyolefins II may be used without departing from the scope of the invention.

[0033] According to a preferred embodiment, the polyolefin of formula II is such that Rl represents CH3, R2 represents H, CH3 or OH, n represents an integer from 0 to 100000, and m represents an integer from 0 to 100000, it being understood that n and m are not both equal to 0. In other words, according to this embodiment, polyolefin II is either a homopolymer of ethylene or propylene, optionally hydroxylated at the terminal position, or a copolymer of ethylene and / or propylene, optionally hydroxylated at the terminal position.

[0034] According to a first embodiment, polyolefin II is a homopolymer. In other words, according to this embodiment, polyolefin II is either polyethylene (i.e., n=0 and m^O), or polypropylene or polybutylene or polyhexylene possibly hydroxylated in terminal position (i.e. m=0 and n^O, and RI represents respectively Me, Et or Bu).

[0035] According to this first embodiment, the polyethylene can be low-density polyethylene or high-density polyethylene.

[0036] In the context of the invention, "low-density polyethylene" or LDPE is produced by radical polymerization at high pressures (typically from 500 atm to 3000 atm) and high temperatures (typically from 200 °C to 300 °C) (see Aggarwal et al., Chem. Rev. 1957, 57, 4, 665-742, and Jubinville et al., Sustain. Mater. Technol. 25, 2020, e00188). This type of polymerization generates numerous branches, both long and short. These are due to inter- and intramolecular chain transfers, respectively, during polymerization. The density of LDPE ranges from 0.915 to 0.933 g / cm³. 3 .

[0037] Within the framework of the invention, the density of the different polymers can be determined according to ISO 1183-3: 1999.

[0038] In the context of the invention, "high-density polyethylene" or HDPE can be synthesized at lower pressures (typically from 1 atm to 300 atm), for example, in the presence of a Ziegler-Natta metal catalyst (see Aggarwal et al., Chem. Rev. 1957, 57, 4, 665-742, and Jubinville et al., Sustain. Mater. Technol. 25, 2020, e00188). This process yields a linear polyethylene with little or no branching. The density of HDPE ranges from 0.93 to 0.97 g / cm³. 3 .

[0039] High-density polyethylene (HDPE) and low-density polyethylene (LDPE) differ in their degree of branching and their level of crystallinity. High-density polyethylene is more crystalline than low-density polyethylene.

[0040] According to this first embodiment, the polypropylene is preferably an isotactic polypropylene, that is to say that the distribution of the RI substituents is uniform along the main chain of the polymer.

[0041] According to a second embodiment, polyolefin II is a copolymer. In other words, the polyolefin is such that n^0 and m^0. The copolymer can be a block or statistical copolymer.

[0042] Preferably according to this embodiment, polyolefin II is either a copolymer of ethylene and propylene, possibly hydroxylated, or a linear low-density polyethylene (LLDPE).

[0043] In the context of the invention, a "linear low-density polyethylene" or LLDPE is a copolymer of ethylene with an olefin selected from propylene, butylene, pentylene, hexylene, and octylene. Such a polymer can be obtained by the Ziegler-Natta process (see Aggarwal et al., Chem. Rev. 1957, 57, 4, 665-742, and Jubinville et al., Sustain. Mater. Technol. 25, 2020, e00188). The density of LLDPE ranges from 0.92 to 0.94 g / cm³. 3 .

[0044] According to an advantageous embodiment of the invention, the degree of crystallinity (mass or volume) of polyolefin II ranges from 40% to 95%, preferably from 40% to 80%. The degree of crystallinity is a measure of the proportion of crystalline material in the sample studied. Within the scope of the invention, the degree of crystallinity can, for example, be determined by differential scanning calorimetry (DSC) by the ratio between the enthalpy of fusion measured for the sample under consideration and the enthalpy of fusion of a 100% crystalline sample.

[0045] According to an advantageous embodiment of the invention, the melting temperature of polyolefin II ranges from 120 °C to 140 °C. Within the scope of the invention, the melting temperature of polyolefin II can be measured by thermogravimetric analysis (TGA) or by differential scanning calorimetry (DSC). In the context of the invention, the melting temperature corresponds to the temperature measured at the maximum peak of the thermal phenomenon corresponding to melting.

[0046] Polyolefin can be of commercial origin, synthetic, or derived from waste.

[0047] The second step of the process according to the invention consists of reacting at least one polyolefin II with at least one nitrosating agent III in order to obtain at least one functionalized polyolefin I.

[0048] In the context of the invention, "functionalized polyolefin" or "functionalized polyolefin with functional groups" means a polyolefin comprising at least one functional group. When the functionalized polyolefin comprises several functional groups, these may be distributed regularly or Statistics on the said functionalized polyolefin. These functional groups can be integrated into a chain of the polymer (i.e., the functional groups are integrated into the polymer chain (on the main chain and / or on the branched chain(s) if present)), and / or be pendant (i.e., the functional groups are substituents). According to a particular embodiment, the distribution of functional groups can be directed by the prior introduction of functional groups that allow for the direction of selectivity during the functional group incorporation reaction.

[0049] By "functional group" we mean an organic group or fragment other than alkyl. Examples of functional groups include: =N-OH (oxime), -C(O)-alkyl, -C(O)O-alkyl, -C(O)-alkylene-OC(O)-alkyl, -C(O)OH, -C(O)-alkylene-OH, -COOH, -NH-C(O)-alkyl, -N(H)-OH, and NH2.

[0050] For the purposes of this invention, alkyl means a hydrocarbon chain - (CH2)n-CH3 with n representing an integer greater than or equal to 0. Typically, n represents an integer from 0 to 18, preferably from 0 to 12, unless otherwise specified.

[0051] By "alkylene" we mean a divalent alkyl group -(CH2) n - with n representing an integer greater than or equal to 0, preferably an integer from 0 to 18, and even better an integer from 0 to 12, unless otherwise specified

[0052] Preferably, nitrosating agent III has the following formula:

[0053] R 3 no (III),

[0054] with R3 representing a group comprising an N, O or S atom bonded to the NO group.

[0055] Preferably, nitrosating agent III is of formula III-a, III-b or III-c as described below.

[0056] The nitrosating agent Ill-a has the following formula:

[0058] with R4 and R5 being identical or different and independently representing a group chosen from (Cl-C6)alkyl, N[(Cl-C6)alkyl]3, CO[(Cl-C6)alkyl], SO2Ph, CO-Ph-CF3, or R4 and R5 together forming a (C5-C10) cycloalkylene group optionally substituted by one or more linear or branched (C1-C6) alkyl groups, or a -SO2-Ph-C(CH3)2- group, or a -CO-Ph-CO- group; preferably R4 and R5 being identical or different and independently representing a group chosen from (Cl-C6)alkyl, N(CH3)3, CO[(Cl-C6)alkyl], SO2Ph, CO-Ph-CF3, or R4 and R5 together forming a (C5-C6) cycloalkylene group optionally substituted by one or more linear or branched (C1-C6) alkyl groups, or a -SO2-Ph-C(CH3)2- group, or a -CO-Ph-CO- group.

[0059] The nitrosating agent Ill-b has the following formula:

[0061] with R6 representing a phthalimide group or a linear or branched (Cl-C6)alkyl group, preferably R6 representing a linear or branched (Cl-C6)alkyl group.

[0062] The nitrosating agent III-c has the following formula:

[0064] with R7 representing an aromatic or heteroaromatic group possibly perfluorinated, preferably R7 representing an aromatic or heteroaromatic group perfluorinated, more preferably R7 representing a heteroaromatic group perfluorinated.

[0065] Preferably, at least one nitrosating agent III is chosen from:

[0075] and their mixtures.

[0076] According to a preferred embodiment, only one nitrosating agent is used.

[0077] According to a preferred embodiment, nitrosating agent III is tert-butylnitrite III-9.

[0078] Preferably, the molar ratio of nitrosating agent III to repeat units of polyolefin(s) II ranges from 0.01 to 2, preferably from 0.1 to 0.5.

[0079] The term "repeat unit" or "repeat unit" of a polymer refers to the smallest constituent unit whose repetition describes the polymer. In the case of a copolymer, this unit is made up of several distinct repeat units.

[0080] Within the scope of the invention, the number of moles of repeating units of a polymer is estimated using the method detailed in Fazekas et al., Science 375, 545-550 (2022): the number of moles of repeating units of a polymer (homopolymer or copolymer) is calculated by the ratio between the mass of polymer involved and the molar mass of the repeating unit (if homopolymer) or repeating units (if copolymer). For the specific case of polyolefins functionalized with oxime groups, the following is considered for determining the number of moles of units of repetition, that all the repetition units are functionalized with oxime groups: the number of moles of repetition units of a polyolefin functionalized with oxime groups is then equal to the ratio between the mass of polyolefin functionalized with oxime groups and the molar mass of the repetition units including an oxime group.

[0081] In the context of the invention, the reaction of at least one polyolefin II with the nitrosating agent III is carried out in an extruder. Various types of extruders can be used in the context of the invention, and in particular single-screw extruders, twin-screw extruders (coaxial twin-screw, conical twin-screw, co-rotating or counter-rotating twin-screw (with or without meshing), or parallel twin-screw), and triple-screw extruders, for example. The extruder length and rotational speed can be adjusted by those skilled in the art.

[0082] Preferably, the temperature within the extruder is greater than or equal to the melting temperature of at least one polyolefin II. Preferably, the temperature within the extruder is lower than the degradation temperature of at least one nitrosating agent III. In a particularly preferred embodiment, the temperature within the extruder is greater than or equal to the melting temperature of at least one polyolefin II, and lower than the degradation temperature of at least one nitrosating agent III. Preferably, the temperature within the extruder is uniform or substantially uniform (i.e., identical or substantially identical at every point in the extruder), although it is conceivable to use an extruder having zones with distinct temperatures without departing from the scope of the invention.

[0083] Preferably, the pressure inside the extruder is approximately 1 atm.

[0084] Preferably, the reaction of at least one polyolefin II with nitrosating agent III (step 2) is carried out without a solvent. Preferably, the reaction of at least one polyolefin II with nitrosating agent III (step 2) is carried out without a catalyst. Preferably, step 2) is carried out only in the presence of at least one polyolefin and at least one nitrosating agent.

[0085] Preferably, at least one polyolefin II is introduced at the beginning of the extruder. Preferably, at least one polyolefin II is introduced into the extruder before the at least one nitrosating agent III, meaning that at least one nitrosating agent III is added to at least one polyolefin present in the extruder. Preferably, the at least one nitrosating agent III is introduced when the at least one polyolefin II is in a molten state, meaning that the at least one polyolefin II is placed in an area of ​​the extruder that is at a temperature greater than or equal to its melting point for a time sufficient to allow it to melt, and then the at least one nitrosating agent III is added to the at least one polyolefin II. In a first embodiment, the at least one nitrosating agent III is added continuously to the at least one polyolefin II. Alternatively, in another embodiment, the at least one nitrosating agent III is added sequentially, according to a duration and sequence of addition that can be determined by those skilled in the art.

[0086] Step 2) of the reaction of at least one polyolefin II with at least one nitrosating agent III in the extruder can be carried out under inert conditions or under non-inert conditions (i.e. in the presence of air). The products obtained are then different.

[0087] Within the framework of the invention, a reaction carried out under "inert" conditions means that it is performed in the absence of O2, typically under an atmosphere of N2 or Ar, and preferably under anhydrous conditions. To achieve this, a continuous flow of N2 or Ar within the extruder can be implemented.

[0088] According to a first embodiment, the reaction of at least one polyolefin II with at least one nitrosating agent III in the extruder (step 2) is carried out under inert conditions. According to this embodiment, at least one polyolefin functionalized with oxime groups IA is then obtained at the end of step 2). In other words, step 2) allows the at least one polyolefin II to be functionalized with oxime groups.

[0089] In the context of the invention, "oxyme-functionalized polyolefin" or "nitrosylated polyolefin" means a polyolefin comprising at least one oxime group or substituent. When the oxime-functionalized polyolefin comprises several oxime groups or substituents, these groups or substituents may be distributed regularly or statistically throughout said oxime-functionalized polyolefin. In a particular embodiment, the distribution of the oxime groups may be directed by the prior introduction of functional groups that allow the selectivity to be directed during the initiation reaction of oxime groups.

[0090] By "oxime group", we mean a =N-OH group.

[0091] Within the framework of the invention, "functionalizing a polyolefin with oxime groups", "introducing oxime groups onto a polyolefin" and "nitrosylating a polyolefin" are synonymous, and refer to the introduction of oxime group(s) (=N-OH) onto the polyolefin, onto the main chain and / or onto the branched chain(s) if present.

[0092] In other words, according to this first embodiment, the process according to the invention comprises the following steps: 1) have at least one polyolefin of formula (II): with : - Rl representing a methyl, ethyl or n-butyl group, - R2 representing H, CH3 or OH, - n representing an integer ranging from 0 to 100000, - m representing an integer ranging from 0 to 100000, and - n + m + 0, and 2) react at least one polyolefin II with at least one nitrosating agent III in an extruder under inert conditions in order to obtain at least one polyolefin functionalized with oxime groups IA.

[0093] According to this first embodiment, the process may further include a step 3) subsequent to step 2), said step 3) comprising, and preferably consisting of, reacting the oxime groups present in at least one polyolefin functionalized with IA oxime groups. According to this embodiment, the process then comprises, preferably consists of, the following steps: 1) have at least one polyolefin of formula (II): with : - RI representing a methyl, ethyl, or n-butyl group, - R2 representing H, CH3 or OH, - n representing an integer ranging from 0 to 100000, - m representing an integer ranging from 0 to 100000, and - n + m + 0, 2) react at least one polyolefin II with at least one nitrosating agent III in an extruder under inert conditions to obtain at least one polyolefin functionalized with oxime groups IA, and 3) react the oxime groups present in at least one polyolefin functionalized with IA oxime groups.

[0094] Advantageously, in step 3, all oxime groups in the polyolefin functionalized with present IA oxime groups react. However, it is possible to react only some of them (for example, by introducing limiting reagents), or even to react some of the oxime groups in a first reaction and a second part (or more) in a second reaction (or more), without departing from the scope of the invention.

[0095] Various reactions can be considered in step 3): reduction, Beckmann rearrangement, hydrolysis, addition of isocyanate or acid chloride, grafting of PEG or PCL chains, etc. These reactions can be carried out in an extruder or in a reactor. If these reactions are carried out in an extruder, it can be the one used in step 2), (the reagents needed for step 3) are then added to at least one polyolefin functionalized with oxime IA groups present in the extruder used in step 2), or another extruder.

[0096] Step 3) may include one or more reactions of the oxime groups present in at least one polyolefin functionalized with IA oxime groups, or even subsequent reactions to one or more reactions of said oxime groups.

[0097] According to a first embodiment, step 3) preferably comprises a reaction of an acid chloride with the oxime groups of the polyolefin functionalized with oxime groups IA. Preferably, this reaction is carried out in a basic medium, for example in the presence of triethylamine, N,N-diisopropylethylamine, or 1,4-diazabicyclo[2.2.2.]octane. Preferably, this reaction is carried out at a temperature that allows the solubilization of the polyolefin functionalized with oxime groups II, that is, a temperature generally ranging from 20°C to 70°C, preferably from 40°C to 60°C. Preferably, this reaction is carried out in a reactor.

[0098] According to this embodiment, this step advantageously includes a step of contacting the polyolefin functionalized with oxime groups IA with an acid chloride of the following formula IV:

[0100] with R8 representing a (Cl-C6)alkyl group, a (Cl-C6)alkene group, an aromatic group possibly substituted by one or more (Cl-C6)alkyl or (Cl-C6)perfluoroalkyl groups.

[0101] By "alkene" we mean an alkyl group containing at least one C=C double bond.

[0102] Preferably, R8 represents Ph, p-CF3-Ph, a vinyl group (CH=CH2).

[0103] Preferably, the molar ratio of repeat units of polyolefin functionalized with oxime groups IA / acid chloride IV ranges from 1 / 0.9 to 1 / 1.3, preferably from 1 / 1 to 1 / 1.2, and even better is 1 / 1.1.

[0104] Advantageously, in this reaction, the polyolefin functionalized with oxime groups IA is dissolved in at least one solvent, possibly by heating to facilitate the solubilization of the polyolefin functionalized with oxime groups IA. Then the acid chloride IV and the base are added.

[0105] According to a second embodiment, step 3) preferably comprises a Beckmann rearrangement reaction. The Beckmann rearrangement is known to allow the transformation of oxime group(s) into amide group(s). This reaction thus yields a functionalized polyolefin. with amide groups. According to this embodiment, the amide functions are incorporated into the polymer chain, that is to say that the polymer chain is interrupted by amide functions.

[0106] This Beckmann rearrangement reaction is advantageously carried out in an acidic medium. This Beckmann rearrangement reaction, and the operating conditions that can be used, are well known to those skilled in the art (see, for example, New J. Chem., 2020, 44, 18530-18572) and will not be detailed here. Preferably, this reaction is carried out in a reactor.

[0107] It is then possible to perform a hydrolysis reaction of the amide groups. The amide groups are then transformed into carboxylic acid groups (COOH). The hydrolysis reaction of amide groups is usually carried out in an acidic medium. This reaction thus makes it possible to obtain carboxylic acids of varying chain lengths.

[0108] According to a third embodiment, step 3) preferably comprises a reduction reaction of oxime groups to hydroxylamine groups. This reaction then yields a polyolefin functionalized with hydroxylamine groups.

[0109] The reducing agents and operating conditions that can be used to reduce oxime groups to hydroxylamine groups are known in the prior art. NaBH3CN is an example of a reducing agent. Preferably, this reaction is carried out in a reactor.

[0110] According to a fourth embodiment, step 3) preferably comprises a reduction reaction of oxime groups to amine groups. This reaction then yields a polyolefin functionalized with amine groups. [YES] The reducing agents and operating conditions that can be used to reduce oxime groups to amine groups are known in the prior art. LiAl₂O₅ is an example of a reducing agent. Preferably, this reaction is carried out in a reactor.

[0112] According to a fifth embodiment, step 3) preferably comprises a reaction of an isocyanate with the oxime groups of the polyolefin functionalized with oxime IA groups. Preferably, this reaction is carried out by heating the reaction mixture to a temperature enabling the solubilization of the polyolefin functionalized with oxime IA groups, i.e. for example at a temperature ranging from 50 °C to 110 °C.

[0113] According to this embodiment, this step advantageously includes a step of contacting the polyolefin functionalized with oxime groups IA with an isocyanate of formula V:

[0115] with R9 and RIO being identical or different and independently representing (C1-C6) alkyl, (C6-C10) aryl, or an isocyanate NCO group; or R9 and RIO together represent a (C5-C8) cycloalkylene group.

[0116] Preferably, the molar ratio of polyolefin functionalized with oxime groups IA / isocyanate V ranges from 1 / 0.8 to 1 / 1.2, preferably from 1 / 0.9 to 1 / 1.1, and even better is 1 / 1.

[0117] Preferably, this reaction is carried out in a reactor.

[0118] According to a sixth embodiment, step 3) comprises, or even consists of, a PEG (polyethylene glycol) chain grafting reaction. In this embodiment, this step advantageously includes a step of contacting the polyolefin functionalized with oxime groups IA with at least one polyethylene glycol derivative comprising at least one reactive function capable of reacting under the reaction conditions with at least one oxime function of the polyolefin functionalized with oxime groups IA. For the purposes of the invention, a polyethylene glycol "derivative" is a polyethylene glycol onto which one or more substituents or functional groups have been introduced.In the context of the invention, the reactive function of the polyethylene glycol derivative is not a hydroxyl (OH) function present on the polyethylene glycol, but another function capable of reacting under the reaction conditions with at least one oxime function of the polyolefin functionalized with IA oxime groups. According to a preferred embodiment, this step includes the. The polyolefin functionalized with oxime groups IA is contacted with a polyethylene glycol derivative comprising at least one reactive function capable of reacting under the reaction conditions with at least one oxime function of the polyolefin functionalized with oxime groups IA. Such a polyethylene glycol derivative comprising at least one reactive function may, for example, be a polyethylene glycol acid chloride or a polyethylene glycol comprising at least one carboxylic acid function. Advantageously, the reactive function(s) of the polyethylene glycol derivative are terminal, i.e., at the end of the chain.

[0119] Preferably, this reaction is carried out in the presence of a solvent. Preferably, this reaction is carried out by heating the reaction mixture to a temperature that allows the solubilization of the polyolefin functionalized with IA oxime groups, i.e., for example, to a temperature ranging from 50 °C to 110 °C. Preferably, this reaction is carried out in a reactor.

[0120] Advantageously, polyethylene glycol or its derivative is introduced in excess. According to this embodiment, the molar ratio of reactive functions of the polyethylene glycol derivative to oxime functions of the polyolefin functionalized with 1A oxime groups ranges from 1.1:1 to 10:1, and is preferably 10:1. In the context of the invention, the number of moles of reactive functions of the polyethylene glycol derivative is determined as detailed in Hövelmann et al., Macromolecules 2017, 50, 4169-4179. In the context of the invention, the number of moles of oxime functions of the polyolefin functionalized with II oxime groups is determined by the following formula:

[0122] with: noximes IA representing the number of oxime functions in the polyolefin functionalized with oxime groups IA, - mi-A representing the mass of polyolefin functionalized with I-A oxime groups, - P representing the percentage of oxime functionalization of the polyolefin functionalized with IA oxime groups, - Unit iA representing the molar mass of the unit(s) of repetitions without oxime function of the polyolefin functionalized with IA oxime groups (28.05 g / mol if CH2CH2).

[0123] According to a seventh embodiment, step 3) comprises, or even consists of, a PCL (polycaprolactone) chain grafting reaction. In this embodiment, this step advantageously includes a step of contacting the polyolefin functionalized with α1 oxime groups with β-caprolactam. This reaction advantageously takes place in the presence of a catalyst capable of catalyzing the ring-opening polymerization of β-caprolactam, such as stannous octanoate, for example.

[0124] Preferably, this reaction is carried out in the presence of a solvent. Preferably, this reaction is carried out by heating the reaction mixture, for example to a temperature ranging from 50 °C to 190 °C, and typically from 100 °C to 170 °C, or even from 120 °C to 150 °C. Preferably, this reaction is carried out in a reactor.

[0125] According to an eighth embodiment, step 3) includes, or even consists of, a hydrolysis reaction, in order to convert the oxime groups to =0, and thus obtain at least one polyolefin functionalized with carbonyl groups IB.

[0126] Typically, the hydrolysis reaction is carried out by adding water, possibly mixed with a water-miscible solvent such as acetone, formaldehyde, or 2,2,2-trifluoroacetophenone, in an acidic or basic medium. Preferably, this reaction is performed in a reactor.

[0127] For the purposes of this invention, a "carbonyl-functionalized polyolefin" is defined as a polyolefin comprising at least one carbonyl group or substituent. When the carbonyl-functionalized polyolefin comprises several carbonyl groups or substituents, these groups or substituents may be distributed regularly or statistically throughout the carbonyl-functionalized polyolefin. These functional groups may be integrated into the main chain and / or onto the branched chain(s) if present. In a particular embodiment, the distribution of the carbonyl groups may be directed by the prior introduction of functional groups that guide the selectivity during the oxime incorporation reaction.

[0128] By "carbonyl group" we mean a -C(O)- group.

[0129] According to this eighth embodiment, the process may further include a step 4) subsequent to step 3), said step 4) preferably comprising reacting the carbonyl groups present in at least one functionalized polyolefin with carbonyl groups IB. According to this embodiment, the process then preferably comprises the following steps: 1) possess at least one polyolefin of formula (II): with : - RI representing a methyl, ethyl, or n-butyl group, - R2 representing H, CH3 or OH, - n representing an integer ranging from 0 to 100000, - m representing an integer ranging from 0 to 100000, and - n + m + 0, 2) react at least one polyolefin II with at least one nitrosating agent III in an extruder under inert conditions in order to obtain at least one polyolefin functionalized with oxime groups IA, 3) hydrolyze the oxime groups present in at least one polyolefin functionalized with αI oxime groups, in order to obtain at least one polyolefin functionalized with IB carbonyl groups, and 4) react the carbonyl groups present in at least one polyolefin functionalized with carbonyl groups IB.

[0130] Advantageously, in step 3, all oxime groups in the polyolefin functionalized with present IA oxime groups react. However, it is possible to react only some of them (for example, by introducing limiting reagents), or even to react some of the oxime groups in a first reaction and a second part (or more) in a second reaction (or more), without departing from the scope of the invention.

[0131] According to a second embodiment, the reaction of at least one polyolefin II with at least one nitrosating agent III in the extruder (step 2) of the process according to the invention) is carried out under non-inert conditions, i.e. in the presence of oxygen and / or under non-anhydrous conditions, and typically in the presence of air. According to this embodiment, at least one polyolefin functionalized with carbonyl groups IB is then obtained at the end of step 2). In other words, step 2) then allows to functionalize at least one polyolefin II with carbonyl groups.

[0132] Within the framework of the invention, "functionalizing a polyolefin with carbonyl groups" and "introducing carbonyl groups onto a polyolefin" are synonymous, and refer to the introduction of carbonyl group(s) onto the polyolefin, onto the main chain and / or onto the branched chain(s) if present.

[0133] In other words, according to this second embodiment, the process according to the invention comprises the following steps: 1) have at least one polyolefin of formula (II): with : - Rl representing a methyl, ethyl or n-butyl group, - R2 representing H, CH3 or OH, - n representing an integer ranging from 0 to 100000, - m representing an integer ranging from 0 to 100000, and - n + m + 0, and 2) react at least one polyolefin II with at least one nitrosating agent III in an extruder under non-inert conditions in order to obtain at least one polyolefin functionalized with carbonyl groups IB.

[0134] According to this second embodiment, the process may further include a step 4) subsequent to step 2), said step 4) preferably comprising reacting the carbonyl groups present in at least one functionalized polyolefin with carbonyl groups IB. According to this embodiment, the process then preferably comprises the following steps: 1) have at least one polyolefin of formula (II): with : - RI representing a methyl, ethyl, or n-butyl group, - R2 representing H, CH3 or OH, - n representing an integer ranging from 0 to 100000, - m representing an integer ranging from 0 to 100000, and - n + m + 0, 2) react at least one polyolefin II with at least one nitrosating agent III in an extruder under non-inert conditions to obtain at least one polyolefin functionalized with carbonyl groups IB, and 4) react the carbonyl groups present in at least one polyolefin functionalized with carbonyl groups IB.

[0135] Advantageously, in step 4, all the carbonyl groups in the polyolefin functionalized with present IB carbonyl groups react. However, it is possible to react only some of them (for example, by introducing limiting reagents), or even to react some of the carbonyl groups in a first reaction and a second part (or more) in a second reaction (or more), without departing from the scope of the invention.

[0136] Step 4) may include one or more reactions of the carbonyl groups present in at least one polyolefin functionalized with IB carbonyl groups. Step 4) may include one or more reactions of the carbonyl groups present in at least one polyolefin functionalized with IB carbonyl groups, or even reactions subsequent to one or more reactions of said carbonyl groups.

[0137] Various reactions involving the reaction of carbonyl functions of at least one polyolefin functionalized with carbonyl groups IB (obtained directly under non-inert conditions at the end of step 2), or obtained at the end of step 3) by acid hydrolysis of at least one oxime IA functionalized polyolefin obtained in step 2) under inert conditions) can be considered in step 4), and in particular a Baeyer-Villiger reaction (also known as Baeyer-Villiger oxidation).

[0138] According to a first embodiment, step 4) preferably comprises a Baeyer-Villiger oxidation reaction. This reaction then yields a polyolefin functionalized with IC ester groups.

[0139] According to this embodiment, step 4) includes a step of contacting the polyolefin functionalized with carbonyl groups IB with a peracid, such as hydrogen peroxide, 3-chloroperbenzoic acid, peroxyacetic acid, or peroxytrifluoroacetic acid.

[0140] Preferably, this reaction is carried out in the presence of a solvent. Preferably, this reaction is carried out by heating the reaction mixture, for example to a temperature ranging from 50 °C to 190 °C, and typically from 70 °C to 110 °C.

[0141] Following the Baeyer-Villiger reaction, at least one polyolefin functionalized with IC ester groups can undergo a methanolysis reaction. Advantageously, according to this embodiment, the at least one polyolefin functionalized with IC ester groups is then contacted with methanol. Preferably, the methanol is introduced in excess. Preferably, this reaction is carried out in the presence of a solvent. Preferably, this reaction is carried out in an acidic medium: the reaction is then carried out in the presence of an acid, such as para-toluenesulfonic acid, for example.

[0142] According to a particular embodiment, step 2) includes, prior to a possible step 3) and / or 4), the purification of the functionalized polyolefin I obtained (polyolefin functionalized with oxime groups IA or polyolefin functionalized with carbonyl groups IB). This purification step can, for example, be carried out by precipitation of the functionalized polyolefin I. The precipitation can be followed by centrifugation(s) and / or iteration(s). It is clear that this purification step is optional, and that those skilled in the art can determine the benefit of performing such a step.

[0143] According to a first embodiment, steps 2) and 3) and / or 4) of the process according to the invention are carried out sequentially: the polyolefin functionalized with oxime groups IA (obtained in step 2)) and / or the polyolefin functionalized with carbonyl groups IB (obtained in step 2) or 3)) is isolated (after a possible purification step) and then engaged in step 3) or 4).

[0144] According to a second embodiment, steps 2) and 3) and / or 4 of the method according to the invention are carried out successively in the same extruder: the polyolefin functionalized with IA oxime groups (obtained in step 2)) and / or the polyolefin functionalized with carbonyl groups IB (obtained in step 2) or 3)) is not isolated (therefore no purification step) and is engaged in step 3) or 4) by adding the reagents into the extruder to carry out the reaction of step 3) or 4).

[0145] The process according to the invention makes it easy to obtain polyolefins (or molecules of smaller molecular weight) comprising a wide variety of functional groups. Furthermore, it is possible to use the known reactivity of oximes or carbonyls to obtain functional groups other than those described above without departing from the scope of the invention.

[0146] The invention also relates to the polyolefin functionalized with IA oxime groups obtained according to the process according to the invention detailed above.

[0147] The invention also relates to the polyolefin functionalized with carbonyl groups IB obtained according to the process according to the invention detailed above (under non-inert conditions at the end of step 2), or via the formation of at least one oxime functionalized polyolefin IA under inert conditions, followed by hydrolysis in acidic medium).

[0148] Examples

[0149] Example 1: Functionalization of HDPE under ambient air

[0150] Example 1.1: Carbonyl functionalized polyolefin IBl

[0151] A functionalization reaction by reactive extrusion under ambient air was carried out, as detailed below.

[0153] This reaction was carried out using a Brabender MetaStation 4 equipped with a Plastograph Type 50 mixer. The metering mixer was heated to 150 °C. The screw speed was set to 50 rpm and HDPE II-l (1 eq., M n = 15715 g / mol, D = 16.42; 30 g, 1.07 mol, marketed by Sigma Aldrich under the Reference 54799, with a melt index of 2.2 g / 10 min at 190°C and a mass of 2.16 kg, was sequentially added to the metering mixer for 5 minutes. The screw speed was then increased to 100 rpm. ε / δ-butyl nitrite III-9 (0.1 eq., 12.8 mL, 0.107 mol) was then added via syringe to the mixing zone for 5 minutes. The mixture was then extruded for a residence time of 2 hours at 150°C, with continuous monitoring of the viscosity change. The screw speed was then reduced to 0 rpm before opening the metering mixer. The resulting functionalized polymer IBl was collected with a spatula and cooled to room temperature (28 g, 93% conversion).

[0154] The polymer functionalized with carbonyl groups IBl was analyzed by X H RMN:

[0155] XH NMR (600 MHz, C2D2CI4, 110 °C) 5 2.46-2.43 (m), 1.85-1.72 (m), 1.50-1.29 (m), 1.01-0.94 (m).

[0156] The Specter X The H NMR obtained is shown in Figure 1.

[0157] The percentage of functionalization of the polymer functionalized with IBl carbonyl groups was determined by integrating characteristic signals from the NMR spectrum 1 H. Given the composition of the IBl polymer, the peaks between 0.8 and 2.0 ppm were incorporated into a total of 400 protons. The protons present in the alpha and alpha' positions of the incorporated carbonyl group, appearing between 2.43 and 2.46 ppm, were used to determine the molar percentage of carbonyl groups per repeating unit. Analyses of the functionalized IBl polymer thus obtained show that it is an HDPE functionalized with carbonyl groups, incorporating 0.6 mol% ketone groups.

[0158] The polymer functionalized with carbonyl groups obtained IBl was also analyzed by infrared spectroscopy.

[0159] IR (sec, ATR, cm' 1 ) 2914, 2846, 1554, 1471, 1461, 1367, 1262, 1100, 1026, 803, 730, 719.

[0160] The carbonyl-functionalized polymer obtained, IBl, was characterized by size exclusion chromatography, or gel permeation chromatography (140 °C, 1,3,5-trichlorobenzene). Size exclusion chromatography or Gel permeation chromatography (GPC) was performed using an Agilent PL-GPC120 (high temperature) instrument with refractive index detection, using polystyrene-in-trichlorobenzene (TCB) standard solutions with BHT at 140 °C. The instrument was equipped with a Plgel guard column and two Plgel 5 µm mixed-c columns. The results were compared with HDPE II-1 used as a reagent. The results are shown in Table 1 below.

[0161] Table 1

[0162] The degree of crystallinity was determined by differential scanning calorimetry (DSC), using the ratio between the enthalpy of fusion measured for the sample and the enthalpy of fusion of a 100% crystalline sample. This revealed that the degree of crystallinity of the HDPE II-1 used as a reagent is 63%, and that of the polyolefin functionalized with carbonyl groups IBl is 57%.

[0163] Example 1.2: Carbonyl functionalized polyolefin IB-2

[0164] Another functionalization reaction by reactive extrusion under ambient air was carried out, as detailed below.

[0166] This reaction was carried out using Thermo Scientific Minilab II HAAKE Rheomex CTW5 equipment. The dosing mixer was heated to 150 °C. The screw speed was set to 50 rpm. The HDPE II-l (M n= 15715 g / mol, D = 16.42; 4 g, 142.86 mmol, marketed by Sigma Aldrich under reference 54799, and having a melt index of 2.2 g / 10 min at 190°C and 2.16 kg) was added sequentially to the metering mixer for 5 minutes. The screw speed was then increased to 100 rpm. Then, te / t-butyl nitrite (1.7 mL, 14.286 mmol) was added using a syringe to the mixing zone for 5 minutes, and the mixture was extruded for a residence time of 2 hours at 150°C, with a Continuous monitoring of viscosity variation was performed. The screw speed was then reduced to 0 rpm before opening the metering mixer. The modified HDPE was then directly injected into a Mould Tensile Bar 557-2289 mold using a Thermo Scientific HAAKE MiniJET PRO device. Six test specimens of carbonyl functionalized polyolefin IB-2 were thus obtained (3.86 g, 96% conversion).

[0167] The polymer functionalized with carbonyl groups IB-2 was analyzed by X H RMN:

[0168] X H NMR (600 MHz, C2D2CI4, 110 °C) 5 2.46-2.43 (m), 1.85-1.75 (m), 1.50-1.29 (m), 1.01-0.94 (m).

[0169] The percentage of functionalization of the polymer functionalized with IB-2 carbonyl groups was determined by integrating characteristic signals from the NMR spectrum 1 H. Given the composition of the IB-2 polymer, the peaks between 0.8 and 2.0 ppm were incorporated into a total of 400 protons. The protons present in the alpha and alpha' positions of the incorporated carbonyl group, appearing between 2.43 and 2.46 ppm, are used to determine the molar percentage of carbonyl groups per repeating unit. Analyses of the functionalized IB-2 polymer thus obtained show that it is an HDPE functionalized with carbonyl groups, incorporating 0.05 mol% ketone groups.

[0170] The polymer functionalized with carbonyl functions obtained, IB-2, was also analyzed by infrared spectroscopy.

[0171] IR (sec, ATR, cm' 1 ) 3376, 2914, 2847, 2360, 2342, 1674, 1593, 1463, 1376, 1268, 1051, 972, 718, 445.

[0172] Example 2: Functionalization of HDPE under inert conditions

[0173] Example 2.1: Functionalized polyolefin oxime IAl

[0174] A functionalization reaction by reactive extrusion under an inert atmosphere was carried out, as detailed below.

[0176] This reaction was carried out using Thermo Scientific Minilab II HAAKE Rheomex CTW5 equipment. The dosing mixer was heated to 150 °C. The screw speed was set to 50 rpm. The system was purged with nitrogen for 5 minutes. HDPE II-1 (1 eq., Mn = 15715 g / mol, D = 16.42; 2.2 g, 78.6 mmol, marketed by Sigma Aldrich under reference 54799, and having a melt index of 2.2 g / 10 min at 190 °C and 2.16 kg) was added sequentially to the dosing mixer for 5 minutes. The screw speed was then increased to 100 rpm. Then, tert-butyl nitrite III-9 (0.1 eq., 0.95 mL, 7.86 mmol) was added via syringe to the mixing zone over a period of 5 minutes, and the mixture was extruded for a residence time of 2 hours at 150 °C, with continuous monitoring of the viscosity change. The entire procedure was thus carried out under a nitrogen flow.The screw speed was then reduced to 0 rpm before opening the dosing mixer. The functionalized IAl HDPE was then recovered using a spatula and cooled to room temperature (2.18 g, 99% conversion). NMR analysis showed that it was functionalized HDPE with oxime groups.

[0177] The polymer functionalized with IAl oxime groups was analyzed by X H RMN:

[0178] X H NMR (600 MHz, C2D2CI4, 110 °C) 5 2.46-2.14 (m), 1.85-1.75 (m), 1.50-1.29 (m), 1.01-0.94 (m).

[0179] The Specter X The H NMR obtained is shown in figure 2.

[0180] The percentage of oxime functional group incorporation in the IAl polymer was then determined by integrating the signals from the NMR spectrum 1H. Given the polymer composition, the peaks between 0.8 and 2.0 ppm were incorporated into a total of 400 protons. The protons present in the alpha and alpha' positions of the incorporated oxime group appear between 2.1 and 2.5 ppm and are used to determine the molar percentage of oxime group per repeat unit. It was thus determined that HDPE functionalized with oxime functions IAl contains 0.25 molar % of oxime functions.

[0181] The polymer functionalized with oxime functions obtained IAl was also analyzed by infrared spectroscopy.

[0182] IR (sec, ATR, cm' 1 ) 3376, 2914, 2847, 2360, 2342, 1674, 1593, 1463, 1376, 1268, 1051, 972, 718, 445.

[0183] The oxime-functionalized polymer obtained IAl was characterized by size-exclusion chromatography, or gel permeation chromatography (140 °C, 1,3,5-trichlorobenzene). Size-exclusion chromatography or gel permeation chromatography (GPC) was performed using an Agilent PL-GPC120 (high temperature) instrument with refractive index detection, using polystyrene-in-trichlorobenzene (TCB) standard solutions with BHT at 140 °C. The instrument was equipped with a Plgel guard column and two Plgel 5 pm mixed-c columns. The results were compared with HDPE II-I used as a reagent. The results are shown in Table 2 below.

[0184] Table 2

[0185] Example 2.2: IA-2 oxime functionalized polyolefin

[0186] Another functionalization reaction by reactive extrusion under an inert atmosphere was carried out, as detailed below.

[0187]

[0188] This reaction was carried out using a Thermo Scientific Minilab II HAAKE Rheomex CTW5. The dosing mixer was heated to 150 °C. The screw speed was set to 50 rpm. The system was purged with nitrogen for 5 minutes. The HDPE II-l (M n(15715 g / mol, D = 16.42; 3.12 g, 111.4 mmol, marketed by Sigma Aldrich under reference 54799, and having a melt index of 2.2 g / 10 min at 190°C and 2.16 kg) was added sequentially to the metering mixer for 5 minutes. The screw speed was then increased to 100 rpm. Next, te / t-butyl nitrite (1.5 mL, 11.14 mmol) was added using a syringe to the mixing zone for 5 minutes, and the mixture was extruded for a residence time of 2 hours at 150°C, with continuous monitoring of the viscosity change. The entire procedure was thus carried out under a nitrogen flow. The screw speed was then reduced to 0 rpm before opening the dosing mixer. The modified HDPE was then directly injected into a Mould Tensile Bar 557-2289 mold using a Thermo Scientific HAAKE MiniJET PRO device.Six test tubes of oxime IA-2 functionalized polyolefin were thus obtained (2.98 g, 96% conversion).

[0189] The polymer functionalized with IA-2 oxime groups was analyzed by X H RMN:

[0190] X H NMR (600 MHz, C2D2CI4, 110 °C) 5 2.46-2.14 (m), 1.85-1.75 (m), 1.50-1.29 (m), 1.01-0.94 (m).

[0191] The percentage of oxime functional group incorporation in the IA-2 polymer was then determined by integrating the signals from the NMR spectrum 1H. Given the polymer composition, the peaks between 0.8 and 2.0 ppm were incorporated into a total of 400 protons. The protons present in the alpha and alpha' positions of the incorporated oxime group appear between 2.1 and 2.5 ppm and are used to determine the molar percentage of oxime group per repeat unit. It was thus determined that HDPE functionalized with IA-2 oxime groups contains 0.1 molar percentage of oxime groups.

[0192] The polymer functionalized with oxime functions obtained IA-2 was also analyzed by infrared spectroscopy.

[0193] IR (sec, ATR, cm' 1 ) 3376, 2914, 2847, 2360, 2342, 1674, 1593, 1463, 1376, 1268, 1051, 972, 718, 445.

[0194] Polymers functionalized with IAl and IA-2 oxime groups can then be engaged in various reactions involving the oxime functions, as described in PCT / FR2024 / 050991 application.

[0195] Example 3: Baeyer-Villiger reaction on carbonyl functionalized HDPE IBl

[0196] A Baeyer-Villiger oxidation was then carried out on the HDPE functionalized with IBl carbonyl groups, as detailed below.

[0198] High-density polyethylene (HDPE) functionalized with IBl carbonyl groups, at an incorporation rate of 0.6 mol% (250 mg, 5.95 mmol), and 3-chloroperbenzoic acid (10.3 g, 59.5 mmol) were introduced into a round-bottom flask equipped with a magnetic stirrer and a condenser. The flask was then placed under vacuum. Three successive cycles of vacuum and argon purging were then performed. Under argon, chlorobenzene (50 mL) was added. The reaction flask was then heated to 100 °C for 30 minutes to obtain a homogeneous mixture. The reaction mixture was then maintained at 80 °C. The reaction was allowed to proceed under stirring for 24 hours before the mixture was cooled to room temperature. The homogeneous solution was then precipitated drop by drop into an excess of methanol (100 mL) under stirring.The medium was then transferred to two Falcon-type tubes to recover the polymer by centrifugation (three cycles). The recovered polymer was placed under high vacuum (< 1 mbar) overnight before being characterized (245 mg, 98% conversion).

[0199] The functionalized ICl ester HDPE obtained was characterized by X H RMN:

[0200] X H NMR (600 MHz, C2D2CI4, 110 °C) 5 (ppm) 5 4.17-4.15 (m), 2.45-2.43 (m), 2.39-2.36 (m), 1.74-1.71 (m), 1.51-1.29 (m), 1.02-0.97 (m).

[0201] The Specter X The H NMR obtained is shown in figure 3.

[0202] The functionalized ICl ester HDPE obtained was also analyzed by infrared spectroscopy.

[0203] IR (sec, ATR, cm' 1 ) 2914, 2847, 2630, 2342, 1674, 1593, 1463, 1376, 1268, 1051, 972, 718, 445.

[0204] The ester-functionalized HDPE ICl was characterized by size-exclusion chromatography, or gel permeation chromatography (140 °C, 1,3,5-trichlorobenzene). Size-exclusion chromatography, or gel permeation chromatography (GPC), was performed using an Agilent PL-GPC120 (high temperature) instrument with refractive index detection, using polystyrene-in-trichlorobenzene (TCB) standard solutions with BHT at 140 °C. The instrument was equipped with a Plgel guard column and two Plgel 5 µm mixed-c columns. The results were compared with HDPE II-I and with HDPE functionalized with carbonyl groups IBl, which was used as a reagent. The results are shown in Table 3 below.

[0205] Table 3

[0206] Example 4: Methanolyse reaction of functionalized ester HDPE IC-1

[0207] The functionalized HDPE ester ICl was then engaged in a methanolysis reaction, as detailed below.

[0208]

[0209] This reaction was carried out in a sealed tube. Functionalized HDPE ester I-Cl (26 mg, 0.45 mmol) and r-toluenesulfonic acid (0.13 mL, 0.9 mmol) were placed in the tube with a magnetic stirrer. Three successive cycles of vacuum and argon purging were then performed. Anhydrous methanol (3 mL) and toluene (8 mL) were then added under an argon flow. The reaction mixture was heated at 160 °C for 5 days and then cooled to room temperature. The homogeneous solution was then precipitated in excess methanol (10 mL). After 2 hours of stirring, the reaction medium was transferred into two Falcon-type tubes and the polymer mixture (HDPE functionalized Me ester IC-2 and HDPE functionalized hydroxyketone VI) was recovered by centrifugation (three cycles) before being placed under high vacuum (< 1 mbar) overnight, before being characterized (24 mg, 92% conversion).

[0210] The IC-2 + VI polymer mixture was analyzed by X H RMN:

[0211] X H NMR (600 MHz, C2D2CI4, 110 °C) 5 (ppm) 5 4.18-4.16 (m), 3.87-3.81 (m), 3.75 (s), 3.45-3.47 (m), 3.43 (s), 2.45-2.43 (m), 2.39-2.36 (m), 2.13-2.08(m), 1.74-1.70(m), 1.50-1.25(m), 1.02-0.97(m).

[0212] Spectrum analysis X H NMR made it possible to determine that the molar ratio of hydroxyketone VI functionalized HDPE to Me ester IC-2 functionalized HDPE is 1 / 3, taking into account the characteristic peaks of each of these products.

[0213] The IC-2 + VI polymer mixture was also analyzed by infrared spectroscopy:

[0214] IR (sec, ATR, cm' 1 ) 3376, 2914, 2847, 2630, 2342, 1674, 1593, 1463, 1376, 1268, 1051, 972, 718, 445.

[0215] The IC-2 + VI polymer blend was characterized by size exclusion chromatography, or gel permeation chromatography (140 °C, 1,3,5-trichlorobenzene). Size exclusion chromatography or gel permeation chromatography (GPC) was performed using an Agilent PL-GPC120 (high temperature) instrument with refractive index detection, using polystyrene-in-trichlorobenzene (TCB) standard solutions with BHT at 140 °C. The instrument was equipped with a Plgel guard column and two Plgel 5 pm mixed-c columns. The results were compared with HDPE II-1, HDPE functionalized with groups carbonyls IBl, and the functionalized HDPE ester ICl were used as reagents. The results are shown in Table 4 below.

[0216] Table 4

[0217] Example 5: Functionalization of LLDPE under ambient air

[0218] A functionalization reaction by reactive extrusion under ambient air was carried out, as detailed below.

[0219] H-2 HI-9 IB-3

[0220] This reaction was carried out using a Thermo Scientific Minilab II HAAKE Rheomex CTW5. The dosing mixer was heated to 150 °C. The screw speed was set to 50 rpm. LLDPE II-2 (3.2 g, 78.6 mmol, 1 eq., marketed by Sigma Aldrich under reference number 428043) was added sequentially to the dosing mixer for 5 minutes. The screw speed was then increased to 100 rpm. Next, te / t-butyl nitrite (0.94 mL, 7.86 mmol, 0.1 eq.) was added using a syringe to the mixing zone for 5 minutes, and the mixture was extruded for a residence time of 1 hour at 150 °C. The resulting functionalized polymer IB-3 was recovered and cooled to room temperature (2.18 g, 99% conversion).

[0221] The polymer functionalized with carbonyl groups IB-3 was analyzed by X H NMR:

[0222] X H NMR (600 MHz, C2D2CI4, 110°C) 5 2.27 (m), 1.68-1.66 (m), 1.50-1.29 (m), 1.01-0.94 (m).

[0223] The Specter X The H NMR obtained is shown in figure 4.

[0224] The percentage of functionalization of the polymer functionalized with IB-3 carbonyl groups was determined by integrating characteristic signals from the spectrum X H NMR. Analyses of the functionalized polymer IB-3 thus obtained show that it is an LLDPE functionalized with carbonyl functions, incorporating 0.6 mol% of carbonyl functions per repeating unit.

[0225] The polymer functionalized with carbonyl groups obtained IB-3 was also analyzed by infrared spectroscopy.

[0226] IR (sec, ATR, cm' 1) 2916, 2844, 1614, 1461, 1369, 719.

[0227] The carbonyl-functionalized polymer IB-3 was characterized by size-exclusion chromatography (140 °C, 1,3,5-trichlorobenzene). Size-exclusion chromatography was performed using an Agilent PL-GPC120 high-temperature instrument with refractive index detection, using polystyrene-in-trichlorobenzene (TCB) standard solutions with BHT at 140 °C. The instrument was equipped with a Plgel guard column and two Plgel 5 µm mixed-c columns. The results were compared with LLDPE 11-12 used as a reagent. The results are shown in Table 5 below.

[0228] Table 5

[0229] The degree of crystallinity was determined by differential scanning calorimetry (DSC), using the ratio between the enthalpy of fusion measured for the sample and the enthalpy of fusion of a 100% crystalline sample. This revealed that the degree of crystallinity of LLDPE II-2 used as a reagent is 36%, and that of the polyolefin functionalized with carbonyl groups IB-3 is 31%.

[0230] Example 6: Functionalization of HDPE waste under ambient air

[0231] A functionalization reaction by reactive extrusion under ambient air was carried out, as detailed below. The HDPE II-3 waste used is an empty HDPE bottle, initially containing dichloromethane marketed by VWR, which was previously ground into pieces (5 mm x 5 mm x 1 mm).

[0232] This reaction was performed using Thermo Scientific Minilab II HAAKE Rheomex CTW5 equipment. The dosing mixer was heated to 150 °C. The screw speed was set to 50 rpm. HDPE II-3 waste (3.2 g, 78.6 mmol, 1 eq.) was added sequentially to the dosing mixer for 5 minutes. The screw speed was then increased to 100 rpm. Next, te / t-butyl nitrite (0.94 mL, 7.86 mmol, 0.1 eq.) was added using a syringe to the mixing zone for 5 minutes, and the mixture was extruded for a residence time of 1 hour at 150 °C. The resulting functionalized polymer, IB-4, was recovered and cooled to room temperature (2.18 g, 99% conversion).

[0233] The carbonyl-functionalized polymer IB-4 was analyzed by X H RMN:

[0234] X H NMR (600 MHz, C2D2CI4, 110°C) 5 2.46-2.43 (m), 1.68-1.66 (m), 1.50-1.29 (m), 1.02-0.99 (m).

[0235] The Specter X The H NMR obtained is shown in figure 5.

[0236] The percentage of functionalization of the polymer functionalized with IB-4 carbonyl groups was determined by integrating characteristic signals from the spectrum X H NMR. Analyses of the functionalized IB-4 polymer thus obtained show that it is an HDPE functionalized with carbonyl functions, incorporating 0.6 mol% of carbonyl functions per repeating unit.

[0237] The polymer functionalized with carbonyl groups obtained IB-4 was also analyzed by infrared spectroscopy.

[0238] IR (sec, ATR, cm' 1 ) 2916, 2844, 1718, 1676, 1465, 1379, 1259, 1085, 1012, 717.

[0239] The carbonyl-functionalized polymer IB-4 was characterized by size-exclusion chromatography (140 °C, 1,3,5-trichlorobenzene). Size-exclusion chromatography was performed using an Agilent PL-GPC120 high-temperature instrument with refractive index detection, using polystyrene-in-trichlorobenzene (TCB) standard solutions with BHT at 140 °C. The instrument was equipped with a Plgel guard column and two Plgel 5 µm mixed-c columns. The results are shown in Table 6 below.

[0240] Table 6

[0241] The degree of crystallinity was determined by differential scanning calorimetry (DSC), using the ratio between the enthalpy of fusion measured for the sample and the enthalpy of fusion of a 100% crystalline sample. This revealed that the degree of crystallinity of HDPE II-3 used as a reagent is 55%, and that of the polyolefin functionalized with carbonyl groups IB-4 is also 55%.

[0242] Example 7: Functionalization of LDPE waste under ambient air

[0243] A functionalization reaction by reactive extrusion under ambient air was carried out, as detailed below. The LDPE II-4 waste used is a flexible plastic pool packaging bag, previously cut into pieces (1 cm x 2 cm x 0.1 cm).

[0244] This reaction was carried out using Thermo Scientific Minilab II HAAKE Rheomex CTW5 equipment. The dosing mixer was heated to 150 °C. The screw speed was set to 50 rpm. The LDPE II-4 waste (3.2 g, 78.6 mmol, 1 eq.) was The mixture was added sequentially to the metering mixer for 5 minutes. The screw speed was then increased to 100 rpm. Next, te / t-butyl nitrite (0.94 mL, 7.86 mmol, 0.1 eq.) was added using a syringe to the mixing zone for 5 minutes, and the mixture was extruded for a residence time of 1 hour at 150 °C. The resulting functionalized polymer, IB-5, was recovered and cooled to room temperature (2.18 g, 99% conversion).

[0245] The carbonyl-functionalized polymer IB-5 was analyzed by X H RMN:

[0246] X H NMR (600 MHz, C2D2CI4, 110°C) 5 2.46-2.42 (m), 1.51-1.24 (m), 1.00-0.94 (m).

[0247] The Specter X The H NMR obtained is shown in figure 6.

[0248] The percentage of functionalization of the polymer functionalized with IB-5 carbonyl groups was determined by integrating characteristic signals from the spectrum X H NMR. Analyses of the functionalized IB-5 polymer thus obtained show that it is an LDPE functionalized with carbonyl functions, incorporating 0.6 mol% of carbonyl functions per repeating unit.

[0249] The polymer functionalized with carbonyl groups obtained IB-5 was also analyzed by infrared spectroscopy.

[0250] IR (sec, ATR, cm' 1 ) 2916, 2846, 2364, 1722, 1629, 1461, 1373, 1257, 1110, 1012, 721.

[0251] The carbonyl-functionalized polymer IB-5 was characterized by size-exclusion chromatography (140 °C, 1,3,5-trichlorobenzene). Size-exclusion chromatography was performed using an Agilent PL-GPC120 high-temperature instrument with refractive index detection, using polystyrene-in-trichlorobenzene (TCB) standard solutions with BHT at 140 °C. The instrument was equipped with a Plgel guard column and two Plgel 5 pm mixed-c columns. The results are shown in Table 7 below.

[0252] Table 7

[0253] The limited crystallization rate was determined by differential scanning calorimetry (DSC) as the ratio between the enthalpy of fusion measured for the sample and the enthalpy of fusion of a 100% crystalline sample. This revealed that the crystallinity of the HDPE II-3 used as a reagent is 39%, and that of the polyolefin functionalized with carbonyl groups IB-5 is 36%.

[0254] Example 8: Mechanical tests, contact angle measurements, and thermogravimetric analyses

[0255] A study of the impact of incorporating oxime or carbonyl groups by reactive extrusion on the mechanical properties of HDPE was carried out. Three extrusion reactions were performed for this purpose, with direct shaping of the specimens using an injector at the outlet (Haake MiniJet PRO).

[0256] An extrusion for each of the following polyolefins was first carried out: HDPE II-1, LLDPE II-2, HDPE II-3, LDPE II-4, carbonyl functionalized polyolefin IB-2, oxime functionalized polyolefin IA-2, carbonyl functionalized polyolefin IB-3, carbonyl functionalized polyolefin IB-4, and carbonyl functionalized polyolefin IB-5, as detailed above.

[0257] The test specimens were produced by injection molding using a Thermo Scientific HAAKE MiniJet Pro device in a Mold Tensile Bar ISO527-2-1BA mold. The injector temperature was 160°C, and the mold temperature was 90°C. An injection pressure of 600 bar was used, with an injection time of 1 minute. The specimens were cured for 48 hours before tensile testing.

[0258] Tensile measurements were performed using a Qtest / 25 Elite Controller device with a tensile speed of 10 mm / min. Five tensile strength measurements were performed on specimens from the same reaction in order to Verify the accuracy of the measurements. The data reported in Table 8 below is an average of these five measurements.

[0259] Table 8

[0260] Contact angle measurements were also performed on these materials and are presented in Table 9. The contact angles were determined using a Kruss DSA100 contact angle measurement system at room temperature. For this purpose, a 2-microliter water droplet was placed on the samples. A charge-coupled device (CCD) camera was used to capture images of the water droplets for contact angle determination. Five successive contact angle measurements were taken on each sample to confirm the accuracy of the measurements.

[0261] Table 9

[0262] A decrease in contact angles after reactive extrusion reaction is observed, indicating that the incorporation of oxime or ketone functions reduces the hydrophobicity of HDPE.

[0263] A thermogravimetric analysis of each of the different exemplified polymers was also carried out using a TA Instruments G500 machine, from ambient temperature to 600 °C with a ramp rate of 10 °C / min, under a nitrogen atmosphere and with a platinum capsule. The results are reported in Table 10 below, T d 0.5% representing the initial decomposition temperature measured for 5% mass loss.

[0264] Table 10

Claims

1. DEMANDS 1. A process for preparing at least one functionalized polyolefin (I) comprising the following steps: 1) have at least one polyolefin of formula (II): with : - Rl representing a methyl, ethyl or n-butyl group, - R2 representing H, CH3 or OH, - n representing an integer ranging from 0 to 100000, - m representing an integer ranging from 0 to 100000, and - n + m + 0, and 2) react at least one polyolefin (II) with at least one nitrosating agent (III) in an extruder.

2. A method according to claim 1, wherein at least one nitrosating agent (III) is selected from: (III-C) and their mixtures, with: - R4 and R5 being identical or different and independently representing a group chosen from (Cl-C6)alkyl, N[(Cl-C6)alkyl]3, CO[(Cl-C6)alkyl], SO2Ph, CO-Ph-CF3, - or R4 and R5 together forming a (C5-C10) cycloalkylene group possibly substituted by one or more (C1-C6) linear or branched alkyl groups, or a -SO2-Ph-C(CH3)2- group, or a -CO-Ph-CO- group, - R6 representing a phthalimide group or a linear or branched (Cl-C6)alkyl group, and - R7 representing an aromatic or heteroaromatic group possibly perfluorinated.

3. A method according to claim 1 or 2, wherein at least one nitrosating agent is selected from: mixtures.

4. A method according to any one of the preceding claims, wherein the molar ratio of nitrosating agent(s) (III) / repeating units of polyolefin(s) (II) ranges from 0.01 to 2, preferably from 0.1 to 0.

5.

5. A method according to any one of the preceding claims wherein at least one polyolefin (II) is selected from polyethylene, polypropylene optionally hydroxylated at the terminal position, an ethylene-propylene copolymer optionally hydroxylated at the terminal position, and mixtures thereof.

6. A method according to any one of the preceding claims, wherein, in step 2), the temperature within the extruder is greater than or equal to the melting temperature of at least one polyolefin (II), and less than the degradation temperature of at least one nitrosating agent (III).

7. A process according to any one of the preceding claims, wherein step 2) is carried out under inert conditions, in order to obtain at least one polyolefin functionalized with oxime groups (IA).

8. A method according to the preceding claim comprising further a step 3) subsequent to step 2), said step 3) consisting of reacting the oxime groups present in at least one polyolefin functionalized with oxime groups (IA).

9. A method according to the preceding claim, wherein step 3) comprises the reaction of at least one acid chloride with the oxime groups of at least one polyolefin functionalized with oxime groups (IA).

10. A method according to claim 8, wherein step 3) comprises a Beckmann rearrangement.

11. A method according to the preceding claim, wherein step 3) comprises an acid hydrolysis reaction, subsequent to the Beckmann rearrangement.

12. A method according to claim 8, wherein step 3) comprises the reduction of oxime groups of at least one polyolefin functionalized with (I-A) oxime groups.

13. A process according to claim 8, wherein step 3) comprises the reaction of at least one isocyanate with the oxime groups of at least one polyolefin functionalized with oxime groups (IA).

14. A method according to claim 8, wherein step 3) comprises a polymer chain grafting reaction, such as polyethylene glycol or polycaprolactone chains.

15. A method according to claim 8, wherein step 3) comprises an acid hydrolysis reaction of at least one polyolefin functionalized with oxime groups (IA), in order to obtain at least one polyolefin functionalized with carbonyl groups (IB).

16. A process according to any one of claims 1 to 6, wherein step 2) is carried out in the presence of air, in order to obtain at least one polyolefin functionalized with carbonyl groups (IB).

17. A process according to claim 15 or 16, comprising a step 4) subsequent to step 2) and subsequent to step 3) when the latter is performed, consisting of reacting the carbonyl groups present in at least one polyolefin functionalized with carbonyl groups (IB).

18. A process according to the preceding claim, wherein step 4) comprises a Baeyer-Vil liger reaction.

19. A process according to the preceding claim, wherein the Baeyer-Villiger reaction is followed by a methanolysis.

20. Polyolefin functionalized with oxime groups (IA) obtained according to the process according to claim 7.

21. Polyolefin functionalized with carbonyl groups (IB) obtained according to the process according to claim 15 or 16.

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