Method for functionalizing polyolefins via the introduction of an oxime function

Abstract

Method for functionalizing polyolefins via the introduction of an oxime function The invention relates to a method for functionalizing at least one polyolefin comprising functionalizing the polyolefin with oxime groups, followed by a reaction of the introduced oxime groups. Figure for abstract: Fig. 1

Description

Title of the invention: Method for functionalizing polyolefins via the introduction of an oxime function Technical field

[0001] The invention relates to a method for functionalizing polyolefins via the introduction of oxime groups. Prior art

[0002] Currently, plastic waste pollution is constantly increasing and has therefore become a major problem. Indeed, this source of pollution has harmful effects in waterways, seas and oceans, and on marine animals.

[0003] About a third of the plastics produced are polyolefins. These plastic wastes are generally made from polymers designed to be strong, both mechanically and chemically. Recycling and recovering them is therefore difficult.

[0004] Nowadays, plastic waste is often either landfilled, incinerated, or mechanically recycled. Landfilling carries the risk of dispersing the lightest plastics due to wind. Incineration has the disadvantage of releasing toxic products, including greenhouse gases. For example, HCl is released when PVC burns. It is therefore necessary to find alternatives to recycle plastic waste in a closed loop or to "upcycle" it, i.e. to recover it into smaller molecules with added value.

[0005] Currently, plastic recycling is mainly mechanical: the polymer is extruded in order to be reused. The disadvantage associated with such a process is that the polymer degrades over repeated extrusions, which leads in particular to a reduction in its mechanical properties. Consequently, the polymer can no longer be reused after a certain number of extrusions. In addition, soiled plastics are very difficult to recycle in this way.

[0006] Another solution is currently being researched: the chemical or enzymatic degradation of polymers.

[0007] As for the enzymatic degradation of polymers, we can notably cite the enzymatic degradation of PET (Nature, vol. 580 (2020), 216-219). This method allows, in 10 h and thanks to enzymes, to depolymerize at least 90% of the PET into monomers which can then be reused to synthesize PET again for example. If this solution seems effective, it is only applicable to PET, and not to polyolefins which only contain less hydrocarbon chains reactive than the ester functions of PET.

[0008] As for chemical degradation, a widely studied route is the introduction of polar groups, and in particular ester groups via a prior oxidation of the parent polymer introducing carbonyl or hydroxyl functions, followed by a Baeyer-Villiger reaction. However, the preliminary step is not well controlled because it is not selective.

[0009] Another method has been reported by Conk et al. (Science, 377, 1561-1566, 2022), which describes the production of propylene by partial dehydrogenation of polyethylene and tandem ethanolysis-isomerization. This method is particularly interesting since it allows to obtain highly recoverable products. However, this method involves the use of expensive catalysts: iridium or platinum and zinc complex for the dehydrogenation of polyethylene, and second generation Hoveyda-Grubbs metathesis catalyst and [PdP(t-Bu)3(p-Br)]2 for the isomerization. In addition, heating and high pressure are required.

[0010] The Applicant therefore sought an easy-to-implement alternative method for the recycling and recovery of polyolefins. The Applicant was particularly interested in the functionalization of these polyolefins with oxime groups, with a view to using the particular reactivity of these oxime functions to recover these polyolefins. Indeed, as explained in particular in the document Ry-kaczewski et al. (Nature Synthesis, 2022, vol. 1, 24-36), the oxime functions have a reactivity towards transition metals and photocatalysis such that they constitute reagents of choice for the synthesis of nitrogen heterocycles, amino alcohols and amines in particular.

[0011] In order to introduce oxime functions into polyolefins, the Applicant sought a process that is easy to implement and effective. Advantageously, the process is reproducible. Advantageously, the process can be used with various polyolefins, and in particular different grades of polyethylene, polypropylene, and hydroxypolymethylene.

[0012] The Applicant was particularly interested in the photochemical transformation allowing the introduction of an oxime function on an alkane. This reaction has been studied in particular for the synthesis of caprolactam which is a precursor of Nylon-6. For example, the Toray process (US 3,090,739) involves the preparation of cyclohexanone oxime by introducing an oxime unit into cyclohexane photochemically using NOC1 and HCl under UV (mercury vapor lamp). The cyclohexanone oxime is then transformed into caprolactam under acidic conditions. This process has the disadvantage of using NOC1 and HCl which are corrosive. In order to overcome this problem, the use of less corrosive alternative reagents has been studied. In particular, it has been reported, in particular in the document Wysocki et al. (ChemPhotoChem, 2018, 2, 22-26), the photochemical transformation of cyclohexane to cyclohexanone oxime using tert-butyl nitrite (t-BuONO) and UV irradiation. The best yields were obtained using 0.1 equivalents of t-BuONO and 0.8 equivalents of t-BuOH for one equivalent of cyclohexane, and a UV lamp at 365 nm, at a temperature of 50 °C.

[0013] However, no studies have been reported on the introduction of oxime functions into polyolefins.

[0014] Furthermore, the Applicant is not aware of any documents reporting polyolefins functionalized with oxime groups undergoing post-functionalization, hydrolysis, reduction or Beckmann rearrangement for example. Statement of the invention

[0015] Polyolefins have a different reactivity from those of alkanes, in particular in terms of viscosity, crystallinity, solubility, and accessibility to the reaction site. The Applicant has therefore undertaken research work to determine the operating conditions allowing the introduction of oxime units on different polyolefins. Advantageously, the polyolefins functionalized with oximes thus obtained can then be post-functionalized, undergo hydrolysis or reduction, or a Beckmann rearrangement for example. The method according to the invention then makes it possible to enhance the value of the polyolefins thus functionalized which show properties different from the parent polymers.

[0016] The invention firstly relates to a method for functionalizing polyolefins, and thus enhancing their value. The method according to the invention comprises the following steps: 1) have at least one polyolefin of formula I: 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 + mt 0, 2) functionalizing at least one polyolefin I with oxime groups, in order to obtain at least one polyolefin functionalized with oxime groups II, 3) reacting the oxime groups present in the at least one functional polyolefin- nationalized with oxime groups II.

[0017] The method according to the invention has the advantage of being simple to implement.

[0018] The method according to the invention also has the advantage of allowing the obtaining small molecules and polymers of varying sizes (chain length and functional groups introduced), depending on the intended use. Indeed, the first step consists of introducing oxime units. This first step has the advantage of generating few by-products, which are easily removed by precipitation and filtration. Then, during a second step, these oxime groups can be hydrolyzed, reduced, post-functionalized or undergo a Beckmann rearrangement. Thus, from a polyolefin, it is possible to obtain a very wide range of molecules and polymers, with very varied functional groups such as amide, amine, carboxylic acid functions, etc.

[0019] The method according to the invention has the advantage of being effective on polyolefins of various structures. In addition, it has been demonstrated that the method according to the invention is effective not only on polyolefins but also on plastic waste containing them.

[0020] The method according to the invention may have one or other of the following characteristics, or a combination of these characteristics: - step 2) comprises the reaction, under irradiation at a wavelength belonging to the range from 300 nm to 450 nm, of at least one polyolefin of formula I and at least one nitrosating agent III; - the nitrosating agent III is of formula Ill-a, Ill-b or IILc below: R4 R5(III-a), O. (ni-b), S (IILc), N Rg NO FY NO NO with : - R4 and R5 being identical or different and representing independently of one another a group chosen from (C1-C6) alkyl, N[(C1-C6) alkyl]3, CO[(C1-C6) alkyl], SO2Ph, CO-Ph-CF3, - or R4 and R5 together forming a (C5-C10) cycloalkyl 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, - R6 representing a phthalimide group or a linear or branched (C1-C6) alkyl group, - R7 representing an aromatic or heteroaromatic group possibly perfluorinated; - the at least one nitrosating agent is chosen from: - the molar ratio of nitrosating agent(s) III / polyolefin repeating unit(s) I ranges from 0.01 to 2, preferably from 0.1 to 0.5; - the reaction in step 2) is carried out in the presence of t-BuOH; - the molar ratio of nitrosating agent(s) III / t-BuOH ranges from 0.1 to 0.01, preferably 0.1; - the reaction is carried out at a temperature of up to 130°C; - the at least one polyolefin I is chosen from polyethylene and polypropylene optionally hydroxylated in the terminal position, or an ethylene-propylene copolymer optionally hydroxylated in the terminal position; - step 3) comprises the reaction of at least one acid chloride with the oxime groups of the polyolefin functionalized with oxime groups II; - step 3) includes a Beckmann rearrangement; - step 3) comprises a hydrolysis reaction in an acid medium, subsequent to the Beckmann rearrangement; - step 3) comprises the reduction of the oxime groups of the polyolefin functionalized with oxime groups II; - step 3) comprises a hydrolysis reaction in an acid medium; - step 3) comprises the reaction of at least one isocyanate with the oxime groups of the polyolefin functionalized with oxime groups II. Brief description of the drawings

[0021] [Fig.l] [Fig.l] is the 'H NMR spectrum of oxime functionalized HDPE 11-5.

[0022] [Fig.2] [Fig.2] is the HMBC NMR spectrum of oxime 11-5 functionalized HDPE.

[0023] [Fig.3] [Fig.3] is the 'H NMR spectrum of the polymer functionalized with oxime groups 11-6.

[0024] [Fig.4] [Fig.4] is the 'H NMR spectrum of the polymer functionalized with oxime groups 11-7.

[0025] [Fig.5] [Fig.5] is the 'H and 19F NMR spectrum of the functionalized polymer VI-1.

[0026] [Fig.6] [Fig.6] is the 'H and 19F NMR spectrum of the functionalized polymer VL2.

[0027] [Fig.7] [Fig.7] is the 'H NMR spectrum of the functionalized polymer VII-1.

[0028] [Fig.8] [Fig.8] is the 'H NMR spectrum of the functionalized polymer VIII-1.

[0029] [Fig.9] [Fig.9] is the 'H NMR spectrum after nitrosation reaction on a sample of an HDPE bottle.

[0030] [Fig. 10] [Fig. 10] is the 'H NMR spectrum after nitrosation reaction on a sample of an LDPE plastic bag. Description of the embodiments

[0031] The invention relates to a method for functionalizing at least one polyolefin I comprising the following steps:

[0032] 1) have at least one polyolefin of formula I:

[0033] [Chem.l] (I) Ri

[0034] 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 + mt 0.

[0035] 2) functionalize the at least one polyolefin I with oxime groups, in order to obtain at least one polyolefin functionalized with oxime groups II,

[0036] 3) reacting the oxime groups present in the ... rationalized with IL oxime groups

[0037] In the context of the invention, "at least one polyolefin I" means exactly one polyolefin I or a mixture of several polyolefins each of formula I. In the following and unless otherwise specified, reference is made to "the polyolefin" instead of "the at least one polyolefin" for reasons of simplicity, but it is understood that one or more polyolefins I may be used in the context of the invention.

[0038] In the context of the invention, the term "functionalizing a polymer" means introducing at least one chemical function into the polymer, either into the polymer chain (i.e. the function interrupts the polymer chain), or as as a substituent on the polymer chain. The chemical functions can, for example, be amine, hydroxylamine, amide functions, etc., as will be detailed later.

[0039] In the context of the invention, “functionalizing a polyolefin with oxime groups”, “introducing oxime groups onto a polyolefin” and “nitrosylating a polyolefin” are synonymous, and designate the introduction of an oxime group (=N-OH) onto the polyolefin, onto the main chain and / or onto the branched chain(s) if they are present.

[0040] In the context of the invention, the term "polyolefin functionalized with oxime groups" or "nitrosylated polyolefin" means a polyolefin comprising at least one oxime substituent. When the polyolefin functionalized with oxime groups comprises several oxime groups or substituents, these groups can be distributed regularly or statistically on said polyolefin functionalized by oxime groups. According to a particular embodiment, the distribution of the oxime groups can be oriented thanks to the prior introduction of functional groups which make it possible to orient the selectivity during the reaction of introduction of the oxime groups.

[0041] By “oxime group” is meant an =N-OH group.

[0042] According to a preferred embodiment, the polyolefin of formula I is such that RI represents CH3, R2 represents H, CH3 or OH, n represents an integer ranging from 0 to 100000, and m represents an integer ranging from 0 to 100000, it being understood that ne and m are not both equal to 0. In other words, according to this embodiment, the polyolefin I is either a homopolymer of ethylene or propylene, optionally hydroxylated in the terminal position, or a copolymer of ethylene and / or propylene, optionally hydroxylated in the terminal position.

[0043] According to a first embodiment, the polyolefin I is a homopolymer. In other words, according to this embodiment, the polyolefin I is either polyethylene (i.e. n=0 and m^0), or polypropylene or polybutylene or polyhexylene optionally hydroxylated in the terminal position (i.e. m=0 and n^0, and RI represents respectively Me, Et or Bu).

[0044] According to this first embodiment, the polyethylene may be low density polyethylene or high density polyethylene.

[0045] 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 at high temperatures (typically from 200 °C to 300 °C) (see documents Aggarwal et al., Chem. Rev. 1957, 57, 4, 665-742, and Jubinville et al., Sustain. Mater. Technol. 25, 2020, eOO188). This type of polymerization generates numerous branches, both long and short. These are due to inter and intra chain transfers. tramolecular, respectively, during polymerization. The density of LDPE ranges from 0.915 to 0.933 g.cm3.

[0046] Within the framework of the invention, the density of the different polymers can be determined according to the ISO 1183-3:1999 standard.

[0047] In the context of the invention, "high density polyethylene" or HDPE can be synthesized at lower pressure (typically from 1 atm to 300 atm), for example in the presence of a Ziegler-Natta metal catalyst (see documents Aggarwal et al., Chem. Rev. 1957, 57, 4, 665-742, and Jubinville et al., Sustain. Mater. Technol. 25, 2020, eOO188). This process makes it possible to obtain a linear polyethylene which contains little or no branching. The density of HDPE ranges from 0.93 to 0.97 g.cm3.

[0048] High-density polyethylene (HDPE) and low-density polyethylene (LDPE) differ due to their degree of branching, and their level of crystallinity. High-density polyethylene is more crystalline than low-density polyethylene.

[0049] 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.

[0050] According to a second embodiment, the polyolefin I is a copolymer. In other words, the polyolefin is such that n^0 and m^0. The copolymer may be a block or random copolymer.

[0051] Preferably according to this embodiment, the polyolefin is either a copolymer of ethylene and propylene, optionally hydroxylated, or a linear low density polyethylene (LLDPE).

[0052] In the context of the invention, a “linear low density polyethylene” or LLDPE is a copolymer of ethylene with an olefin chosen from propylene, butylene, pentylene, hexylene and octylene. Such a polymer can be obtained by the Ziegler-Natta route (see Aggarwal et al., Chem. Rev. 1957, 57, 4, 665-742, and Jubinville et al., Sustain. Mater. Technol. 25, 2020, eOO188). The density of LLDPE ranges from 0.92 to 0.94 g.cm3.

[0053] According to an advantageous embodiment of the invention, the crystallinity rate (mass or volume) of the polyolefin I ranges from 40% to 95%, preferably from 40% to 80%. The crystallinity rate is a measure of the proportion of crystalline material in the sample studied. In the context of the invention, the crystallinity rate can be determined, for example, by differential scanning calorimetry (DSC), by the ratio between the enthalpy of fusion measured for the sample considered and the enthalpy of fusion of the 100% crystalline sample.

[0054] According to an advantageous embodiment of the invention, the melting temperature of polyolefin I ranges from 120°C to 140°C. In the context of the invention, the melting temperature of polyolefin I 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 of the peak of the thermal phenomenon corresponding to the melting.

[0055] The second step of the method according to the invention consists of introducing at least one oxime function onto the polyolefin I to obtain a polyolefin functionalized with oxime groups II. These oxime functions can be distributed regularly or statistically on the polymer chain.

[0056] Several methods can be envisaged for introducing oxime functions onto polyolefin I (step 2). Hereinafter, a preferred method is described and called "method of the invention" but it is understood that another method could be used without departing from the scope of the invention. The method according to the invention makes it possible to easily introduce oxime functions and has the advantage of generating few by-products, which can be easily removed by precipitation and filtration or any other purification method. The method according to the invention makes it possible to obtain polyolefins functionalized with oxime functions II with a molar percentage of incorporation of oxime functions in polyolefin I ranging from 0.5 to 10%. The molar percentage of incorporation of oxime functions is the molar percentage of oxime functions per repeating unit of polyolefin I, as detailed below. It can be determined by 'H NMR.

[0057] Preferably, step 2) of the method according to the invention (or “process according to the invention”) comprises the reaction, under irradiation at a wavelength belonging to the range from 300 nm to 450 nm, of the polyolefin I and at least one nitrosation agent III.

[0058] The method according to the invention is carried out under UV or near-visible irradiation, preferably under UV irradiation. According to a preferred embodiment, the reaction is carried out under irradiation at a wavelength ranging from 350 nm to 430 nm, and preferably at a wavelength ranging from 365 nm to 405 nm. Advantageously, the method is carried out at a wavelength corresponding to an absorption line of the nitrosating agent. According to a first particular embodiment of the invention, the reaction is carried out at a wavelength ranging from 365 nm to 370 nm. According to a second particular embodiment of the invention, the reaction is carried out at 405 nm. Preferably, the reaction is carried out at a wavelength of 365 nm.

[0059] Several devices (typically lamps) are known to those skilled in the art and are commercially available for carrying out reactions at these wavelengths. The number and arrangement of these devices around the reactor may vary, according to techniques usual for those skilled in the art. Thus, a single device may be used, or several arranged (typically two or three) around the reactor, or even a series of devices distributed around the entire perimeter of the reactor.

[0060] The nitrosating agent III that can be used is of formula:

[0061] [Chem. 2] R3--NO (III),

[0062] with R3 representing a group comprising an N, O or S atom linked to the NO group.

[0063] In other words, the nitrosating agent is a compound that allows the release of the NO* radical under the reaction conditions.

[0064] Advantageously, the nitrosating agent III is of the following formula III-a, III-b or III-c:

[0065] [Chem. 3] R4K (111^ N NO

[0066] with R4 and R5 being identical or different and representing independently of one another 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) cycloalkyl 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 representing, independently of one another, 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) cycloalkyl 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,

[0067] [Chem. 4] O (IH-b) Rp NO

[0068] 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,

[0069] [Chem. 5] (IILc) R< NO

[0070] with R7 representing an optionally perfluorinated aromatic or heteroaromatic group, preferably R7 representing a perfluorinated aromatic or heteroaromatic group, more preferably R7 representing a perfluorinated heteroaromatic group.

[0071] Preferably, the at least one nitrosation agent III is chosen from:

[0072] [Chem. 6]

[0075] [Chem. 9]

[0076]

[0077]

[0078] [Chem. 12]

[0079] [Chem. 13]

[0080] [Chem. 14]

[0081] According to a preferred embodiment, only one nitrosating agent is used.

[0082] According to a preferred embodiment, the nitrosating agent III is tert-butylnitrite III-9.

[0083] Preferably, the molar ratio of nitrosating agent III / repeating unit(s) of polyolefin(s) I ranges from 0.01 to 2, preferably 0.1 to 0.5.

[0084] By "repeating unit" or "repeating unit" of a polymer is meant the smallest constituent unit whose repetition describes the polymer. In the case of a copolymer, this is made up of several distinct repeating units.

[0085] In the context of the invention, the number of moles of repeating units of a polymer is estimated using the method detailed in the document 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 of the repeating units (if copolymer). For the particular case of functionalized polyolefins with oxime groups II, it is considered, for the determination of the number of moles of repeating units, that all the repeating units are functionalized with oxime groups: the number of moles of repeating units of a polyolefin functionalized with oxime groups II is then equal to the ratio between the mass of polyolefin functionalized with oxime groups II and the molar mass of the repeating units including an oxime group.

[0086] According to a preferred embodiment of the invention, the process according to the invention is carried out in the presence of t-BuOH. According to this embodiment, the molar ratio of nitrosation agent(s) III / t-BuOH advantageously ranges from 0.1 to 0.01, and preferably is 0.1. According to this embodiment, the molar ratio of t-BuOH / polyolefin(s) I advantageously ranges from 10 to 1, and preferably is 1.

[0087] Advantageously, the process according to the invention is carried out in at least one solvent allowing the solubilization of at least one polyolefin I, preferably a solvent. The solvent is advantageously chosen from chlorinated solvents such as chlorobenzene (PhCl), dichlorobenzene (PhCl2), trichlorobenzene (PhCl3) and tetrachloroethane (CH2CH2CI4).

[0088] Advantageously, the reaction allowing the introduction of the oxime groups is carried out at a temperature of up to 130°C, preferably from 100°C to 130°C, and more preferably from 110°C to 130°C.

[0089] Advantageously, the reaction allowing the introduction of the oxime groups is carried out at atmospheric pressure.

[0090] Preferably, the reaction allowing the introduction of the oxime groups is carried out away from O2, typically under an atmosphere of N2 or Ar.

[0091] Advantageously, the reaction is carried out under anhydrous conditions.

[0092] More specifically, the method according to the invention comprises the following steps:

[0093] i) having at least one polyolefin I as defined above,

[0094] ii) having at least one nitrosation agent III as defined above,

[0095] iii) adding to the at least one polyolefin I at least one nitrosating agent III, even usually at least one solvent, and possibly t-BuOH,

[0096] iv) optionally heating the reaction mixture to a temperature of up to 130°C,

[0097] v) irradiating the reaction mixture at a wavelength as defined previously, in order to obtain a polyolefin functionalized with oxime groups II.

[0098] The contents used and the nature of each of the reagents are as detailed above.

[0099] The process according to the invention may further comprise a step vi), subsequent to step v), of purification of the polyolefin functionalized with oxime groups II. This purification step may for example be carried out by precipitation of the po- lyolefin functionalized with oxime groups II. Precipitation can be followed by centrifugation(s) and / or filtration(s).

[0100] According to a first embodiment, steps 2) and 3) of the method according to the invention are carried out sequentially: the polyolefin functionalized with oxime II groups obtained in step 2) is isolated (after a possible purification step) then used in step 3).

[0101] According to a second embodiment, steps 2) and 3) of the method according to the invention are carried out successively in the same reactor: the polyolefin functionalized with oxime II groups obtained in step 2) is not isolated (therefore no purification step) and is used in step 3) by adding the reagents to the reaction mixture to carry out the reaction of step 3).

[0102] Advantageously, during step 3), all the oxime groups in the polyolefin functionalized with oxime II groups present react. However, it is conceivable to react only a part of them (for example by introducing deficient reagents), or even to react a part 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.

[0103] Various reactions can be envisaged during step 3): reduction, Beckmann rearrangement, hydrolysis, addition of isocyanate or acid chloride, etc.

[0104] According to a first embodiment, step 3) comprises, or even consists of, a reaction of an acid chloride with the oxime groups of the polyolefin functionalized with oxime groups II. 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 allowing the solubilization of the polyolefin functionalized with oxime groups II, i.e. a temperature generally ranging from 20°C to 70°C, preferably from 40°C to 60°C.

[0105] According to this embodiment, this step advantageously comprises a step of bringing the polyolefin functionalized with oxime groups II into contact with an acid chloride of formula IV:

[0106] [Chem. 15] O (IV)

[0107] With R8 representing a (Cl-C6)alkyl group, a (Cl-C6)alkylene group, an aromatic group optionally substituted by one or more (Cl-C6)alkyl or (Cl-C6)perfluoroalkyl groups.

[0108] Preferably, R8 represents Ph, p-CF3-Ph, a vinyl group (CH=CH2).

[0109] Preferably, the molar ratio of polyolefin repeat units functionalized with oxime groups II / acid chloride IV ranges from 1 / 0.9 to 1 / 1.3, preferably from 1 / 1 to 1 / 1.2, and more preferably is 1 / 1.1.

[0110] Advantageously, during this reaction, the polyolefin functionalized with oxime groups II is dissolved in at least one solvent, optionally with heating to facilitate the solubilization of the polyolefin functionalized with oxime groups II. Then the acid chloride IV and the base are added.

[0111] According to a second embodiment, step 3) comprises, or even consists of, a Beckmann rearrangement reaction. The Beckmann rearrangement is known to enable an oxime group to be transformed into an amide group. This reaction thus makes it possible to obtain a polyolefin functionalized with amide groups. According to this embodiment, the amide functions are incorporated into the polymer chain, i.e. the polymer chain is interrupted by amide functions.

[0112] 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.

[0113] It is then possible to carry out a hydrolysis reaction of the amide functions. The amide functions are then transformed into carboxylic acid functions (COOH). The hydrolysis reaction of the amide functions is usually carried out in an acidic medium. This reaction thus makes it possible to obtain carboxylic acids of variable chain length.

[0114] According to a third embodiment, step 3) comprises, or even consists of, a reduction reaction of the oxime groups into hydroxylamine groups. This reaction then makes it possible to obtain a polyolefin functionalized with hydroxylamine groups.

[0115] Reducing agents and operating conditions that can be used to reduce oxime groups to hydroxylamine groups are known in the state of the art. For example, NaBH3CN may be cited.

[0116] According to a fourth embodiment, step 3) comprises, or even consists of, a reduction reaction of the oxime groups into amine groups. This reaction then makes it possible to obtain a polyolefin functionalized with amine groups.

[0117] Reducing agents and operating conditions that can be used to reduce oxime groups to amine groups are known in the state of the art. For example, LiAlH4 may be cited.

[0118] According to a fifth embodiment, step 3) comprises, or even consists of, a hydrolysis reaction, in order to convert the oxime groups to =0.

[0119] Usually, the hydrolysis reaction is carried out by adding water, optionally mixed with a water-miscible solvent such as acetone or formaldehyde or 2,2,2-trifluoroacetophenone for example, in an acidic or basic medium.

[0120] According to a sixth embodiment, step 3) comprises, or even consists of, a reaction of an isocyanate with the oxime groups of the polyolefin functionalized with oxime groups II. Preferably, this reaction is carried out by heating the reaction mixture to a temperature allowing the solubilization of the polyolefin functionalized with oxime groups II, that is to say for example ranging from 50°C to 110°C.

[0121] According to this embodiment, this step advantageously comprises a step of bringing the polyolefin functionalized with oxime groups II into contact with an isocyanate of formula V:

[0122] [Chem. 16] N=C=O (V) Rio

[0123] with R9 and RIO being the same or different and independently representing (C1-C6) alkyl, (C6-C10) aryl groups, or an isocyanate NCO group; or R9 and RIO together represent a (C5-C8) cycloalkyl group.

[0124] Preferably, the molar ratio of polyolefin functionalized with oxime groups II / isocyanate V ranges from 1 / 0.8 to 1 / 1.2, preferably from 1 / 0.9 to 1 / 1.1, and better still is 1 / 1.

[0125] These six embodiments illustrate that the method according to the invention makes it possible to easily obtain polyolefins (or molecules of smaller molecular weight) comprising a wide variety of functional groups. It is also possible to use the known reactivity of oximes to obtain other functional groups without departing from the scope of the invention. Examples

[0126] Example 1: Study of the effect of the t-BuONO and t-BuOH content on the oxime function introduction reaction on high density polyethylene (HDPE)

[0127] Five functionalization reactions with HDPE oxime groups were carried out according to the procedure described below.

[0128] [Chem. 17]

[0129] HDPE 1-1 (1 eq., marketed by Sigma Aldrich under the reference 54799, and having a melt index of 2.2 g / 10 min at 190°C and 2.16 kg) was introduced under argon into a dry Schlenk tube equipped with a magnetic stirrer. The Schlenk tube was then placed under vacuum. Three cycles of vacuuming and purging the Schlenk tube with argon were carried out in order to eliminate all traces of air. Chlorobenzene (1.9 mL / mmol of HDPE), tert-butyl nitrite III-9 and tert-butanol were added under argon. The reaction mixture was then heated at 130°C for 30 minutes in order to solubilize the HDPE. The reaction mixture was then irradiated using a Kessil type lamp (370 nm) for 22 hours. After this period, the irradiation was stopped and the reaction mixture was cooled to room temperature (20 °C).The homogeneous solution was then added into acetone with stirring to precipitate the polymer and the medium was then transferred into two Falcon tubes to recover the functionalized polymer by centrifugation (three cycles at 5000 rpm for 10 min with an Eppendorf Centrifuge 5804 centrifuge). The recovered polymer was then placed under high vacuum (< 1 mbar) overnight before being characterized.

[0130] The reaction conditions used are detailed in Table 1 below:

[0131] [Tables 1] HDPE 1-1 t-BuONO III-9 t-BuOH Polymère fonctionnalisé oxime 120 mg 4,3 mmol leq 0,25 ml 2,15 mmol 0,5 eq 2,05 mL 21,5 mmol 5 eq IM quantitatif 121 mg 4Z3 mmol leq 0,5 mL 4,3 mmol 1 eq 4,1 mL 43 mmol 10 eq 11-2 114 mg 95 % 31 mg 1,08 mmol 1 eq 1 mL 8,6 mmol 2 eq 8,2 mL 86 mmol 20 eq II-3 quantitatif 33 mg 1,08 mmol 1 eq 2,5 mL 21,5 mmol 5 eq 20,5 mL 215 mmol 50 eq 11-4 quantitatif 240 mg 8,6 mmol 0,1 mL 0,86 mmol 0,1 eq 8,2 mmol 86 mmol 10 eq II-5 231 mg 96%

[0132] The HDPEs functionalized with oxime groups 11-1 to 11-5 obtained all show the presence of ethylenic double bonds (alkenes) and the proportion of which increases with the quantity of t-BuONO involved. This is attributable to a phenomenon of desaturation of a fraction of the ethylene units. With 2 equivalents of tert-butyl nitrite, the resulting product is identical to that described during the hydrolysis reaction of the oxime functions into carbonyl functions, i.e. a hydrolysis phenomenon is deduced. With 5 equivalents of tert-butyl nitrite, the percentage of functionalization is difficult to assess by 'H NMR due to the presence of residual water. Qualitatively, we nevertheless note the appearance of multiplets between 4.0 and 5.0 ppm, a sign of the presence of double bonds probably formed by desaturation.

[0133] The HDPEs functionalized with oxime groups 11-1 to 11-5 obtained were analyzed by NMR. The 'H NMR spectrum obtained for the oxime II-5 functionalized HDPE is shown in [Fig.l] and detailed below:

[0134] 'H NMR (600 MHz, C2D2C14, 110 ° C) ô (ppm) 2.46-2.10 (m), 1.73-1.58 (m), 1.50-1.25 (m), 1.01-0.96 (m).

[0135] A 2D HMBC NMR analysis (proton-carbon correlation in 2J and 3J) of a sample of oxime functionalized HDPE 11-5 as described above confirmed the presence of oxime groups on the polymer chain. Indeed, a correlation can be observed between the carbons present in alpha and alpha' of the oxime function and the carbon of the oxime function at 162 ppm. This type of chemical shift is characteristic of a quaternary carbon carrying an oxime function. The NMR spectrum is reproduced in [Fig.2].

[0136] The percentage of incorporation of oxime functions was then determined by integration of the 'H NMR spectrum signals. The peaks between 0.8 and 2.0 ppm (corresponding to the methylene groups) were integrated into a total of 400 protons. The protons present in the alpha and alpha' positions of the incorporated oxime function appear between 2.1 and 2.5 ppm and are used to determine the molar percentage of oxime function per repeat unit. The results obtained are detailed in Table 2 below:

[0137] [Tables2] Polymer functionalized with oxime groups molar percentage of incorporation of oxime functions ni 1.4% II-2 1.6% II-3 2.0% n-4 8.4% n-5 0.9%

[0138] The oxime 11-5 functionalized HDPE was analyzed by infrared:

[0139] IR (pure, ATR, cm1): 3397, 2914, 2847, 1462, 1261, 1086, 803, 729, 718.

[0140] The obtained oxime functionalized HDPE 11-5 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 obtained using an Agilent PL-GPC120 (high temperature) with refractive index detection, using standard solutions of polystyrene in trichlorobenzene (TCB) with BHT at 140 °C, the apparatus being equipped with a Plgel guard column and two Plgel 5 pm mixed-c columns. The results obtained were compared with those obtained with HDPE used as a reagent. The results are shown in Table 3 below.

[0141] [Tables3] Mn (g / moi) Mw (g / mol) Polydispersity index (D) HDPE 20576 203160 9.874 Nitrosylated HDPE II-5 16591 102540 6.18

[0142] Example 2: Introduction of oxime groups on hydroxypoly methylene

[0143] 1-2-hydroxypolymethylene was prepared according to the protocol described in the document by Baez et al, Ind. Eng. Chem. Res., 2017, 56, 10366-10383. The 1-2-hydroxypolymethylene obtained has a number-average molecular weight Mn equal to 3428 g / mol (determined by NMR) and equal to 3255 g / mol (determined by GPC). The 1-2-hydroxypolymethylene obtained has a mass-average molecular weight Mw of 3366 g / mol (determined by GPC) and a polydispersity index of 1.03. Size exclusion chromatography or gel permeation chromatography (GPC) was performed using an Agilent PL-GPC120 (high temperature) with refractive index detection, using polystyrene standard solutions in trichlorobenzene (TCB) with BHT at 140 °C, the instrument being equipped with a Plgel guard column and two Plgel 5 pm mixed-c columns.

[0144] The 1-2 hydroxypolymethylene was then functionalized with oxime groups, according to the protocol detailed below.

[0145] [Chem. 18]

[0146] 1-2-hydroxypolymethylene (97 mg, 3.24 mmol, 1 eq.) was introduced into a dry Schlenk tube equipped with a magnetic stirrer under argon. The Schlenk tube was then placed under vacuum. Three cycles of vacuuming and argon purging of the tube Schlenk tube were performed to remove all traces of air. Chlorobenzene (8 mL), tert-butanol (3.1 mL, 32.4 mmol, 10 eq.) and tert-butyl nitrite III-9 (0.04 mL, 0.324 mmol, 0.1 eq.) were then added to the Schlenk tube and this reaction mixture was then heated at 130 °C for 30 minutes to solubilize the hydroxy-polymethylene 1-2. The reaction mixture was then irradiated using a Kessil type lamp (370 nm) for 22 hours. After this period, the irradiation was stopped and the reaction mixture was cooled to room temperature (20 °C). The homogeneous solution was then added to acetone with stirring to precipitate the polymer. The mixture was then transferred into two Falcon tubes to recover the resulting polymer by centrifugation (three cycles at 5000 rpm for 10 min with an Eppendorf Centrifuge 5804 centrifuge).The recovered polymer 11-6 obtained was placed under high vacuum (< 1 mbar) for 12 h before being characterized (m = 95 mg, 98% conversion).

[0147] The polymer functionalized with oxime groups 11-6 was analyzed by 'H NMR:

[0148] 'H NMR (600 MHz, C2D2C14, 110 °C) δ (ppm) 3.72-3.70 (m), 2.44-2.24 (m), 1.75-1.65 (m), 1.64-1.62 (m), 1.40-1.23 (m), 1.02-0.97 (m).

[0149] The obtained 'H RMH spectrum is shown in [Fig.3].

[0150] The percentage of incorporation of oxime functions was then determined by integration of the signals from the *H NMR spectrum. Considering the composition of the polymer, the peaks between 0.8 and 2.0 ppm were integrated into a total of 400 protons. The protons present in the alpha and alpha' positions of the incorporated oxime function appear between 2.1 and 2.5 ppm and are used to determine the molar percentage of oxime function per repeat unit. Thus, it was estimated that the molar percentage of incorporation of oxime functions is 1.2%.

[0151] The obtained oxime-functionalized hydroxypolymethylene 11-6 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 obtained using an Agilent PL-GPC120 (high temperature) with refractive index detection, using standard solutions of polystyrene in trichlorobenzene (TCB) with BHT at 140 °C, the apparatus being equipped with a Plgel guard column and two Plgel 5 pm mixed-c columns. The results obtained were compared to those obtained with hydroxy-polymethylene 1-2 used as a reagent. The results are shown in Table 4, and show a small change in molecular weight distribution.

[0152] [Tables4] Mn (g / ml) Mw (g / ml) Polydispersity index (D) hydroxy-polymethylene 1-2 3255 3366 1.034 hydroxy-polymethylene nitrosylated II-6 3206 3333 1.04

[0153] Example 3: Introduction of oxime groups on low density polyethylene (LLDPE)

[0154] Low density polyethylene (LLDPE) 1-3 was functionalized with oxime groups, according to the protocol detailed below.

[0155] [Chem. 19]

[0156] LLDPE 1-3 (1 eq., 120 mg, 4.3 mmol, marketed by Sigma Aldrich under the reference 428078, and having a melt index of 1.0 g / 10 min at 190 °C and 2.16 kg) was introduced under argon into a dry Schlenk tube equipped with a magnetic stirrer. The Schlenk tube was then placed under vacuum. Three cycles of vacuuming and purging the Schlenk tube with argon were carried out in order to eliminate all traces of air. Under argon, chlorobenzene (8.3 mL), tert-butanol (4.1 mL, 43 mmol, 10 eq.), and tert-butyl nitrite III-9 (0.05 mL, 0.43 mmol, 0.1 eq.) were then added. The reaction tube was then heated at 130 °C for 30 min to solubilize LLDPE 1-3. The reaction mixture was then irradiated using a Kessil-type lamp (370 nm) for 22 h. After this period, the irradiation was stopped, and the reaction mixture was cooled to room temperature (20 °C).The homogeneous solution was then added into acetone with stirring to precipitate the polymer and the medium was then transferred into two Falcon tubes to recover the functionalized polymer by centrifugation (three cycles at 5000 rpm for 10 min with an Eppendorf Centrifuge 5804 centrifuge). The collected polymer 11-7 is then placed under high vacuum (< 1 mbar) overnight before being characterized (136 mg, 113% conversion). The excess mass obtained is due to residual traces of chlorobenzene.

[0157] The polymer functionalized with oxime groups 11-7 was analyzed by *H NMR:

[0158] 'H NMR (600 MHz, C2D2C14, 110 °C) δ (ppm) 2.46-2.24 (m), 1.68-1.60 (m), 1.52-1.26 (m), 0.98-0.95 (m).

[0159] The *H RMH spectrum obtained is represented in [Fig.4].

[0160] The percentage of incorporation of oxime functions was then determined by in-

[0161]

[0162] Integration of the 'H NMR spectrum signals. Peaks between 0.8 and 2.0 ppm (corresponding to the methylene units) were integrated over a total of 400 protons. The protons present in the alpha and alpha' positions of the incorporated oxime function appear between 2.1 and 2.5 ppm and are used to determine the molar percentage of oxime function per repeating unit. Thus, the percentage of incorporation of oxime functions was estimated to be 0.35%. The obtained oxime-functionalized polymer 11-7 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 obtained using an Agilent PL-GPC120 (high temperature) with refractive index detection, using standard solutions of polystyrene in trichlorobenzene (TCB) with BHT at 140 °C, the instrument being equipped with a Plgel guard column and two Plgel 5 pm mixed-c columns. The results obtained were compared with those obtained with LLDPE used as a reagent. The results are shown in Table 5. [Tables5]

[0163]

[0164]

[0165]

[0166]

[0167] LLDPE functionalized with oxime groups 11-7 was analyzed by infrared: IR (neat, ATR, cm1): 2914, 2847, 1462, 1370, 719. Example 4: Benzoylation of 11-6 nitrosylated hydroxypolymethylene The benzoylation reaction was carried out according to the procedure described below. [Chem. 20]

[0168] 11-6-Nitrosylated hydroxy-polymethylene (21 mg, 0.4 mmol, leq) was introduced into a two-necked, round-bottom flask equipped with a magnetic stirrer and a condenser. The flask was then placed under vacuum to perform 3 vacuum / argon cycles. Under argon, chlorobenzene (2 mL) and dichloromethane (3 mL) were added. The flask was then heated to 100 °C for 30 minutes to dissolve the polymer. 4-Trifluoromethyl benzoyl chloride (0.07 mL, 0.44 mmol, 1.1 eq) and triethylamine (0.07 mL, 0.48 mmol) were then added. The reaction mixture was left stirring overnight before being cooled to room temperature (20 °C). A saturated NaHCO3 solution (5 mL) was then added. The homogeneous solution was then added to acetone with stirring to precipitate the polymer and the medium was transferred into two Falcon tubes to recover the resulting polymer by centrifugation (three cycles at 5000 rpm for 10 min with an Eppendorf Centrifuge 5804 centrifuge). The functionalized polymer VI-1 thus recovered is placed under high vacuum (< 1 mbar) overnight before being characterized (23 mg, 109% conversion). The excess mass obtained is due to residual traces of chlorobenzene.

[0169] The functionalized polymer VI-1 was analyzed by NMR. The *H and 19F NMR spectra are shown in [Fig.5] and are detailed below:

[0170] 'H NMR (600 MHz, C2D2C14, 110 ° C) ô (ppm) 8.24-8.22 (m), 7.83-7.79 (m), 4.47-4.45 (t), 2.58-2.50 (m), 1.92-1.88 (m), 1.79-1.59 (m), 1.57-1.22(m), 1.02-0.96(m).

[0171] 19F NMR (600 MHz, C2D2C14, 110°C) ô (ppm) -62. 48, -62.56 (d, 3F)

[0172] The obtained functionalized polymer VI-1 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 obtained using an Agilent PL-GPC120 (high temperature) with refractive index detection, using standard solutions of polystyrene in trichlorobenzene (TCB) with BHT at 140 °C, the apparatus being equipped with a Plgel guard column and two Plgel 5 pm mixed-c columns. The results obtained were compared with the oxime functionalized polymer 11-6 used as a reagent. The results are shown in Table 6 below.

[0173] [Tableauxô] Mn (g / mol) Mw (g / mol) Polydispersity index (D) Nitrosylated polymer II-6 3206 3333 1.04 Functionalized polymer Vï-l 3670 3806 1.037

[0174] Example 5: benzoylation of nitrosylated HDPE 11-3

[0175] The benzoylation reaction of nitrosylated HDPE 11-3 was carried out according to the procedure described below:

[0176] [Chem.21]

[0177] Nitrosylated HDPE 11-3 (28 mg, 0.49 mmol, 1 eq) was introduced into a two-necked, round-bottom flask equipped with a magnetic stirrer and a condenser. The flask was then placed under vacuum. Three vacuum / argon cycles were then performed. Under argon, chlorobenzene (5 mL) and dichloromethane (3 mL) were added. The reaction flask was then heated at 100 °C for 30 minutes to dissolve the oxime-functionalized polyolefin 11-3. 4-Trifluoromethyl benzoyl chloride (0.08 mL, 0.54 mmol, 1.1 eq) and triethylamine (0.08 mL, 0.59 mmol, 1.2 eq) were then added. The reaction was stirred overnight. The reaction mixture was then cooled to room temperature and saturated NaHCO3 solution (5 mL) was added.The homogeneous solution was then added to acetone with stirring to precipitate the polymer and the mixture was then transferred into two Falcon tubes to recover the functionalized polyolefin by centrifugation (three cycles). The VL2 product obtained is placed under high vacuum (< 1 mbar), overnight before being characterized (27 mg, 96% conversion).

[0178] The functionalized polymer VL2 was analyzed by NMR. The *H and 19F NMR spectra are shown in [Fig.6] and are detailed below:

[0179] * H NMR (600 MHz, C2D2C14, 110 ° C) ô 8.24-8.22 (m), 7.83-7.81 (m), 2.58-2.43 (m), 1.79-1.65 (m), 1.52-1.26 (m), 1.01-0.96 (m).

[0180] 19F NMR (600 MHz, C2D2C14, 110°C) ô -62. 60 (d, 3F).

[0181] Example 6: urethanization of 11-3 nitrosylated HDPE

[0182] The urethanization reaction of nitrosylated HDPE 11-3 was carried out according to the procedure described below.

[0183] [Chem.22]

[0184] 11-3-nitrosylated HDPE (20 mg, 0.35 mmol, 1 eq) was introduced into a round-bottomed two-necked flask equipped with a magnetic stirrer and a condenser. The flask was then placed under vacuum and then performed three vacuum / argon cycles. Under argon, chlorobenzene (4 mL) and dichloromethane (4 mL) were added. The reaction flask was then heated at 100 °C for 30 minutes to dissolve the polymer. Cyclohexylisocyanate IV-1 (0.05 mL, 0.35 mmol, 1 eq) was added. The reaction mixture was left stirring overnight and then cooled to room temperature (20 °C). The homogeneous solution was then added into acetone with stirring to precipitate the polymer. The medium was then transferred into two Falcon tubes to recover the functionalized polyolefin by centrifugation (three cycles at 5000 rpm for 10 min with an Eppendorf Centrifuge 5804 centrifuge).The recovered VIL1 polymer was placed under high vacuum (< 1 mbar) overnight before being characterized (25 mg, 125% conversion). The excess mass obtained is due to residual traces of chlorobenzene.

[0185] The functionalized polymer VIL1 was analyzed by NMR. The *H NMR spectrum is shown in [Fig.7] and is detailed below:

[0186] 'H NMR (600 MHz, C2D2C14, 110 °C) ô 4.03 (br), 3.61-3.55 (m), 2.03-2.00 (m), 1.82-1.77 (m), 1.71-1.68 (m), 1.50-1.21 (m), 1.01-1.96 (m).

[0187] Example 7: introduction of oxime functions on HDPE then hydrolysis

[0188] Oxime functions were introduced onto HDPE and then these were hydrolyzed in order to obtain the corresponding polyamide.

[0189] [Chem.23] 1) t-BuONO, t-BuOH, , t PhCi, 370 nm, 130 °C M a 2) CH3COCH3 VIU-1 o

[0190] HDPE 1-1 (1 eq., marketed by Sigma Aldrich under the reference 54799, and having a melt index of 2.2 g / 10 min at 190°C and 2.16 kg) was introduced under argon into a dry Schlenk tube equipped with a magnetic stirrer. The Schlenk tube was then placed under vacuum. Three cycles of vacuuming and purging the Schlenk tube with argon were carried out in order to eliminate all traces of air. Chlorobenzene (1.9 mL / mmol of HDPE), tert-butyl nitrite III-9 (x eq.) and tert-butanol (y eq.) were added under argon. The reaction mixture was then heated at 130°C for 30 minutes in order to solubilize the HDPE. The reaction mixture was then irradiated using a Kessil type lamp (370 nm) for 22 hours. After this period, the irradiation was stopped and the reaction mixture was cooled to a temperature of (50 °C). The reaction mixture was then added into acetone (20 mL) with stirring and heated at 50°C for 1 hour. The reaction mixture was then cooled to room temperature to precipitate the polymer and then the reaction mixture was transferred into two Falcon tubes to recover the functionalized polymer by centrifugation (three cycles at 5000 rpm for 10 min with an Eppendorf Centrifuge 5804 centrifuge). The recovered polyamide VIIL1 was then placed under high vacuum (< 1 mbar) overnight before being characterized.

[0191] Polyamide VIIL1 was analyzed by NMR. The 'H NMR spectrum is shown in [Fig.8] and is detailed below:

[0192] >H NMR (600 MHz, C2D2C14, 110 °C) ô 2.45-2.40 (m), 1.80-1.60 (m), 1.52-1.26 (m), 0.98-0.95 (m).

[0193] Example 8: Nitrosation reaction on a sample of an HDPE bottle after use

[0194] A sample of HDPE bottle (132 mg, 4.71 mmol) was introduced under argon into a dry Schlenk tube equipped with a magnetic stirrer. The Schlenk tube was then placed under vacuum. Three cycles of vacuuming and purging with argon of the Schlenk tube were carried out to remove all traces of air. Chlorobenzene (8.5 mL), tert-butanol (4.5 mL, 47.8 mmol) and tert-butyl nitrite (0.07 mL, 0.471 mmol) were added to the Schlenk tube under argon. The reaction mixture was then heated at 130 °C for 30 minutes to solubilize the sample. The reaction mixture was then irradiated using a Kessil type lamp (370 nm) for 22 hours. After this period, the irradiation was stopped and the reaction mixture cooled to room temperature (20 °C). The reaction mixture was then added to acetone with stirring to precipitate the polymer.The mixture was then transferred into two Falcon tubes to recover the functionalized polymer by centrifugation (three cycles at 5000 rpm for 10 min with an Eppendorf Centrifuge 5804 centrifuge). The recovered polymer was then placed under high vacuum (< 1 mbar) for 12 h before being characterized (122 mg, 92% conversion).

[0195] The material obtained was characterized by 'H NMR:

[0196] * H NMR (600 MHz, C2D2C14, 110 ° C) ô 2.51-2.37 (m), 2.28-2.04 (m), 1.80-1.60 (m), 1.50-1.25 (m), 1.02-0.95 (m).

[0197] The NMR spectrum obtained is represented in [Fig.9].

[0198] The percentage of incorporation of oxime functions was then determined by integration of the signals from the *H NMR spectrum. Considering the composition of the polymer, the peaks between 0.8 and 2.0 ppm were integrated into a total of 400 protons. The protons present in alpha and alpha' of the incorporated oxime function which appear between 2.1 and 2.5 ppm are used to determine the molar % of nitrosation per repeating unit. Thus, it was estimated that the molar percentage of incorporation of oxime functions is 0.7% and the molar ratio of oxime functions: ketone functions is 7:3.

[0199] Example 9: Nitrosation reaction on a sample of LDPE plastic bag

[0200] A sample of LDPE plastic bag (140 mg, 4.3 mmol) was introduced under argon into a dry Schlenk tube equipped with a magnetic stirrer. The Schlenk tube was then placed under vacuum. Three cycles of vacuuming and purging the Schlenk tube with argon were carried out in order to remove all traces of air. Chlorobenzene (8.3 mL), tert-butanol (4.1 mL, 43 mmol) and tert-butyl nitrite (0.05 mL, 0.43 mmol) were then added to the Schlenk tube under argon. The reaction mixture was then heated at 130 °C for 30 minutes in order to solubilize the sample. The reaction mixture was then irradiated using a Kessil type lamp (370 nm) for 22 hours. After this period, the irradiation was stopped and the reaction mixture cooled to room temperature (20 °C).The reaction mixture was then added to acetone with stirring to precipitate the polymer. The mixture was then transferred into two Falcon tubes to recover the functionalized polymer by centrifugation (three cycles at 5000 rpm for 10 min with an Eppendorf Centrifuge 5804 centrifuge). The recovered polymer was then placed under high vacuum (< 1 mbar) for 12 h before being characterized (131 mg, 94% conversion).

[0201] The obtained material was characterized by 'H NMR:

[0202] >H NMR (600 MHz, C2D2C14, 110 °C) ô (ppm) 2.58-2.49 (m), 2.45-2.42 (m), 2.28-2.09 (m), 1.83-1.59 (m), 1.49-1.29 (m), 1.00-0.96 (m). .

[0203] The obtained NMR spectrum is represented in [Fig. 10].

[0204] The percentage of incorporation of oxime functions was then determined by integration of the signals from the *H NMR spectrum. Considering the composition of the polymer, the peaks between 0.8 and 2.0 ppm were integrated into a total of 400 protons. The protons present in alpha and alpha' of the incorporated oxime function which appear between 2.1 and 2.5 ppm are used to determine the molar % of nitrosation per repeating unit. Thus, it was determined that the molar percentage of incorporation of the oxime functions is 0.65%.

Claims

Claims

1. Method for functionalizing at least one polyolefin (I), comprising the following steps: 1) providing at least one polyolefin of formula (I): (I) Ri 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 + mt 0, 2) functionalizing the at least one polyolefin (I) with oxime groups, in order to obtain at least one polyolefin functionalized with oxime groups (II), 3) reacting the oxime groups present in the at least one polyolefin functionalized with oxime groups (II).

2. Method according to claim 1, according to which step 2) comprises the reaction, under irradiation at a wavelength belonging to the range from 300 nm to 450 nm, of the at least one polyolefin of formula (I) and of at least one nitrosating agent (III).

3. A method according to claim 2, wherein the nitrosating agent (III) is of formula (III-a), (III-b) or (III-c) below: R4x. <ni-a)’ (III-b), (III-c) ' R^ ^NO r7 n0 NO avec : - R4 et R5 étant identiques ou différents et représentant indépendamment l’un de l’autre un groupe choisi parmi (Cl-C6)alkyle, N[(Cl-C6)alkyle]3, CO[(Cl-C6)alkyle], SO2Ph, CO-Ph-CF3, - ou R4 et R5 formant ensemble un groupe (C5-C10) cycloalkyle éventuellement substitué par un ou plusieurs groupes (C1-C6) alkyle linéaire ou ramifié, ou un groupe -SO2-Ph-C(CH3)2-, ou un groupe -CO-Ph-CO-, - R6 représentant un groupe phtalimide ou un groupe (Cl-C6)alkyle linéaire ou ramifié,

4. - R7 representing an aromatic or heteroaromatic group possibly perfluorinated. Method according to claim 2 or 3 wherein the at least one .NO (HI-7), S o (in-8), and NO - \ (III-9). \\o. NO

5. Method according to any one of claims 2 to 4 according to which the molar ratio of nitrosating agent(s) (III) / polyolefin repeating units (I) ranges from 0.01 to 2, preferably from 0.1 to 0.

5.

6. A method according to any one of claims 2 to 5, wherein the reaction in step 2) is carried out in the presence of t-BuOH.

7. Method according to the preceding claim, according to which the molar ratio nitrosation agent(s) (III) / t-BuOH ranges from 0.1 to 0.01, preferably is 0.

1.

8. A method according to any one of claims 2 to 7, wherein the reaction is carried out at a temperature of up to 130°C.

9. Method according to any one of the preceding claims, according to which the at least one polyolefin (I) is chosen from polyethylene and polypropylene optionally hydroxylated in the terminal position, or an ethylene-propylene copolymer optionally hydroxylated in the terminal position.

10. A method according to any preceding claim, wherein step 3) comprises reacting at least one acid chloride with the oxime groups of the oxime-functionalized polyolefin (II).

11. A method according to any one of claims 1 to 9, wherein step 3) comprises a Beckmann rearrangement.

12. Method according to the preceding claim, according to which step 3) comprises a hydrolysis reaction in an acid medium, subsequent to the re- arrangement by Beckmann.

13. A method according to any one of claims 1 to 9, wherein step 3) comprises reducing the oxime groups of the polyolefin functionalized with oxime groups (II).

14. Method according to any one of claims 1 to 9, according to which step 3) comprises a hydrolysis reaction in an acid medium.

15. A method according to any one of claims 1 to 9, wherein step 3) comprises reacting at least one isocyanate with the oxime groups of the polyolefin functionalized with oxime groups (II).

Images