Copolymers containing polydimethylsiloxane (PDMS) parts

Abstract

The present invention relates to a method for synthesising a triblock copolymer, comprising the following steps: (1) reacting (A) a polydimethylsiloxane (PDMS) comprising at least two amine end groups, either primary amine groups (-NH2) and / or secondary amine groups (-NH(alkyl)), with (B) a molar excess, relative to all the molecules of type (A), of a molecule comprising at least two isocyanate groups (-N=C=O), in order to obtain a prepolymer terminated by isocyanate groups; (2) reacting the prepolymer obtained in step (1) with a polyamide comprising an amine end group (-NH2), the number of moles of polyamide comprising an amine end group (-NH2) being at least equivalent to the number of moles of isocyanate groups (-N=C=O) in the prepolymer obtained in step (1). The present invention also relates to a triblock copolymer obtained in this way, and to the use thereof in dressings.

Description

[0001] Description Title of the invention: Copolymers containing polydimethylsiloxane (PDMS) parts Technical Field The present invention relates to novel copolymers containing polydimethylsiloxane (PDMS) parts, the use of such copolymers in adhesive products intended to be applied to the skin, wounds, appendages and / or mucous membranes, and dressings comprising an elastomeric matrix obtained from such copolymers. Prior art Silicone elastomers are used in many fields (automotive, medical devices, childcare, optical, cosmetics, etc.). In the field of adhesives, silicone elastomers are particularly interesting in a medical context, in particular in their application to the skin, wounds, appendages or mucous membranes. They are "soft" adhesives, which are not aggressive on the skin in the sense that they are well tolerated,while offering good resistance over time. They are also repositionable, atraumatic upon removal and therefore well tolerated by the skin, particularly fragile skin such as peri-wound skin. These adhesives can be applied, removed and then reapplied without leaving any residue or causing redness. Silicones can be used at the edge of dressings or in direct contact with the wound to be treated. However, the manufacturing processes for silicone elastomers are quite complex: whether they are obtained by hot or cold vulcanization, their manufacturing process must respect very precise temperature and humidity conditions. In addition, due to the nature of the components used in their composition and their production process, silicone elastomers are expensive. In the general context of adhesive copolymers containing polydimethylsiloxane (PDMS) parts,not limited to medical-type adhesive applications such as in dressings, among the prior technologies using polysiloxanes linked to other polymer segments via isocyanate or amide groups, we can cite: - applications US 2006 / 194937 and US 2006 / 036055 which describe polydimethylsiloxane (PDMS) terminated by amino (bisaminomethyl) groups, reacted with diisocyanates; - applications US 2013 / 225768 and US 2007 / 148475 which describe a technology comprising the reaction of a PDMS diamine with diethyl oxalate, the product resulting from this reaction being able to then be reacted with diamines such as ethylene diamine. - US patent 6090902 which describes poly(ethylene-butylene) with groups in the terminal position carrying an isocyanate residue, obtained with methacryloyl isocyanate, the resulting polymer then being reacted with a PDMS carrying a methacryl group,in the presence of 2-ethylhexyl acrylate; - application US 2021 / 0009880 which describes polyolefin-polydiorganosiloxane copolymers, the synthetic route used involving the preparation of polyethylene with –SiMe2H groups in the terminal position, which can react with Si-OH groups carried in the terminal position by PDMS; - application WO 2014 / 123775 which describes polysiloxane-polyamide copolymers whose bonding is carried out by polymerization of diacids and diamines (such as hexamethylenediamine (HDMA) and adipic acid for Nylon 6,6) with the incorporation at the end of the reaction of undecylenic acid (UDA),introducing a C=C double bond that can react with a –SiH group of a siloxane; - application CN109384930 which describes a polyamide block copolymer based on a linear aliphatic chain (abbreviated in English) and polysiloxane; - application KR20170032726 which describes a polyamideimide-polydimethylsiloxane-polyamideimide (PAI-PDMS-PAI) triblock copolymer:, - application KR20160146250) which describes polymers as follows: The present invention aims to develop specific copolymers whose manufacturing process is simple and inexpensive. The compatibility of the precursors is a relevant element for an efficient synthesis of the polymers. Regarding the copolymer product obtained, together with a melting temperature that allows use in practical "hot melt" conditions with an appropriate solid-liquid transition temperature, it is appropriate to have copolymers whose melting temperature is fully reversible and whose mechanical properties are stable over time, instability in these properties being generally indicative of reactions such as additional crosslinks that occur after the initial synthesis of the copolymer. The present invention relates not only to specific copolymers but also to an elastomeric matrix obtained from such copolymers.Finally, the present invention relates to a dressing comprising such an elastomeric matrix.<Exposé de l’invention> Thus, according to a first aspect, the present invention therefore relates to a method for synthesizing a triblock copolymer comprising the following steps: (1) reaction between (A) a polydimethylsiloxane (PDMS) comprising at least two amine end groups, i.e. primary amine (-NH2) and / or secondary amine (-NH(alkyl)) groups, and (B) a molar excess, relative to all the molecules of type (A), of a molecule comprising at least two isocyanate groups (-N=C=O), in order to obtain a prepolymer terminated by isocyanate groups; (2) reaction between the prepolymer obtained in step (1) and a polyamide comprising an amine end group (-NH2), the number of moles of polyamide comprising an amine end group (-NH2) being at least equivalent to the number of moles of isocyanate groups (-N=C=O) in the prepolymer obtained in step (1).According to a particular characteristic of the invention, step (2) is carried out at a minimum temperature Tf of at least 100°C, preferably at least 130°C. Preferably, when carrying out step (2) of the method according to the invention, the quantity by mass of the prepolymer obtained in step (1) is greater than the quantity by mass of the polyamide comprising an amine terminal group. More preferably, the mass ratio between the prepolymer (comprising a PDMS core and terminated by isocyanate groups) and the polyamide provided in step (2) is at least 2 and at most 50, more preferably at least 5 and at most 40, and even more preferably at least 10 and at most 30. Thus, according to a very preferred embodiment, the quantity by mass of the polyamide comprising an amine terminal group (-NH2) is approximately one twentieth of the mass of PDMS. uréeobtained as a prepolymer. According to a particular characteristic of the invention, in the process for synthesizing a triblock copolymer: - in step (1), a reaction is carried out, preferably at a temperature of at least 25°C and at most 50°C, between at least one polydimethylsiloxane of formula (A) [Chem. 1] (A) and at least one diisocyanate of formula (B): [Chem. 2] (B) with a molar ratio (B) / (A) > 1, to obtain a prepolymer terminated by isocyanate groups of formula (C): [Chem. 3] in which - x represents an integer greater than or equal to 10; - n represents an integer greater than or equal to 1; - R1 represents saturated, linear or branched hydrocarbon groups, and R2 represents a hydrogen atom or saturated, linear or branched hydrocarbon groups; and - L1 represents a saturated, linear or branched, cyclic or acyclic hydrocarbon group, or an unsaturated, linear or branched hydrocarbon group, comprising at least one double bond and / or at least one aromatic ring; and in step (2), a reaction is carried out between the prepolymer (C) obtained in step (1) and a semi-crystalline polyamide with a melting temperature T f and comprising an amine terminal group (-NH2), of formula (D): [Chem. 4] (D) with a molar ratio (D) / (C) of more than 0 and less than 4, preferably (D) / (C) being approximately or equal to 2, at a reaction temperature T > Tf, to obtain the triblock copolymer of formula (E): [Chem. 5] in which - y and z each represent numbers greater than 0 and up to 100; - T f represents a temperature greater than or equal to 100°C. Preferably in carrying out a synthesis method according to the invention, a polydimethylsiloxane (PDMS) used in step (1) comprises at least two primary amine end groups (-NH2), and preferably comprises end groups –(CH2)3NH2and / or –(CH2)—(CH)CH3-(CH2)NH2, and / or R1 may be chosen from the following groups, the symbol * indicating a branch point: (R1-1) [Chem. 6] (R1-2) [Chem. 7] Preferably in carrying out a synthesis process according to the invention, the polydimethylsiloxane (PDMS) used in step (1) comprises at least two secondary amine end groups, preferably –NH(ethyl) or –NH(methyl) groups and / or R2 may be chosen from the following groups, the symbol * indicating a branch point: (R2-1 [Chem. 8]) (R2-2) [Chem. 9] (R2-3) [Chem. 10] Preferably in carrying out a synthesis process according to the invention, the polydimethylsiloxane (PDMS) used comprises at least two amine end groups, has a number-average molecular weight (Mn) of at least 500 g.mol -1 and at most 150,000 g.mol -1 , preferably at least 800 g.mol -1 and at most 50000 g.mol -1, and / or the number of units x is at least 10 and at most 900. More preferably, the number-average molecular mass (Mn) of the finished PDMS –NH2 used as starting material will be greater than 2000 g.mol -1 , preferably greater than 4000 g.mol -1 . Preferably in carrying out a synthesis process according to the invention, the molecule comprising at least two isocyanate groups (-N=C=O) is chosen from alkyl diisocyanates, aromatic diisocyanates or alicyclic diisocyanates. Preferably in carrying out a synthesis process according to the invention, L1 is a hydrocarbon structure such that at least 4 and at most 12 carbon atoms separate the two branching points by the shortest route, and preferably L1 is chosen from the following groups, the symbol * indicating a carbon atom forming part of the structure L1 and also being a branching point: Preferably in the execution of a synthesis method according to the invention, the molecule comprising at least two isocyanate groups (-N=C=O) is an alkyl diisocyanate whose isocyanate groups are in the terminal position, and preferably hexamethylene diisocyanate. Preferably in the execution of a synthesis method according to the invention, in step (1), the quantity used of the molecule comprising at least two isocyanate groups (-N=C=O) corresponds to a value (n+1) in number of moles, n being the number of moles of polydimethylsiloxane (PDMS) comprising at least two amine terminal groups (-NH2). Preferably in the execution of a synthesis method according to the invention, the polyamide comprising an amine terminal group (-NH2) used in step (2) has a number-average molecular weight (Mn) of less than 4000 g.mol -1 , more preferably less than 3000 g.mol -1, and even more preferably at least 500 g.mol -1 and at most 2500 g.mol -1. Preferably in the execution of a synthesis process according to the invention, the polyamide comprising an amine terminal group (-NH2) used in step (2) is chosen from: a copolymer polyamide containing units of 6 and 11 carbon atoms, preferably a copolymer between 6-aminohexanoic acid and 11-aminoundecanoic acid and / or between caprolactam and 11-aminoundecanoic acid. As indicated above, preferably, the mass ratio between the prepolymer (comprising a PDMS core and terminated by isocyanate groups) and the polyamide provided in step (2) comprising an amine terminal group (-NH2), is at least 2 and at most 50, more preferably at least 5 and at most 40, and even more preferably at least 10 and at most 30. According to a second aspect, the present invention relates to a triblock copolymer obtained according to the process of the invention.A copolymer according to the present invention may also be a triblock copolymer having the following structure: [Chem. 16]. in which: - each group (LDI 1 -LDI 2 ) corresponds to an alkyl, aromatic or alicyclic group, and preferably is a hydrocarbon structure such that at least 4 and at most 12 carbon atoms separate the two branch points by the shortest route, and preferably chosen from groups (L1-1) to (L1-5); - each group R 1 corresponds to H, Me or Et; - polydimethylsiloxane (PDMS) is connected to –NR groups 1 - by reaction of a –(CH2)3NH2 and / or –(CH2)—(CH)CH3-(CH2)NH2 terminal bond of a starting PDMS; - PA denotes a polyamide. Preferably, the mass ratio between the central part of the molecule indicated in the formula [Chem. 16], comprising a PDMS core and terminated by isocyanate groups, ending with and including the – LDI groups 1-NH-CO-, and the polyamide end parts PA-NH-, is at least 2 and at most 50, more preferably at least 5 and at most 40, and even more preferably at least 10 and at most 30. According to a third aspect, the present invention relates to the use of a triblock copolymer according to the present invention in adhesive products intended to be applied to the skin, wounds, appendages and / or mucous membranes. According to a third aspect, the present invention relates to a dressing comprising an elastomeric matrix obtained from the triblock copolymer according to the present invention. Preferably, in a dressing according to the present invention, the elastomeric matrix has through holes.In preferred dressings according to the present invention, the elastomeric matrix further contains one or more active ingredients for treating a wound, the active ingredients being selected from the group consisting of: antibacterials, antiseptics, painkillers, anti-inflammatories, healing-promoting active ingredients, and anesthetics. In preferred dressings according to the present invention, the elastomeric matrix obtained from the triblock copolymer is present in the form of an adhesive border allowing the dressing to be fixed to the skin surrounding a wound to be treated. In preferred dressings according to the present invention, the elastomeric matrix obtained from the triblock copolymer is present in the form of a film having a thickness of at least 20 µm and at most 50 µm.<Brève description des dessins> [Fig. 1] Figure 1 represents a schematic of SC-b-PDMS triblock synthesis. urée-b-SC according to the present invention. [Fig. 2] Figure 2 represents the structure (A) and DSC analysis (B) of the polyamide used. [Fig. 3] Figure 3 represents the structures and DSC analyses of the polyethylenes used: PE NH2 (A), PE NH-hexyle (B) and PE I (C). [Fig. 4] Figure 4 represents thermograms of urea prepolymers: cooling (A) and heating (B) cycles. [Fig. 5] Figure 5 represents a study of the rheological properties of urea prepolymer 1 as a function of temperature. [Fig. 6] Figure 6 represents the rheological properties of urea prepolymers during a heating cycle. [Fig. 7] Figure 7 represents the thermograms of PE NH2 , urea prepolymer and PE-b-PDMS triblock system urée -b-PE: cooling (A) and heating (B) cycles. [Fig. 8] Figure 8 represents the rheological properties of the PE-b-PDMS system urée-b-PE before (A) and after addition of PE (B) during a heating cycle. [Fig. 9] Figure 9 represents the thermograms of the PA NH2 , urea prepolymer and PA-b-PDMS triblock system urée -b-PA: cooling (A) and heating (B) cycles. [Fig. 10] Figure 10 represents the rheological properties of the PA-b-PDMS system urée -b-PA before (A) and after addition of PA (B) during a heating cycle. [Fig. 11] Figure 11 represents a reaction scheme of the polyaddition of PDMS end NH2 on HDI. [Fig. 12] Figure 12 represents a reaction scheme of the polyaddition of PA6-11 on the PDMS prepolymer urée . [Fig. 13] Figure 13 represents a DSC thermogram of the PDMS prepolymer urée [Fig. 14] Figure 14 represents a DSC thermogram of the PA-b-PDMS triblock urée -b-PA. [Fig. 15] Figure 15 represents the G' and G'' modules of PA-b-PDMS urée-b-PA as a function of temperature during a heating cycle. [Fig. 16] Figure 16 represents the stress versus elongation curve of the PA-b-PDMS system urée -b-PA. [Fig. 17] Figure 17 represents a reaction scheme of the two-step synthesis of PA-b-PDMS urée éth .-b-PA. [Fig. 18] Figure 18 shows a DSC thermogram of a PA-b-PDMS triblock urée éth .-b-PA. [Fig. 19] Figure 19 represents the rheological properties of the PA-b-PDMS system urée éth .-b-PA during the second heating cycle. [Fig. 20] Figure 20 represents a reaction scheme of the two-step synthesis of PA-b-PDMS urée / urée éth.-b-PA. [Fig. 21] Figure 21 represents the storage moduli of urea / ethyl urea prepolymers as a function of the urea fraction at room temperature. [Fig. 22] Figure 22 represents the evolution of G' as a function of the urea fraction at 25 °C (A); sol / liq transition temperature as a function of the urea fraction (B). [Fig. 23] Figure 23 represents a stress curve as a function of strain (A), maximum elongation (B) and elastic moduli as a function of the % of urea group (C) of PA-b-PDMS systems urée / urée éth .-b-PA. [Fig. 24] Figure 24 represents the evolution of the elastic modulus, G', and the viscous modulus G'', as a function of temperature in the case of the PA-b-PDMS triblock urée -b-PA. [Fig. 25] Figure 25 represents the evolution of the elastic modulus, G', and the viscous modulus G'', as a function of temperature in the case of the PA-b- PDMS triblock uréthane-b-PA.<Description des modes de réalisation> The triblock copolymers according to the present invention comprise a polydimethylsiloxane (PDMS), linked by isocyanate-derived regions to a polyamide. In the context of the present invention, for the preparation of such copolymers, the compatibility of the PDMS and polyamide precursors is a relevant element for an efficient synthesis of the polymers. The polyamide part can strongly influence the final mechanical properties of the material (high elastic modulus, very low deformation under stress).Along with the issue of final mechanical properties, it is noted that a goal is also to prepare copolymers containing a polysiloxane block (such as PDMS) and semi-crystalline blocks, so that the semi-crystalline nodules are physical crosslinking nodes, which can be reversibly formed and destroyed by applying suitable temperature ramps, thus allowing reversible transition from an "elastic solid" state to a "viscous liquid" state. Preferably, the semi-crystalline blocks will have a melting temperature that is within the target temperature range of at least 100 °C and at most 140 °C.In this context, it has been observed by the inventors that some products obtained from PDMS precursors having hydroxyl groups along the chain and terminal epoxide groups, transformed into a copolymer by reaction with a secondary diamine such as NN-dimethyl-1,6-hexanediamine, are not satisfactory in an industrial context because the liquid-solid transition of the materials is not reversible. It seems that a parasitic reaction leads to the chemical (i.e. irreversible) crosslinking of the materials. Thus, after a storage period of a few weeks, the materials can no longer be melted in the form of a viscous liquid. They can no longer be easily solubilized in a solvent either.The inventors postulate that the pendant hydroxyl groups are involved in a parasitic reaction leading to the crosslinking of the PDMS phase, in particular with residual epoxy groups, or with the terminal ester functions of the polyamide (PA). According to the present invention, a PDMS terminated by amine functions is first reacted with a diisocyanate spacer, a preferred example of diisocyanate being hexamethylene diisocyanate. The ratio between reactants is chosen so that the PDMS prepolymers. urée are terminated by isocyanate functions. The second synthesis step then consists of adding the monofunctional semi-crystalline polymer, terminated by an NH2 function, which will be able to react with the terminal isocyanate functions of PDMS prepolymers, to lead to the formation of SC-b-PDMS triblock copolymers urée-b-SC, where SC = semi-crystalline. The approach is described in Figure 1. It is considered that the potential advantages of this approach are multiple: 1. Urea functional groups are known to develop strong hydrogen bonds (N–H⋯O). Their presence along the PDMS chain should allow the development of intra-chain physical interactions within the PDMS phase, which in turn should make it more cohesive. This should improve the mechanical properties of the material, in particular its strain rates at break. 2. Urea functional groups are polar and should therefore allow good reactive compatibilization between PDMS prepolymers urée and polyamide, PA. In a particularly preferred embodiment of the present invention, the polyamide (PA) part used in the preparation of the copolymer of the invention is a PA copolymer 6 / 11containing mixed 6-carbon and 11-carbon units. A polymer of this type is commercially available, supplied by ARKEMA under the trade name APOLYA, with proportions of PA6 and PA 11 of about 0.3 and 0.7 respectively (by mass) with a molar mass M n = 2500 g.mol -1 , terminated at one end by a primary amine function and at the other by a methyl ester function (see Figure 2, part A). According to one aspect, the present invention relates to a triblock copolymer having the following structure: (PA)-(NH-CO-NH)-(LDI1)-[(PDMS urea) n (PDMS alkyl urea) m ]-(LDI1)-(NH-CO- NH)-(PA) in which: PA represents a polyamide block; NH-CO-NH represents a urea bond; LDI1 represents a linker group which can be derived from a diisocyanate chain portion; the -[(PDMS urea) n (PDMS alkyl urea) m]- represents an entity comprising n PDMS groups integrated into the copolymer by urea groups and m PDMS groups integrated into the copolymer by urea alkyl groups, n and m being integers and the PDMS urea and PDMS urea alkyl groups being present in separate blocks or mixing in the chain constituting the part -[(PDMS urea) n (PDMS alkyl urea) m]- ; the elements (PDMS urea) having repeating units represented by the formula -[(LDI2)-(NH-CO-NH)-(LSX1)-(PDMS)-(LSX1)-(NH-CO-NH)-(LDI2)]- in which: LDI2 represents a linker derivable from a diisocyanate chain portion; NH-CO-NH represents a urea bond; LSX1 represents a linker between the urea group and the silicon atom at the end of the poly(dimethyl)siloxane (PDMS) chain; the elements [(PDMS urea alkyl) having repeating units represented by the formula -[(LDI2)-(NH-CO-NR)-(LSX2)-(PDMS)-(LSX2)-(NH-CO-NR)-(LDI2)]- in which: LDI2 represents a linker derivable from a diisocyanate chain portion; NH-CO-NR represents an alkyl urea bond, R being an alkyl group of at least 2 carbon atoms, preferably ethyl; LSX2 represents a linker between the urea group and the silicon atom at the end of the poly(dimethyl)siloxane (PDMS) chain.According to the aspect of the invention cited above, preferably the combined linker elements LDI1-LDI2, LSX1 and LSX2 each correspond to an alkyl, aromatic or alicyclic group, and preferably to a hydrocarbon structure such that at least 4 and at most 12 carbon atoms separate the two branching points by the shortest route, and preferably the linkers LDI1-LDI2, LSX1 and LSX2 correspond to a group L1 chosen from the following groups, the symbol * indicating a carbon atom forming part of the structure L1 and also a branching point:. (L1-4) [Chem. 20] (L1-5) [Chem. 21] According to this aspect, the polydimethylsiloxane(s) (PDMS) present, at one or more units in the overall structure of the copolymer, have for each PDMS unit (used during the synthesis) a number-average molecular mass (Mn) of at least 500 g.mol -1 and at most 150,000 g.mol -1 , preferably at least 800 g.mol -1and at most 50000 g.mol -1, and / or the number of units x is at least 10 and at most 900.<Matrice élastomérique> According to one aspect, the present invention relates to an elastomeric matrix obtained from the triblock copolymers according to the invention as described above. In particular, the elastomeric matrix can be obtained by hot physical transformation according to methods well known to those skilled in the art. The elastomeric matrices thus obtained can be used in various devices, such as, for example, dressings. In order to produce dressings, the matrix according to the invention will preferably be formed as a thin layer. According to a preferred embodiment of the invention, the matrix has through holes. The through holes can be made by perforation or by punching the matrix previously formed as a thin layer. Alternatively,the matrices in accordance with the invention can be manufactured by hot casting a polymer composition as described above onto a plate engraved with the chosen pattern to form through holes, followed by a cooling step and finally a demolding step. The production of adhesive dressings generally meets complex specifications in order to reconcile contradictory characteristics. The main criteria to be verified for such a dressing are essentially to have good breathability while avoiding the risk of leaks, and to be impermeable to liquids and bacteria while being breathable (i.e. permeable to water vapor). Preferably, the dressing will maintain its cohesion when removed once loaded with exudates, and will preferably be easy to manufacture. The dressing must also be easy to apply and remain in place for as long as possible without damaging the peri-wound skin. Preferably,it will not impair wound healing when removed. The dressing must finally fit the patient's morphology. The elastomeric matrix is ​​preferably thin, so as to better fit the shape of the body and follow movements without risking detachment. The adhesive support is advantageously conformable. Generally speaking, the elastomeric matrices in accordance with the invention have a thickness of between 15 µm and 2 mm. The elastomeric matrix will preferably be impermeable to external fluids and pathogenic microorganisms while ensuring permeability to water vapor,so as to prevent both contact of the wound with external liquids and bacteria and maceration of the wound. The elastomeric matrix is ​​preferably adhesive so as to keep the dressing in place. The matrix may contain active ingredients that have a beneficial role in wound treatment. Among the substances that may be used in the context of the present invention as active ingredients, we may, by way of examples, cite: - antibacterials such as, for example, silver derivatives such as silver salts or other metals (for example, silver sulfate, chloride or nitrate and silver sulfadiazine), silver complexes or other metals (for example, silver zeolites such as alphasan, or ceramics), metrodinazole, neomycin, Polymyxin B, penicillins (Amoxycillin), clavulanic acid, tetracyclines, Minocycline, chlortetracycline, aminoglycosides, Amikacin,Gentamicin or probiotics; - antiseptics such as chlorhexidine, triclosan, biguanide, hexamidine, thymol, Lugol, Povidone iodine, Benzalkonium and Benzethonium Chloride; - painkillers such as Paracetamol, Codeine, Dextropropoxyphene, Tramadol, Morphine and its derivatives, Corticosteroids and derivatives; - anti-inflammatory drugs such as glucocorticoids, non-steroidal anti-inflammatory drugs, aspirin, ibuprofen, ketoprofen, flurbiprofen, diclofenac, aceclofenac, ketorolac, meloxicam, piroxicam, tenoxicam, naproxen, indomethacin, naproxcinod, nimesulide, celecoxib, etoricoxib, parecoxib, rofecoxib, valdecoxib, phenylbutazone, niflumic acid, mefenamic acid; - active ingredients promoting healing such as retinol, vitamin A, vitamin E, N-acetyl-hydroxyproline, centella asiatica extracts, papain, thyme essential oils,of niaouli, rosemary and sage, hyaluronic acid, polysulfated oligosaccharides and their salts (in particular synthetic sulfated oligosaccharides having 1 to 4 sugar units such as the potassium salt of octasulfated sucrose or the silver salt of octasulfated sucrose), sucralfate, Allantoin, urea, metformin, enzymes (for example proteolytics such as streptokinase, triestin or collagenase), peptides or protease inhibitors; - anesthetics such as benzocaine, lidocaine, dibucaine, pramoxine hydrochloride, bupivacaine, mepivacaine, prilocaine, or etidocaine. In the context of the present invention, it is possible to envisage matrices which are easy to handle, repositionable, allow painless removal when applied to the skin, mucous membranes or appendages, and have satisfactory durability over time. <pansements>The present invention also relates to a dressing comprising the elastomeric matrix obtained from triblock copolymers according to the invention. According to a preferred embodiment of the invention, the present application aims to cover an absorbent dressing comprising an elastomeric matrix in the form of an adhesive border which can take the form of a "sidewalk", and allowing the dressing to be fixed to the skin surrounding the wound. These dressings, in particular when used for the treatment of particularly painful chronic wounds, are advantageously conformable and thin in order to limit the tensions that the dressing can generate on the surface of the skin. According to a preferred embodiment of the invention, the adhesive absorbent dressing comprises the assembly of an absorbent layer and the elastomeric matrix forming the sidewalk of the absorbent dressing, which is respectful of the fragile and sensitive peri-wound skin.According to a preferred embodiment of the invention, the present application aims to cover an absorbent dressing comprising an absorbent layer coated with an elastomeric matrix in the form of a perforated coating. The through holes allow the passage of exudates towards the absorbent layer. The elastomeric matrix is ​​present over the entire surface of the dressing in contact with the skin. Advantageously, this type of dressing does not adhere to wet wounds but adheres to the peri-wound skin, thus allowing removal without trauma or pain. Among the known dressings of this type, the products marketed by the company Mölnlycke under the brand Mepilex®, can be cited.According to a preferred embodiment of the invention, the present application aims to cover a self-supporting interface dressing comprising an elastomeric matrix in the form of a thin layer having through holes to allow exudates to pass through. The thickness of such a dressing is preferably between 0.4 and 2 mm. In order to protect the matrix from the external environment, the interface dressing may be covered, preferably on each of its faces, by a temporary protective film which will be removed before use by the user. Among the known dressings of this type, the products marketed by URGO Laboratories under the brand UrgoTul® may be cited. According to a preferred embodiment of the invention, the present invention aims to cover a dressing composed of an elastomeric matrix in the form of a thin transparent adhesive film. The thickness of such a dressing is preferably between 20 and 50 µm.The transparency allows visual control of the area to be treated. These films are semi-permeable, they are permeable to gas exchange, and are impermeable to liquids and bacteria. They provide mechanical protection against friction, friction and shearing. Among the known dressings of this type, the products marketed by the company Smith & Nephew under the brand Opsite®, or by the company 3M under the brand Tegaderm® or by Laboratoires URGO under the brand Optiskin®, can be cited. According to a preferred embodiment of the invention, the present invention aims to cover a dressing composed of an elastomeric matrix in the form of a flexible gel plate having through holes. These dressings, in particular when used in the treatment of hypertrophic or keloid scars, are advantageously self-adhesive and conformable in order to adapt to each scar.Among the known dressings of this type, the products marketed by the company Smith & Nephew under the brand Cica-care®, can be cited. By dressing, is meant in the present invention any medical device of the dressing type comprising at least one elastomeric matrix. In particular, the invention applies to dressings used for the treatment of wounds, the treatment of scars and cosmetic patches. <exemples><Réactifs>All raw materials used are commercially available. The characteristics of all products are listed in Table 1 below.<a) Polymères semi-cristallins> Two semi-crystalline polymers were used, a polyamide and a polyethylene. These polymers differ in many aspects. For example, polyethylene has an inert structure while polyamide has many amide functions on its chain. Being semi-crystalline and each having melting temperatures between 100 and 130°C, they are potentially promising candidates for the preparation of thermoplastic elastomers. Regarding the question of possible incompatibility between the polymer components, polyethylene does not show strong incompatibility with PDMS, polyethylene having a lower solubility parameter than polyamide with a δ value PE = 16 MPa 1 / 2 . <polyamide>PA copolymer 6 / 11 is supplied by ARKEMA under the trade name APOLYA. The proportions of PA6 and PA 11 were determined by NMR analysis 1 H and are respectively 21% by weight and 79% by weight. This low molar mass copolymer (M n = 2500 g.mol -1 ) is terminated at one end by a primary amine function and at the other by a methyl ester function (Figure 2, part A). It has melting temperatures, T f ~130°C, and crystallization, T f ~105°C, which were measured by DSC (Figure 2, part B).<Polyéthylène> Polyethylene is obtained from Activation. More precisely, it consists of three types of low molar mass monofunctional polyethylenes that differ in their terminal functions. The first is an iodized terminated polyethylene (PE I ) of molar mass defined by SEC (M w = 1039 g.mol -1 ). This polyethylene is the precursor for obtaining the other two primary amine terminated polyethylenes (PE NH2 ) and secondary amine (PE NH-hexyle ) of molar masses, defined from the PE substrate I , respectively 929 and 1013 g.mol - 1 In DSC, these polyethylenes exhibit bimodal melting peaks as shown in Figure 3. For low molar masses, the presence of bimodal peaks appears to be linked to two crystal sizes due to a fraction of non-functional polyethylene (C. Soulié-Ziakovic, Macromolecules, 2015, 48, pp. 3257-3268).<b) PDMS> The PDMS used were supplied by Gelest, Genesee Polymers and ABCR. The exact molar masses were systematically calculated from the NMR data. 1 H using trichlorobenzene as an internal standard. These products were used without further treatment.<PDMS amines primaires pendantes> These PDMS will be noted PDMS graft NH2 . Their chemical formula is shown below. A polymer with a molar mass of M n ~50000 g.mol -1 with 6-7% aminopropylmethylsiloxane unit (trade name AMS-163 at Gelest) was used. [Chem. 22] <PDMS terminé amines primaires> These PDMS will be noted PDMS end NH2 . Their chemical formula (PDMS terminated at each end by an aminopropyl group) is shown below. A polymer with a molar mass of M n ~5000 g.mol -1 was used (trade name DMS-A21 at Gelest and AB109371 at ABCR). [Chem. 23] <PDMS terminé amines secondaires> These PDMS will be noted PDMS end NH . Their chemical formula (PDMS terminated at each end by an N-ethylaminoisobutyl group) is shown below. A polymer with a molar mass of M n ~2500 g.mol -1 at 3500 g.mol -1 was used (trade name DMS-A214 at Gelest). [Chem. 24] <Techniques d’analyse et caractérisation><a) Résonance magnétique nucléaire (RMN)>Due to varying solubilization conditions, NMR analysis parameters are separated according to the products concerned. • PDMS blocks: NMR 1 H on Bruker Avance 400 spectrometer in deuterated chloroform at 25°C. • Products containing polyamide: NMR 1 H on Bruker Avance 400 spectrometer in a mixture of deuterated chloroform and anhydrous trifluoroacetic acid at 25°C (6:1). • Products containing polyethylene: NMR 1 H on Bruker Ascend 400 Prodigy spectrometer in deuterated chloroform at 70°C. The spectra are processed and analyzed on the Topspin software provided by Bruker.<b) Calorimétrie différentielle à balayage (DSC)> Thermograms of the samples are obtained using the DSC Q100 device marketed by TA ® instruments, equipped with a liquid nitrogen refrigeration system. Samples with masses between 5 and 10 mg are introduced into sealed aluminum capsules and then analyzed using the following procedure: - Equilibrium at -150 °C - 1 ère heats up to 150°C with a ramp of 10°C / min - Isotherm 1 min at 150°C - Temperature drop to -150°C at 10°C / min - Isotherm 1 min at -150°C - 2 ème heats up to 200 °C with a ramp of 10 °C / min The glass transition, crystallization and melting temperatures are determined after erasing the thermal history of the materials during the 1 ère heated.<c) Rhéologie> Rheological measurements were performed on the Anton Paar MCR rheometer. Measurements were made with a 8 mm diameter plane-plane geometry for solid or particularly viscous samples. For the least viscous samples, a 25 mm diameter cone-plane geometry was preferred. Two types of measurements were performed: - A frequency sweep: measurement of the elastic modulus (G') and the loss modulus (G'') as a function of the shear rate at a constant angular frequency at 25°C - A temperature sweep: measurement of G' and G'' as a function of temperature (ramp of 3.6 °C / min) at a constant shear rate and an angular frequency of 10 rad / s. During these measurements, the sample was placed on the low geometry at 150 °C. The first analysis is performed during cooling from 150 to 25 °C. The second analysis corresponds to heating the sample from 25 to 150°C.<d) Test de traction>Tensile tests were performed on an MTS QTest 25 at room temperature. Measurements were made on dogbone-shaped specimens approximately 40 mm long, 4 mm wide, and 1 mm thick. Deformations were applied at a rate of 5 mm / min.<e) Diffraction et diffusion des rayons X (DRX)> The DRX material analyses were carried out in a partner laboratory, the CRPP, on a Xeuss 2.0 device marketed by Xenocs. This device delivers a beam with an energy of 8 keV. The data are collected on a DECTRIS PILATUS-300k detector placed at different distances from the sample, thus giving access to the angle range 0.03° to 50° (0.025 nm. -1 at 34.5 nm -1 ). Table 1 below summarizes the commercially available semi-crystalline polymers and PDMS polymers experimentally explored by the present inventors in the preparation of polymers according to the present invention and comparative polymers. [Table 1] Molar Masses Name Names Names i- s Commercial -1 nation aux (g.mol ) (Supplier) (Supplier data) Polyamide 6-11 PA 6-11 APOLYA (Arkema) 2500 Mono-terminated polyethylene iodine PE I PE-I (Activation) 1039 Mono-terminated amine polyethylene PE NH2 PE-NH2 (Activation) 929 N-hexyl mono-terminated polyethylene PE NH-hexyle PE-NH-hexyl (Activation) 1013 PDMS end DMS-E12 epoxy 1000 (Gelest) 1000-1400 Polydimethylsiloxane terminated DMS-E21 epoxypropoxypropyl PDMS end (Gelest) é poxy 5000 GP504 4500-5500 (Genesee Polymers) Mono-terminated polydimethylsiloxane PDMS end MCR-E11 epoxypropoxypropylemono epoxy (Gelest) 5000 Copolymer (6-7% aminopropylmethylsiloxane)- PDMS graft AMS-163 5 00 ethylsiloxane (Geles 00 sun NH2 t) DMS-A21 Polydimethylsiloxane terminated PDMS end (Gelest) aminopropyl NH2 AB109371 5000 (Gelest) N-ethylaminoisobutyl terminated polydimethylsiloxane PDMS end NH DMS-A214 (Gelest) 2500-3000 Table 1 presents a summary of the data concerning the commercial products used<Réacteurs> The various reactions were carried out in glass reactors consisting of a glass tube or flask and a glass or Teflon mechanical stirrer under nitrogen flow. A Radleys 6 Plus carousel was also used to run up to 6 reactions in parallel. <Chimie isocyanate-amine><Systèmes triblocs SC-b-PDMS urée -b-SC> The synthesis of these triblock copolymers is carried out in two stages (Figure 1): 1. Synthesis of the prepolymer: reaction between the PDMS end NH2 and hexamethylene diisocyanate with excess diisocyanate to obtain isocyanate-terminated prepolymers. 2. Addition of the primary amine-terminated semi-crystalline polymer. <i) Prépolymère PDMS urée > The primary objective in the synthesis of this type of prepolymer was to observe the reactivity between the isocyanate and the primary amine located at the end of a PDMS chain. Several materials with a molecular weight gradient were prepared to observe the influence of chain length on thermal and rheological properties.<Synthèse> To do this, three materials were synthesized to obtain amine-terminated prepolymers. These materials differ in the ratio r = [isocyanate] / [NH2], so the quantities of material introduced are listed in Table 2 below. For these syntheses, a PDMS end NH2 supplied by ABCR (AB109371) and having a molar mass of 5800 g.mol -1 was used. The reactions were carried out in the carousel at room temperature with mechanical stirring. [Table 2] M cn Conversion NH d 2 Sample mab H DI g mPDMSend NH2g r Theoretical DPn - % (NMR) kg.mol1 1 0.066 2.42 0.95 39 120 90 2 0.048 1.83 0.90 19 60 86 3 0.050 2.05 0.85 12.3 40 83 Table 2 presents data relating to the synthesis of PDMS prepolymers urée terminated primary amines [Math. 1] As soon as the two precursors are brought into contact by mechanical stirring, a significant increase in viscosity can be observed. Thus, due to an almost instantaneous reaction, kinetic monitoring could not be carried out. The products obtained are transparent elastic solids that can be shaped. NMR analysis 1 H allowed the measurement of the conversion rate of the amine functions. According to the results obtained by analyzing the evolution of the intensity of the peak corresponding to the alpha protons of the NH2 group, we can conclude that there is a complete reaction between the isocyanates and the primary amines (Conversion NH2 ~ 100 xr). The remaining amines in the systems correspond to the chain ends of the synthesized prepolymers. As expected, the reactive compatibility between the two precursors allows a total conversion with reaction conditions of time and temperature perfectly compatible with a reactive extrusion process. Therefore, it is possible to imagine the synthesis of urea prepolymers with primary amine or isocyanate terminations and presenting various concentrations in urea function using PDMS end NH2 various molar masses. Attempts to synthesize urea prepolymers were carried out with a PDMS precursor end NH2 of lower molecular mass (AB109370 with Mn = 3200 g.mol -1 ). This change in precursor leads to an increase in the concentration of functional groups. The high reactivity then leads to the production of solid materials in a liquid PDMS phase.<Caractérisation> <dsc>The thermal phase transitions of the materials presented in Table 2 were analyzed by DSC. These materials were obtained from the same precursors introduced in varying proportions in order to obtain three distinct molar masses. The thermal cycles are described in the experimental part. Figure 4, part B, represents the 2 nd heating cycles of the three samples. In all cases, we observe a first inflection point, around -120 °C, characteristic of the glass transition of PDMS (T g PDMS). Only sample 3 shows an exothermic peak and an endothermic peak, between -80 and -40 °C, corresponding to the crystallization and melting of the PDMS. While the prepolymers obtained by the epoxy-amine route did not show any other thermal transition than that mentioned above, DSC analyses of the urea prepolymers systematically show an endothermic peak around 20 °C. This peak can then be attributed to a melting in a phase constituted by the stacking of the urea groups. The inflection points relating to the T g as well as the crystallization of the urea phase are observable during cooling (Figure 4, part A). The values ​​of T g (PDMS), T f (urea) and ∆H f (urea) are reported in Table 3 for all samples. For clarity, the fusion enthalpies of the urea groups have been reduced to one mole of urea and expressed in kJ.mol -1 . [Table 3] T g T f ΔH f ΔH f r = [isocyanate] / PDMS Sample Urea Urea Urea [amine] °C °C Jg-1 kJ.mol-1 1 0.95 -123.55 20.15 0.85 5.36 2 0.90 -123.29 19.64 0.82 5.44 3 0.85 -123.64 19.25 0.76 5.35 PDMS end NH2 / -123.36 / / / Table 3 presents characteristics of the thermal phase transitions of urea prepolymers and PDMS precursor end NH2 measured by DSC The glass transition temperatures of PDMS obtained are identical and have a value of -123.5 °C for all the synthesized prepolymers. This value is equal to that of the PDMS precursor end NH2 . Thus, the introduction of urea groups by reaction of HDI isocyanate on PDMS end NH2 does not influence the glass transition temperature of the PDMS phase. Similarly, the T g of PDMS is not impacted by the chain length of "decorated" PDMS with identical values ​​for the three synthesized materials. Finally, the enthalpies of fusion, ∆H f , urea phases were measured. Samples 1 (r = 0.95), 2 (r = 0.90) and 3 (r = 0.85) have melting temperatures of 20.15; 19.64 and 19.25 °C respectively. A slight decrease in T f is observed with decreasing concentration in urea function. Consistently, the fusion enthalpy values ​​decrease from 0.85 to 0.76 Jg -1 between samples 1 and 3. Once reduced to enthalpy values ​​in kJ.mol -1 , all samples have identical values ​​of 5.4 kJ.mol -1 .<Propriétés rhéologiques> Preliminarily, the linearity domain of urea prepolymers was measured by performing a shear rate scan at constant temperature and angular frequency. Thus, all the mechanical properties presented here were obtained in plane-plane mode (8 mm diameter geometry) with a shear rate, γ = 5% and an angular frequency, ω = 10 rad.s -1 . G' and G'' were analyzed during a cooling cycle from 150 to 25 °C and heating from 25 to 150 °C (1.3 °C / min). Figure 5 represents the storage (G') and loss (G'') moduli of sample 1. The sample was placed on the geometry at 150 °C, at this temperature the material is a viscous liquid. The mechanical properties are first measured during cooling, we can then observe a transition from a liquid state (G' < G'') to a solid state (G' > G'') at a temperature of 69 °C (G' = G''). During heating, this transition temperature is measured at 89 °C. This hysteresis between the heating cycle and the cooling cycle is consistent with the difference between the crystallization temperature and the melting temperature of the urea domains measured by DSC.A slight increase in the G' modulus is observed around 80 °C, this may reflect an incomplete conversion during the reaction or a shift of the sample in the geometry. The drastic drop in G' modulus observed during heating to a temperature of around 110 °C cannot be fully explained. It only reflects a significant drop in viscosity in this temperature range. At these modulus values, of the order of Pa, the analysis comes up against the limits of the apparatus. This phenomenon is also present during cooling with a drastic increase in G' at around 80 °C. At 25 °C, sample 1 behaves like an elastic solid with modulus values ​​G' = 230 kPa and G'' = 62 kPa. These values ​​are relatively low and are consistent with the macroscopic appearance ("soft" materials). The comparison of the mechanical properties of the three urea prepolymers of varying molar mass is presented in Figure 6.Only the heating cycles are shown. The hysteresis phenomenon described for sample 1, between heating and cooling, was observed for all the materials studied. The three synthesized urea prepolymers exhibit similar behavior: "soft" elastic solid at room temperature and viscous liquid at a temperature above the transition temperature (T. sol / liq ). However, these phase change temperatures are a function of chain length. Sample 1 (M n théorique = 120 kg.mol -1 ) shows a transition at 89 °C, sample 2 at 56 °C (M n théorique = 60 kg.mol -1 ) and sample 3 at 47°C (M n théorique = 40 kg.mol -1 ). Similarly, the values ​​of G' and G'' vary depending on the molar mass. All the data obtained are summarized in Table 4. [Table 4] T sol / liq T sol / liq G' G'' M n théorique Sample cooling heating T = 35 °CT = 35 °C kg.mol-1 °C °C kPa kPa 1 120 69 89 160 38 2 60 42 56 69 35 3 40 37 47 21 13 Table 4 presents a summary of the rheological properties of urea prepolymers The increase in the molar mass of the synthesized urea prepolymers, from 40 to 120 kg.mol -1 , has two effects on the rheological properties. The first is an increase in the storage (21 to 160 kPa at 35 °C) and loss (13 to 38 kPa at 35 °C) moduli. The second is an increase in the solid / liquid transition temperature (47 to 89 °C during heating). The increase in chain length results in an increase in entanglement and in the concentration of urea groups as seen in thermal analysis (DSC). Thus, the length of the prepolymer can strongly influence intra- and inter-chain interactions and therefore the mechanical properties. <conclusion>These first attempts at synthesizing urea prepolymers are of great interest due to their synthesis conditions (short time and room temperature) and their mechanical strength. The materials obtained are flexible and reprocessable. However, the sol / liq transition temperatures are relatively close to room temperature. Thus, the addition of a crystalline polymer to these urea "decorated" PDMS systems appears to be an appropriate solution for obtaining thermally stable, reprocessable flexible materials. <ii) Triblocs PE-b-PDMS urée -b-PE (PE Comparative Examples)> The realization of PE-b-PDMS triblock systems urée -b-PE (PE = polyethylene) is made possible by the presence of functional groups at each end of the PDMS prepolymer urée .<Synthèse> In order to facilitate comparison between PE-b-PDMS systems urée -b-PE and PA-b-PDMS urée -b-PA, the prepolymer used is identical and has the characteristics listed in Table 5 below. The molar mass of PDMS end NH2 used is 5827 g.mol -1 . [Table 5] Urea prepolymer (PDMS urée ) Isocyanate Termination r = [amine] / [isocyanate] 0.95 M [kg. -1 n théorique mol ] 120 Table 5 shows characteristics of the PDMS prepolymer urée used for the synthesis of SC-b-PDMS triblocks urée -b-SC The addition of a semi-crystalline polymer to the prepolymer is described in 2 ème step of the synthesis scheme of Figure 1. The prepolymer being terminated at each end by an isocyanate function, it can therefore react directly with a polyethylene mono-functionalized by a primary amine. The quantity of polyethylene to be reacted with the prepolymer is calculated by considering a conversion of 100% of the primary amines during the synthesis of the isocyanate-terminated prepolymer. The polyethylene is then added in a ratio [1:1] with the isocyanate functions present at each end of the PDMS prepolymer urée according to the following equation (1): [Math. 2] Experimentally, the prepolymer is preheated in a flask to 150 °C to be in a molten state. Polyethylene, which has a melting temperature of approximately 100 °C, is then added to the reaction medium. The quantities of material introduced for the synthesis of the PE-b-PDMS system urée -b-PE are presented in Table 6: [Table 6] PDMS urée PE NH2 Sample mass M n théorique mass M n % by weight g kg.mol-1 g PE-b-PDMS urée -b-PE 2.288 120 0.032 929 1.4 Table 6 presents experimental data of the synthesis of the PE-b-PDMS system urée -b-PE As with the synthesis of the urea prepolymer, the kinetics of this reaction could not be studied. Thus, the reaction time was determined from visual observations. First, the polyethylene melts into the PDMS phase. A two-phase system is then initially observed with a transparent low-viscosity phase on the edges of the flask (PDMS urée ) and a more viscous and opaque phase around the mechanical stirring blade. Within a few minutes, the system homogenizes with a single opaque and more viscous phase. The material obtained after one hour at 150 °C (overestimation of the reaction time) is a slightly translucent white "soft" elastic solid. This can be shaped and reshaped by placing it in an oven at 150 °C in a silicone mold. Confirmation of the creation of a covalent bond between the prepolymer and the polyethylene could not be carried out due to the superposition of peaks during NMR analysis. Similarly, the difference in molar masses between the prepolymer and the triblocks was not observed in size exclusion chromatography due to a small mass difference of the order of a percent.Nevertheless, visual observations during the synthesis as well as dispersion tests of non-functionalized polyethylene in the urea prepolymer seem to indicate the obtaining of the PE-b-PDMS triblock system. urée -b-PE. For this reaction, it is important to note the low mass proportion of polyethylene. With the available precursors, increasing this mass fraction can only be done by decreasing the molar mass of the prepolymer (increasing the number of chain ends for a given mass).<Caractérisation> <dsc>Phase transitions of the PE-b-PDMS system urée -b-PE were analyzed by DSC. For clarity, the obtained thermogram is compared with those of the urea prepolymer and PE NH2 in Figure 7. The values ​​of T g of PDMS can be identified during the heating cycle in Figure 7, part B. These glass transition temperatures are thus not influenced by the addition of polyethylene with values ​​of -123.4 °C for the urea prepolymer and -123.3 °C for the triblocks. On the contrary, the melting temperatures of the urea and polyethylene domains are modified. Indeed, when PE is added, T f (urea) decreases and goes from 20 to 14°C and T f (PE) increases from 97 to 114 °C. The enthalpy of fusion of polyethylene, ∆H f PE = 1.03 J / g -1 , allows access to the crystallinity rate of the polyethylene phase, χ PE = 36%. This value is much lower than that of the PE NH2 alone, which is 80%. All of these results seem to indicate the presence of a phase where urea and polyethylene groups coexist. X-ray diffraction analysis is a technique that can confirm this conclusion.<Propriétés rhéologiques> To facilitate comparison between the different systems, the conditions for measuring the G' and G'' moduli of the urea prepolymer triblock systems are identical to the conditions set for the urea prepolymers. That is, a shear rate, γ = 5% and an angular frequency, ω = 10 rad.s -1 with a cooling and heating ramp of 1.3°C.min -1 Figure 8 shows the storage (G') and loss (G'') moduli during a heating cycle of the PE-b-PDMS triblock system. urée -b-PE before (urea prepolymer) and after addition of polyethylene. With the addition of polyethylene at each end of the prepolymer, the sol / liq transition temperature increases from 53 to 58 °C. Similarly, the G' modulus increases from 73 to 90 kPa. Thus, the mechanical and thermal properties of the material are only slightly improved by the presence of the semi-crystalline polyethylene polymer. This result is explained by the low mass proportion of PE in the system (1.4%) and by the melting temperature of PE close to 100 °C. <conclusion>The synthesis of PE-b-PDMS triblocks urée -b-PE is of interest due to the problem of having synthesis conditions suitable for industrial processes. The resulting materials are flexible and reprocessable. However, the low thermal stability of the system is a barrier to its use. <iii) Triblocs PA-b-PDMS urée -b-PA> The polyamide 6 / 11 used here has a molar mass of 2500 g.mol -1 whereas polyethylene has a molar mass of less than 1000 g.mol -1 . Thus, for the use of the same prepolymer, the mass fraction of semi-crystalline polymer is multiplied by approximately 2.5 in the case of the polyamide supplied by Arkema. In addition, the melting temperature of this polyamide is much higher than that of polyethylene with a T f = 130 °C.<Synthèse> For the synthesis of the PA-b-PDMS triblock system urée -b-PA, the urea prepolymer used is identical to that used during the synthesis of PE-b-PDMS urée -b-PE. Its characteristics are listed in Table 7. The addition of polyamide to PDMS urée is carried out in the same way as for polyethylene and corresponds to the second step shown in Figure 1. The prepolymer is heated to 150 °C with mechanical stirring, the polyamide is then added through the neck of the flask and the reaction is continued until a homogeneous mass is obtained. The material obtained is an opaque elastic solid with a non-adherent surface; it can be shaped into a bar or film in an oven at 150 °C. As a reminder, the quantity of polyamide to be reacted with the prepolymer is calculated by considering a 100% conversion of the primary amines during the synthesis of the isocyanate-terminated prepolymer. The quantities of material used in this synthesis are given in Table 7. The mass proportion of semi-crystalline polymer is here 4.1%. [Table 7] PDMS urée PA NH2 Sample mass M n théorique mass M n % by weight g kg.mol-1 g PA-b-PDMS urée -b-PA 2.312 120 0.098 2500 4.1 Table 7 presents experimental data of the synthesis of the PA-b-PDMS system urée -b-PA As previously for systems containing urea groups, the reaction kinetics could not be studied due to the superposition of the urea and isocyanate peaks with those of the polyamide in NMR analysis. The reaction was monitored using visual observation such as the transition from a two-phase system with a dense and opaque phase around the stirring blade and a transparent phase to a homogeneous system. The creation of a covalent bond between the prepolymer and the polyamide could be observed during a DOSY experiment. This experiment showed a difference in diffusion index between the prepolymer and the PA-b-PDMS triblocks urée -b-PA.<Caractérisation> <dsc>Phase transitions of the PA-b-PDMS system urée -b-PA were analyzed by DSC. For clarity, the obtained thermogram is compared with those of the urea prepolymer and PA 6-11 in Figure 9. As shown by the thermograms in Figure 9, part B, obtained during the second heating cycle, the glass transition temperature is unchanged upon addition of the polyamide, with values ​​of -123.4 °C for the prepolymer and -123.9 °C for the PA-b-PDMS triblocks urée -b-PA. Unlike the prepolymer and the system containing polyethylene, the system with polyamide no longer shows an endothermic peak around 15-20 °C (urea domains). This can be explained by a greater interaction between the amide groups of the polyamide and the ureas contained in the PDMS chain. Finally, thermal analysis by DSC allows observing the presence of an endothermic peak corresponding to the melting of the crystalline phase of the polyamide. This temperature is 130 °C for the polyamide alone and 131 °C for the triblock system. The enthalpy of fusion of the polyamide, ∆H f PA = 1.23 J / g -1 , allows access to the crystallinity rate of the polyethylene phase, χ PA = 10.5%. This value is lower than that of the PA NH2 alone, which is 19%. Again, these results seem to indicate the presence of a phase where the urea and polyamide groups coexist.<Propriétés rhéologiques> The storage (G') and loss (G'') moduli of the PA-b-PDMS system urée -b-PA, over a temperature range from 25 to 150 °C, are presented in Figure 10, part B and compared to those of the urea prepolymer (Figure 10, part A). The rheological analysis firstly allows the observation of a significant increase in the sol / liq transition temperature between the prepolymer and the triblock system with respective values ​​of 53 and 82 °C. The G' modulus also increases significantly with the addition of polyamide, going from 70 kPa for the urea prepolymer to a value of 330 kPa. This increase was expected with the addition of a higher mass proportion than with the addition of polyethylene (4.1% and 1.4%). These semi-crystalline polymers creating "hard" nodules within the final material naturally increase the elastic moduli. Finally, the PA-b-PDMS triblock material urée -b-PA exhibits good thermal resistance with a slight decrease in mechanical properties up to a temperature close to 80°C. <conclusion>Compared to the use of polyethylene in relation to the prepolymer, the impact of polyamide is very promising. Indeed, its use combined with a PDMS "decorated" with urea functions allows the production of reprocessable elastic solid materials with properties better corresponding to those sought in the context of the present invention. Indeed, these materials are both flexible, elastic and meltable at a relatively high temperature. <iv) Montée en échelle du système Triblocs PA-b-PDMS urée -b-PA> Until now, the synthesis of materials has been carried out from a quantity of precursors of the order of 2 to 5 grams. The aim here is to verify the potential for scaling up the synthesis of the PA-b-PDMS system urée -b-PA. To do this, the synthesis was carried out from 50 g of PDMS end NH2 .<Synthèse> As seen previously, the synthesis of this type of triblock is carried out in two stages. First, a prepolymer containing urea groups is synthesized. This is terminated at each end by an isocyanate function so that in the second stage it can react with the mono-functionalized polyamide with a primary amine. <1 ère step: synthesis of the PDMS prepolymer urée > The prepolymer is synthesized from hexamethylene diisocyanate (HDI) and a PDMS terminated at each end by a primary amine function. This PDMS end NH2 is not identical to that used in the synthesis of the systems presented in sub-parts i, ii and iii. This is a new batch ordered from ABCR (AB109371) which has a molar mass of 47200 g.mol -1 (analyzed by NMR). The difference in molar mass with the previous batch leads to a change in the concentration of urea group, here, it is an increase with the decrease in molar mass (5800 to 4700 g.mol -1 ). This difference explains the gap between the properties of the PA-b-PDMS system urée -b-PA presented in subsection iii and those presented below. For the synthesis of PDMS prepolymer urée (Figure 11), the ratio [NH2] / [NCO] is 0.95. Thus, the theoretical molar mass of the prepolymer is 93000 g.mol -1 . Experimentally, 50 g of PDMS end NH2 were placed in a 100 mL three-necked flask under nitrogen flow at room temperature. The diisocyanate is added directly into the PDMS using a syringe under vigorous mechanical stirring. During some scale-up tests, non-homogeneous products with viscosity gradients were observed. Considering that this is likely due to the significant reactivity between primary amines and isocyanates, a small volume of THF was added to the diisocyanate, in order to reduce this reactivity, this volume not representing more than 5% by mass of precursors. Thus, a gradual addition of the THF / HDI solution (~50 / 50 by volume) allows a "controlled" reaction. The solidification is of the order of a minute and mechanical stirring is then no longer efficient. The medium is then placed at a temperature of 150 °C to melt, lower the viscosity of the product and ensure maximum conversion.The conversion of primary amines to urea is finally monitored by NMR. 1 H. This analysis allows us to observe the elimination of THF introduced earlier. <2 ème step: Addition of the polyamide> The reaction mixture being already placed at a temperature above T f of the polyamide used (T f = 130 °C), the addition of PA can be done directly while stirring. The medium becomes opaque and whitens in a few minutes. The product could then be shaped to obtain films of approximately 0.5 and 1 mm thickness. This shaping was carried out in a silicone mold by allowing the product to flow at a temperature of 150 °C. <conclusion>When switching from 2 to 50 g synthesis of PA-b-PDMS copolymer urée -b-PA, the high reactivity of the system causes a sudden solidification which was controlled with the use of a small amount of solvent (less than 5% by weight). However, this solvent disappears very quickly (confirmation by NMR). The reaction times, of the order of one minute to ten minutes, are short. A protocol for monitoring the 2 ème This reaction step will need to be developed to obtain a more precise reaction time. This experiment confirms that scaling up is easy and could be considered in particular in reactive extrusion.<Caractérisation> The mechanical properties of the material were studied by rheology and tensile testing, the thermal properties by DSC. <dsc>The measurements presented were carried out between -75 and 150°C. The thermograms presented correspond to the second heating of the material. The DSC analysis of the isocyanate-terminated PDMS prepolymer is presented in Figure 13. The characteristic melting temperature of the urea groups of the prepolymer, around 25°C, can be observed. After the 2 ème synthesis step, the addition of polyamide, the melting temperature of PA can be observed at 130 °C (Figure 14).<Propriétés rhéologiques> For rheology analyses, the material is placed at room temperature and directly melted at 150 °C to adapt to the 8 mm plane-plane geometry. After analysis of the moduli during cooling, the storage and loss moduli are measured during heating from 25 to 150 °C with a ramp of 1.3 °C.min -1 (γ = 5% and ω = 10 rad.s -1 ) and presented in Figure 15. The sol / liq phase transition temperature is measured at approximately 116 °C. At 25 °C, the storage modulus has a value of 412 kPa. These two results are, as expected, higher than those obtained during syntheses with a PDMS precursor end NH2 of higher molar mass. Indeed, the increase in the concentration of urea group leads to an increase in inter- and intramolecular hydrogen interactions and therefore an increase in moduli and thermal stability. The absence of an increase in modulus at high temperature suggests a complete reaction during the balloon synthesis. This result is also in agreement with the macroscopic appearance of the material, which does not have a "sticky" appearance.<Test de traction> The measurements of the modulus of elasticity (E') and the elongation at break were carried out by tensile testing. To do this, a constant speed deformation was applied to 6 samples cut with a die in the shape of a "dogbone". The results obtained are reproducible and only the measurement with the highest elongation at break is shown in Figure 16. Tensile analysis of the PA-b-PDMS system urée -b-PA shows typical behavior of an elastic solid at low deformation. It is therefore possible to determine a value of modulus of elasticity, E' = 108 kPa, from the linear domain. The material has an elongation at break of 44%. <v) Systèmes triblocs PA-b-PDMS urée éth. -b-PA> PA-b-PDMS systems urée -b-PA show strong potential, but nevertheless it is still possible to try to improve the mechanical properties of the designed systems by playing on the nature of the bonds created between the PDMS and the spacer. The replacement of PDMS end NH2 by a PDMS end NH thus makes it possible to obtain ethylated urea groups and to reduce inter and intramolecular interactions by crowding the group.<Synthèse> In the following, polyamide 6-11 is used as a semi-crystalline polymer. The reaction scheme of the two-step synthesis of PA-b-PDMS urée éth. -b-PA is shown in Figure 17. The PDMS end NH used here is supplied by Gelest (DMS-A214) and has a molar mass of 1900 g.mol -1 The experimental conditions for the synthesis of this type of triblocks are identical to those presented during the synthesis of PA-b-PDMS systems. urée -b-PA. The total quantities of material used are listed in Table 8. [Table 8] r = m HDI m ntillon PD m PA6-11 % by weight Echa MSend NH (n NH / n NCO ) ggg PA 6-11 PA-b-PDMS urée éth. -b-PA 0.95 0.3371 3.5924 0.5737 12.7 Table 8 presents experimental data of the synthesis of the PA-b-PDMS system urée éth. -b-PA The 1 ère synthesis step consists of synthesizing an ethylated urea prepolymer terminated at each end by an isocyanate function. NMR analysis 1 H allows to observe the total conversion of primary amines and to control the presence of isocyanates at the end of chains. When the product obtained has solidified and is homogeneous, the reaction is considered complete and the product is then heated to 150 °C to be able to introduce the polyamide. The polyamide is added directly into the reaction medium under stirring. The medium quickly becomes opaque and whitens. The white material obtained exhibits mechanical behavior at the boundary between liquid and solid and particularly strong adhesion to glass or metal. It is worth noting the high mass fraction of polyamide of 12.7% by weight. This difference is linked to the low molar mass of the PDMS precursor. end NH .<Caractérisation> <dsc>DSC thermal analysis of PA-b-PDMS material urée éth. -b-PA is shown in Figure 18. This figure shows the cooling cycle followed by the second heating cycle. In this thermogram, the glass transition temperature of PDMS can be observed at -120 °C. This temperature is close to the reference value of the PDMS used in this study (-123.5 °C). An analysis of the PDMS precursor end NH will allow us to conclude on the difference in values ​​of T g The endothermic melting peak and the exothermic crystallization peak of polyamide are present at temperatures of 129 (T f PA ) and 108°C (T c PA ). These values ​​are consistent with the expected and already observed values. From the fusion enthalpy value, ∆H f PA = 3.71 Jg -1 , it is possible to access the crystallinity rate of the polyamide phase, χ PA = 12.2%. This rate is higher than that obtained on PA-b-PDMS systems urée -b-PA (χ PA = 10.5%) and therefore closer to the crystallinity of PA alone (χ PA = 19.0%). This result indicates a more pronounced phase separation with the use of ethyl urea groups. Unlike systems containing urea groups, no melting peak is observed around 15-20 °C. However, the presence of a low inflection point between 0 and 50 °C may provide information on a state transition of the ethyl urea phase.<Propriétés rhéologiques> The storage (G') and loss (G'') moduli, during the second heating cycle, of the PA-b-PDMS system urée éth. -b-PA, over a temperature range from 25 to 150 °C, are shown in Figure 19. At a temperature of 25 °C, the storage and loss moduli have respective values ​​of 84 and 77 kPa. These two values ​​are particularly close and explain the behavior observed at the end of the synthesis. Although G' is greater than G'', the material does not exhibit the behavior of a classical solid. At low stress frequencies, the material appears close to a viscous liquid (partial flow in the pillbox), whereas at high stress frequencies, the material behaves like a solid. The sol / liq transition temperature is here 107 °C but does not reflect a change of state with a very small delta between G' and G' over the entire temperature range studied. <conclusion>The introduction of ethyl urea-type bonds has made it possible to obtain materials with strong adhesion properties. In addition, these bonds can reduce interactions between the “decorated” PDMS chains compared to urea bonds. <vi) Systèmes triblocs PA-b-PDMS urée / urée éth. -b-PA> Based on results obtained on PA-b-PDMS systems urée -b-PA and PA-b-PDMS urée éth. -b-PA and due to similar reaction conditions, it is quite possible to imagine synthesizing materials with intermediate properties with a mixture of urea and ethyl urea groups. In these materials, cohesion can be ensured by the urea bonds and adhesion properties by the ethyl urea bonds.<Synthèse> For this part on PA-b-PDMS triblock copolymers urée / urée éth. -b-PA, four materials were synthesized with varying urea / ethyl urea ratios. The precursors used for these syntheses are a PDMS end NH2 with a molar mass of 4728 g.mol -1 , a PDMS end NH with a molar mass of 1887 g.mol -1 and hexamethylene diisocyanate (HDI). The reaction scheme for this type of reaction allows the production of PA-b-PDMS systems urée / urée éth. -b-PA is presented in Figure 20. The experimental parameters for these syntheses are listed in Table 9. Sample 1 (100 wt% urea) corresponds to the sample presented in the scale-up part of the PA-b-PDMS system urée -b-PA. For all syntheses, the ratio r = (n amines / nisocyanates) = 0.95.

[0002] [Table 9] % in % in m HDI mmab M n thé % by weight weight orique Sample PDMSend PDMSend weight g PDMSend PDMSend -1 N H g NH2 g kg.mol PA 6-11 NH NH2 11,885 0 50,351 0 100 93 5,8 20,155 0,747 2,259 25 75 80 7,7 30,180 1,203 1,801 40 60 72 8,5 40,219 1,698 1,670 50 50 66 9,3 Table 9 presents data relating to the synthesis of PA-b-PDMS system urée / urée éth. -b-PA [Math. 3] a% by weight PDMS NH = , b % by weight PDMS NH2 = The two synthesis steps proceed in a similar way to those presented so far in the section on isocyanate-amine chemistry. Once formed into a film by flow in an oven at 150 °C, the materials show strong macroscopic differences (Figure 23). While samples 1 and 2 are white, sample 3 is slightly translucent. Sample 4 is relatively close to transparent. These observations provide information on the dimensions of the polyamide nodules within the material. The second difference concerns the adhesion properties of the materials. Adhesion is greatly increased with increasing the fraction of ethyl urea groups.<Caractérisation> <dsc>[Table 10] T g T f ΔH f M n théorique % in ^ ^^^^^^ Sample % urea PDMS PA 6-11 PA 6-11 weight kg.mol-1 PA % Jg- 6-11 °C °C 1 1100 93 -123.4 127.9 1.91 5,8 14 2 75 80 -122.98 128.9 2.01 7,7 11 3 60 72 -122.65 129.1 2.69 8,5 13 4 50 66 -122.3 127.6 3.10 9,3 14 Table 10 presents characteristics of thermal phase transitions of PA-b-PDMS systems urée / urée éth. -b-PA measured by DSC The glass transition temperatures of PDMS measured for the 4 materials are very close with values ​​ranging from -123.4 °C for the sample with 100% urea group and -122.3 °C for 50% urea. Generally, a slight increase is observed with the increase in the fraction of ethylated urea. Analysis of the PDMS precursor end NH will allow us to conclude on the difference in values ​​of T g . The melting temperatures of polyamide are very close and contained between 127.6 and 129.1 °C. These values, depending on the analysis of the thermograms, will be considered identical. Finally, the melting enthalpy values ​​of the crystalline phase of the polyamide allow the calculation of the crystallinity rate. These rates are between 11 and 14%, but it is impossible to conclude on the differences without analyzing the dimensions and phase separation using a technique such as XRD.<Propriétés rhéologiques> The storage (G') and loss (G'') moduli of the 4 materials and their 4 associated prepolymers were obtained by rheological analyses. First of all, the behavior of the prepolymers should be noted. Surprisingly, the prepolymers corresponding to materials 1 and 4 appear as solids (G' > G'') at room temperature, while prepolymers 2 and 3 are liquids (G' < G'').The G' values ​​for all prepolymers are presented in Figure 21 and summarized in Table 11. After addition of polyamide, these four elastic solid materials show a decrease in storage moduli with increasing ethylated urea fraction (Figure 22, part A). Indeed, G' goes from 410 kPa for 100% urea to a value of 74 kPa for 50% urea. This is explained by the decrease in inter- and intramolecular hydrogen interactions. For the same reason, a decrease in the sol / liq transition temperature, from 117 to 83 °C, is observed with decreasing urea fraction (Figure 22). [Table 11] PA-b-PDMS prepolymer. urée / urée -b-PA % PDMS éth. urea / urea eth. Urea sample G' 25°C G'' 25°C G' 25°C G'' 25°CT sol / liq kPa kPa kPa kPa °C 1 100 73 40 410 94 117 2 75 0.2 2 321 75 115 3 60 2 6.5 283 92 135 4 50 23 24 74 47 83 Table 11 provides a summary of the rheological properties of PDMS prepolymers urée / urée éth. and PA-b-PDMS systems urée / urée éth. -b-PA<Test de traction> The elastic modulus (E') and elongation at break measurements of the 4 materials were obtained by tensile testing. For each material, 6 dogbone-shaped specimens were analyzed. The stress-strain curves were obtained during deformation at a constant speed (5 mm / min). The results obtained are reproducible and presented in Figure 23. Tensile analysis of PA-b-PDMS systems urée / urée éth .-b-PA shows typical behavior of an elastic solid at low deformation. It is therefore possible to determine the values ​​of the modulus of elasticity from the linear domains. In Figure 23, part C, a linear relationship can be observed between the modulus of elasticity and the rate of urea groups. By going from 100% urea to 50%, the modulus E' changes from a value of 108 to 7 kPa. The introduction of 50% ethylated urea allows the modulus of elasticity to be reduced by a factor greater than 10. Similarly, Figure 23, part B, shows the relationship between λ max and the urea content. Thus, the maximum elongation at break increases from 44 to 95% between 100 and 50% urea (factor 2). These two results are consistent with the modification of hydrogen interactions induced by the presence of hindered urea groups. The summary of the results is given in Table 12. [Table 12] E' λ max Sample % urea kPa % 1 100 108 44 2 75 80 53 3 60 30 62 4 50 7 95 Table 12 provides a summary of the mechanical properties of PA-b-PDMS systems urée / urée éth. -b-PA <conclusion>Synthesis of PA-b-PDMS systems urée / urée éth .-b-PA did not show any difference with the synthesis of PA-b-PDMS systems urée -b-PA. Reaction times remain in the order of one to ten minutes at temperature and pressure conditions compatible with industrial processes. Partial replacement of the PDMS precursor end NH2 by a PDMS precursor end NH allows the production of flexible and reprocessable materials with a wide range of properties. Indeed, the introduction of this new precursor leads to the creation of hindered urea groups within the final material. Thus, the reduction of intra and intermolecular interactions allows a reduction of the storage moduli E' and G' in parallel with an increase in elongation at break. Finally, these materials have interesting adhesion properties, the presence of ethylated urea group leading to an increase in these properties.<Comparaison avec copolymère tribloc obtenu à partir d’un PDMS-OH> In this study, a PA-b-PDMS type triblock copolymer urée -b-PA, obtained from a commercial NH2-terminated PDMS, is compared with a triblock copolymer of the PA-b-PDMS type uréthane -b-PA, obtained from a commercial OH-terminated PDMS. Both copolymers are synthesized using the protocol described above in this application. Comparison of these two copolymers allows observing the properties of a commercial OH-terminated PDMS. The diagram above shows the synthesis of a copolymer according to the invention obtained by an NH2 terminated PDMS, and the diagram below shows the synthesis of a comparative copolymer obtained by an OH terminated PDMS. Finished PDMS material OH, PDMS OH (M n = 5860 g.mol -1 measured by NMR 1 H) and PDMS terminated NH2, PDMS NH2 (M n = 5210 g.mol -1 measured by NMR 1 H) supplied by GELEST. The two PDMS only differ in the nature of their chain end (OH vs NH2). Hexamethylene Diisocyanate supplied by Sigma-Aldrich. Polyamide 6-11 supplied by Arkema (APOLYA, M n = 2500 g.mol -1 , 18 wt% PA6- 82 wt% PA 11 , T f = 130°C). Synthesis ^ Synthesis of PA-b-PDMS urée -b-PA Urea prepolymer, PDMS urée , was made by reaction between 10 g of PDMS precursor NH2 and 358 mg of hexamethylene diisocyanate (r = [amine] / [isocyanate] = 0.90). PDMS urée obtained is then heated to 150°C with mechanical stirring and 945 mg of polyamide is added to give the triblock copolymer PA-b-PDMS urée -b-PA desired. At 150 °C, it appears as an opaque white solution. After cooling, the sample forms a soft viscoelastic solid. ^ Synthesis of PA-b-PDMS uréthane -b-PA Urethane prepolymer, PDMS uréthane , was made by reaction between 10 g of PDMS precursor OH molar mass and 319 mg of hexamethylene diisocyanate (r = [amine] / [isocyanate] = 0.90). PDMS uréthane obtained is then heated to 150°C with mechanical stirring and 973 mg of polyamide is added to give the triblock copolymer PA-b-PDMS uréthane -b-PA desired. At 150 °C, it appears as an opaque, slightly orange solution. After cooling, the sample remains in liquid form. Study of rheological properties In order to confirm the visual observations, the two copolymers were studied in rheology. They were subjected to a temperature ramp (3.6 °C.min- 1 ) between 20 °C and 100 °C with a shear rate γ = 5% and an angular frequency ω = 10 rad.s -1 Figure 24 represents the evolution of the elastic modulus, G', and the viscous modulus G'', as a function of temperature in the case of the PA- triblock b -PDMS urée-b - PA. Clearly, for temperatures between 20 °C and 60 °C, the elastic modulus is higher than the viscous modulus (G' > G''), which means that the material behaves like an elastic solid. We also observe that G' ~ 100 kPa, a low value which is characteristic of the mechanical behavior of a "soft" material. Above 60 °C, G' < G'', the material becomes liquid. Figure 25 represents the evolution of G' and G'' as a function of temperature in the case of the PA-b-PDMS triblock uréthane -b-PA. This time G' < G'' over the entire temperature range, which confirms that the material still has a liquid behavior, including at room temperature. Conclusions To conclude, these two experiments demonstrate that the simple modification of the terminal functions of the NH2-terminated PDMS precursors by OH functions drastically changes the final mechanical behavior of the PA-b-PDMS-b-PA triblocks.< / conclusion> < / dsc> < / conclusion> < / dsc> < / dsc> < / conclusion> < / conclusion> < / dsc> < / conclusion> < / dsc> < / conclusion> < / dsc> < / polyamide> < / exemples> < / pansements>

Claims

Claims

1. A method for synthesizing a triblock copolymer comprising the following steps: (1) reaction between (A) a polydimethylsiloxane (PDMS) comprising at least two amine end groups, either primary amine (-NH2) and / or secondary amine (-NH(alkyl)) groups, and (B) a molar excess, relative to all the molecules of type (A), of a molecule comprising at least two isocyanate groups (-N=C=O), in order to obtain a prepolymer terminated by isocyanate groups; (2) reaction between the prepolymer obtained in step (1) and a polyamide comprising an amine end group (-NH2), the number of moles of polyamide comprising an amine end group (-NH2) being at least equivalent to the number of moles of isocyanate groups (-N=C=O) in the prepolymer obtained in step (1).

2. A process for synthesizing a triblock copolymer according to claim 1, step (2) being carried out at a minimum temperature Tf of at least 100°C, preferably at least 130°C.

3. A process for synthesizing a triblock copolymer according to claim 1 or 2, wherein the mass ratio of the prepolymer terminated by isocyanate groups obtained in step (1), relative to the polyamide provided in step (2), is at least 2 and at most 50, more preferably at least 5 and at most 40, and even more preferably at least 10 and at most 30.

4. A process for synthesizing a triblock copolymer according to any one of claims 1 to 3, wherein: - in step (1), a reaction is carried out, preferably at a temperature of at least 25°C and at most 50°C, between at least one polydimethylsiloxane of formula (A). [Chem. 1] (A) and at least one diisocyanate of formula (B): [Chem. 2] (B) with a molar ratio (B) / (A) > 1, to obtain a prepolymer terminated by isocyanate groups of formula (C): [Chem. 3] in which - x represents an integer greater than or equal to 10; - n represents an integer greater than or equal to 1; - R1 represents saturated, linear or branched hydrocarbon groups, and R2 represents a hydrogen atom or saturated, linear or branched hydrocarbon groups; and - L1 represents a saturated, linear or branched, cyclic or acyclic hydrocarbon group, or an unsaturated, linear or branched hydrocarbon group, comprising at least one double bond and / or at least one cycle aromatic; and in step (2), a reaction is carried out between the prepolymer (C) obtained in step (1) and a semi-crystalline polyamide with a melting temperature T f and comprising an amine terminal group (-NH2), of formula (D): [Chem. 4] (D) with a molar ratio (D) / (C) of more than 0 and less than 4, preferably (D) / (C) being approximately or equal to 2, at a reaction temperature T > Tf, to obtain the triblock copolymer of formula (E): [Chem. 5] in which - y and z each represent numbers greater than 0 and up to 100; - T f represents a temperature greater than or equal to 100°C.

5. A synthesis method according to any one of claims 1 to 4 wherein a polydimethylsiloxane (PDMS) used in step (1) comprises at least two primary amine end groups (-NH2), and preferably comprises –(CH2)3NH2and / or –(CH2)—(CH)CH3-(CH2)NH2 end groups, and / or R1 may be selected from the following groups, the symbol * indicating a branch point: (R1-1) [Chem. (R1-2) [Chem. 7]

6. A synthesis process according to any one of claims 1 to 5 wherein a polydimethylsiloxane (PDMS) used in step (1) comprises at least two secondary amine end groups, preferably –NH(ethyl) or –NH(methyl) groups and / or R2 may be selected from the following groups, the symbol * indicating a branch point: (R2-1 [Chem. 8]) (R2-2) [Chem. 9] (R2-3) [Chem. 10]

7. A synthesis process according to any one of claims 1 to 6, wherein the polydimethylsiloxane (PDMS) used, comprising at least two amine end groups, has a number-average molecular weight (Mn) of at least 500 g.mol -1 and at most 150,000 g.mol -1 , preferably at least 800 g.mol -1 and at most 50000 g.mol -1, and / or the number of units x is at least 10 and at most 900.

8. A synthesis process according to any one of claims 1 to 7, wherein the molecule comprising at least two isocyanate groups (-N=C=O) is chosen from alkyl diisocyanates, aromatic diisocyanates or alicyclic diisocyanates.

9. A preparation process according to any one of claims 4 to 8, wherein L1 is a hydrocarbon structure such that at least 4 and at most 12 carbon atoms separate the two branching points by the shortest route, and preferably L1 is chosen among the following groups, the symbol * indicating a carbon atom forming part of the L1 structure and also being a branch point: (L1-1) [Chem. 11] (L1-2) [Chem. 12] (L1-3) [Chem. 13] (L1-4) [Chem. 14] (L1-5) [Chem. 15]

10. A synthesis process according to claim 8, wherein the molecule comprising at least two isocyanate groups (-N=C=O) is an alkyl diisocyanate whose isocyanate groups are in the terminal position, and preferably hexamethylene diisocyanate.

11. A synthesis process according to any one of claims 1 to 10, wherein, in step (1), the amount used of the molecule comprising at least two isocyanate groups (-N=C=O) corresponds to a value (n+1) in number of moles, n being the number of moles of polydimethylsiloxane (PDMS) comprising at least two amine end groups (-NH2).

12. A synthesis process according to any one of claims 1 to 3, wherein the polyamide comprising an amine end group (-NH2) used in step (2) is selected from: a copolymer polyamide containing units of 6 and 11 carbon atoms, preferably a copolymer between 6-aminohexanoic acid and 11-aminoundecanoic acid and / or between caprolactam and 11-aminoundecanoic acid.

13. A triblock copolymer obtained according to the process of any one of claims 1 to 12.

14. A triblock copolymer having the following structure: [Chem. 16] in which: - each group (LDI 1 -LDI 2 ) corresponds to an alkyl, aromatic or alicyclic group, and preferably to a group as defined in claim 8; - each group R 1corresponds to H, Me or Et; - polydimethylsiloxane (PDMS) is connected to –NR groups 1 - by reaction of a –(CH2)3NH2 and / or –(CH2)—(CH)CH3-(CH2)NH2 terminal bond of a starting PDMS; - PA denotes a polyamide.

15. Use of a triblock copolymer according to one of claims 13 or 14 in adhesive products intended to be applied to the skin, wounds, appendages and / or mucous membranes.

16. Dressing comprising an elastomeric matrix obtained from the triblock copolymer according to one of claims 13 or 14.

17. Dressing according to claim 16, in which the elastomeric matrix has through holes.

18. Dressing according to claim 16 or 17, in which the elastomeric matrix further contains one or more active ingredients for the treatment of a wound, the active ingredients being chosen from the group consisting of: antibacterials, antiseptics, painkillers, anti-inflammatories, active ingredients promoting healing, and anesthetics.

19. A dressing according to any one of claims 16 to 18, wherein the elastomeric matrix obtained from the triblock copolymer is present in the form of an adhesive border allowing the dressing to be fixed to the skin surrounding a wound to be treated.

20. A dressing according to any one of claims 16 to 19, wherein the elastomeric matrix obtained from the triblock copolymer is present in the form of a film having a thickness of at least 20 µm and at most 50 µm.

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