Composition of polyamide and polar graphene

Abstract

The present invention relates to a composition comprising, at least 50% by weight of the total weight of the composition, at least one polyamide having an intrinsic viscosity greater than 1.2; 0.05% to 20% by weight of polar graphene having an average thickness between 0.5 nm and 75 nm; and 3% to 40% by weight of at least one impact modifier. The present invention also relates to the use of this composition for the preparation of single-layer or multi-layer structures for storing, transporting, and distributing fluids, particularly transport vehicle fluids.

Description

[Technical Field]

[0001] The present invention relates to polyamide and graphene compositions for the manufacture of single-layer or multi-layer structures, particularly for fluid transport, distribution, or storage applications. [Background technology]

[0002] The supply of fluids to transport vehicles, such as automobiles, trains, and trucks, particularly fuel and cooling fluids for internal combustion engine vehicles, and hydrogen for fuel cells, requires storage, distribution, and transport structures such as tanks and pipes. These structures must satisfy the following two important functions: - Leak-proof or low-permeability properties to suppress fluid loss; - Mechanical strength (tensile strength and impact strength). Furthermore, it is essential that the fluid carries little to no contaminants from the storage, distribution, or transport structure. Therefore, it is essential that the extractable content of the composition forming the storage, distribution, or transport structure is as low as possible.

[0003] Therefore, a composition that enables the preparation of structures for storing, distributing and / or transporting fluids, particularly fluids used in transport vehicles, in addition to having good mechanical strength properties, - Low permeability to suppress fluid loss; and / or - Low extractables content There is a genuine need to provide a composition having the following characteristics.

[0004] In addition, - Good fire resistance, in particular, that the structure exhibits fire resistance of V0, V1 or V2 in the UL94 test (IEC60695-11-10); and / or - Good thermal and / or electrical conductivity; and / or - A good balance between low density and good mechanical strength There is also a need to provide compositions for the preparation of fluid storage, distribution, and / or transport structures having [specific properties]. [Overview of the project]

[0005] Firstly, the present invention provides, with respect to the total weight of the composition, - At least 50% by weight of at least one type of polyamide having an intrinsic viscosity greater than 1.2; - 0.05% to 20% by weight of polar graphene; - 3% to 40% by weight of at least one impact modifier This relates to compositions containing the following:

[0006] In particular, preferably, the present invention is based on the total weight of the composition, - At least 50% by weight of at least one type of polyamide having an intrinsic viscosity greater than 1.2; - Polar graphene with an average thickness between 0.5 nm and 75 nm, ranging from 0.05 wt% to 20 wt%; - 3% to 40% by weight of at least one impact modifier This relates to compositions containing the following:

[0007] In one embodiment, polar graphene is graphene oxide, or graphene functionalized with at least one polyamide-reactive functional group, preferably a functional group selected from maleic anhydride, a carboxylic acid, a primary amine, and an isocyanate, preferably maleic anhydride and an amine.

[0008] In one embodiment, the polyamide of the composition according to the present invention is - An aliphatic polyamide, · At least one amino acid from C6 to C18, preferably C9 to C18, more preferably C10 to C18, even more preferably C10 to C12, especially C11; or · At least one lactam from C6 to C18, preferably from C9 to C18, more preferably from C10 to C18, and even more preferably from C10 to C12, especially C12; or • At least one C4-C36, especially C6-C36, preferably C6-C18, preferably C6-C12, more preferably C10-C12 aliphatic diamine Ca and at least one C4-C36, especially C6-C36, preferably C6-C18, preferably C10-C18, more preferably C10-C12 aliphatic diacitate Cb Aliphatic polyamides derived from polycondensation of; or - Semi-aromatic polyamide of formula A / XT (wherein A is selected from units obtained from amino acids, units obtained from lactams, and units corresponding to the formula (Cc diamine)·(Cd diacid), c represents the number of carbon atoms in the diamine, d represents the number of carbon atoms in the diacid, and c and d are between 4 and 36, preferably between 9 and 18, respectively; the (Cc diamine) unit is selected from the linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines described above; the (Cd diacid) unit is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids; XT represents a unit obtained from the polycondensation of Cx diamine and terephthalic acid, x represents the number of carbon atoms in the Cx diamine, x is between 5 and 36, preferably between 9 and 18, and T corresponds to terephthalic acid) That is the case.

[0009] Preferably, the polyamide is - Aliphatic polyamides selected from PA6, PA66, PA11, PA12, PA610, PA612, PA1010, PA1012, and PA1212; - Semi-aromatic polyamides selected from PA MPMDT / 6T, PA11 / 10T, PA 5T / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T, and 11 / 5T / 10T (wherein T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane) is as follows.

[0010] According to one embodiment, the composition preferably contains an aliphatic polyamide that exceeds 50% by weight, preferably exceeds 70% by weight, and more preferably exceeds 85% by weight based on the total weight of the polyamide. Preferably, the composition according to the present invention contains 100% by weight of aliphatic polyamide based on the total weight of the polyamide.

[0011] In one embodiment, the impact modifier is selected from olefin copolymers, particularly copolymers containing ethylene or propylene units.

[0012] The present invention also relates to a single-layer or multi-layer structure, wherein at least one of the layers in the case of a single-layer structure or at least one of the layers in the case of a multi-layer structure is wholly or partially formed from the composition according to the present invention. In one embodiment, these structures are tubular structures. In another embodiment, these structures are tanks.

[0013] The present invention also relates to the use of the above-mentioned structures for the transportation, distribution, and storage of fluids. In one embodiment, the fluid is hydrogen. In another embodiment, the fluid is fuel.

[0014] The present invention also relates to the use of the composition according to the present invention for the production of single-layer or multi-layer structures by injection, extrusion, extrusion blow molding, or rotational molding, preferably by extrusion.

[0015] The present invention also relates to a composition containing at least 50% by weight of at least one polyamide having an intrinsic viscosity exceeding 1.2, optionally at most 5% by weight of at least one additive, optionally at most 40% by weight of at least one impact modifier and / or optionally at most 1% by weight of at least one plasticizer, wherein the percentages are given based on the total weight of the composition. In the composition, 4 g / m 2 Hereinafter, preferably 3 g / m 2This relates to the use of at least one type of polar graphene having an average thickness between 0.5 nm and 75 nm, in an amount ranging from 0.05 wt% to 20 wt%, to obtain the following extractable content.

[0016] The present invention also relates to the use of at least one polar graphene having an average thickness between 0.5 nm and 75 nm in 0.05 wt% to 20 wt% in a composition comprising at least 50 wt% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5 wt% by weight of at least one additive, optionally up to 40 wt% by weight of at least one impact modifier and / or optionally up to 1 wt% by weight of at least one plasticizer, wherein the percentage is given relative to the total weight of the composition, and the percentage is given relative to the total weight of the composition, and the present invention also relates to the use of at least one polar graphene having an average thickness between 0.5 nm and 75 nm, comprising at least 50 wt% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5 wt% by weight of at least one additive, optionally up to 40 wt% by weight of at least one impact modifier and / or optionally up to 1 wt% by weight of at least one plasticizer, wherein the percentage is given relative to the total weight of the composition.

[0017] The present invention also relates to the use of at least one polar graphene having an average thickness between 0.5 nm and 75 nm, in an amount ranging from 0.05 wt% to 20 wt% in a composition comprising at least 50 wt% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5 wt% by weight of at least one additive, optionally up to 40 wt% by weight of at least one impact modifier and / or optionally up to 1 wt% by weight of at least one plasticizer, where the percentages are given relative to the total weight of the composition, to obtain a lower transmittance than that obtained in the same graphene-free composition in which graphene is replaced with the same amount of polyamide.

[0018] The present invention also relates to a method for manufacturing a single-layer or multi-layer structure, characterized by including a step of manufacturing a sealing layer by injection, extrusion, extrusion blow molding, or rotational molding.

[0019] Particularly advantageously, the inventors have shown that a combination of polyamide and graphene can significantly improve the mechanical strength of fluid storage, distribution, and / or transport structures prepared from these compositions while simultaneously suppressing their density.

[0020] Particularly advantageously, the composition according to the invention has a hydrogen permeability of less than 10.00×10 -16 mol.m / m 2 .s.Pa, preferably less than 9.50×10 -16 mol.m / m 2 .s.Pa, measured at atmospheric pressure and 60 °C in accordance with the ISO 15105-2 standard. In addition to this feature, the composition according to the invention preferably provides at least one of the following properties: - An extractable content of less than 4 g / m 2 or less, preferably less than 3 g / m 2 , measured in accordance with the TL52712 standard; - A thermal conductivity exceeding 0.5 W / m.K, preferably exceeding 0.6 W / m.K, measured in accordance with the ASTM D5930-17 standard; - A surface resistivity of less than 10 6 Ω.m, preferably less than 10 4 Ω.m, measured in accordance with the IEC 62631-3-2 (2015) standard; - A tensile modulus between 100 MPa and 3000 MPa, preferably between 800 MPa and 2000 MPa, measured in accordance with the ISO 527 standard after conditioning at 23 °C and 50% relative humidity for 15 days; - An elongation at break exceeding 10%, preferably exceeding 20%, particularly exceeding 100%, measured in accordance with the ISO 527 standard after conditioning at 23 °C and 50% relative humidity for 15 days; - An impact strength at 23 °C exceeding 5 kJ / m 2 , preferably exceeding 8 kJ / m 2 , measured in accordance with the ISO 1791eA standard.

Mode for Carrying Out the Invention

[0021] The present invention will be described in more detail and non-limiting form in the following description. Unless otherwise specified, all percentages are by mass. In this specification, the quantities given for a given species may be applied to that species according to all of its definitions (as referred to herein), including more limited definitions.

[0022] In this invention, relative to the total weight of the composition, - At least 50% by weight of at least one type of polyamide having an intrinsic viscosity greater than 1.2; - 0.05% to 20% by weight of polar graphene; - 3% to 40% by weight of at least one impact modifier This relates to compositions containing the following:

[0023] Preferably, the present invention is expressed in terms of the total weight of the composition, - At least 50% by weight of at least one type of polyamide having an intrinsic viscosity greater than 1.2; - Polar graphene with an average thickness between 0.5 nm and 75 nm, ranging from 0.05 wt% to 20 wt%; - 3% to 40% by weight of at least one impact modifier This relates to compositions containing the following:

[0024] The present invention also relates to a composition comprising, with respect to the total weight of the composition, at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier and / or optionally up to 14% by weight of at least one plasticizer, wherein the composition is 4 g / m² in accordance with TL52712 standard. 2 Preferably 3 g / m 2 The present invention relates to the use of at least one type of polar graphene in an amount ranging from 0.05% to 20% by weight to obtain an extractable content of less than 1.25% by weight.

[0025] Preferably, the present invention also relates to a composition comprising, with respect to the total weight of the composition, at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier and / or optionally up to 14% by weight of at least one plasticizer, in accordance with TL52712 standard, 4 g / m² 2 Preferably 3 g / m 2 The present invention relates to the use of at least one type of polar graphene having an average thickness between 0.5 nm and 75 nm, in an amount ranging from 0.05 wt% to 20 wt%, in order to obtain an extractable content of less than 0.5 wt%.

[0026] The present invention also relates to the use of 0.05% to 20% by weight of polar graphene in a composition comprising, with respect to the total weight of the composition, at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier and / or optionally up to 14% by weight of at least one plasticizer, to obtain a lower extractable content than that obtained in the same graphene-free composition in which graphene is replaced by the same amount of polyamide in the composition.

[0027] Preferably, the present invention relates to the use of at least one polar graphene having an average thickness between 0.5 nm and 75 nm in an amount ranging from 0.05 wt% to 20 wt% of the composition, in order to obtain a lower extractable content than that obtained in the same graphene-free composition in which graphene is replaced with the same amount of polyamide. The composition comprises at least 50 wt% of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5 wt% of at least one additive, optionally up to 40 wt% of at least one impact modifier and / or optionally up to 14 wt% of at least one plasticizer, in a composition comprising40 wt% of at least one impact modifier and / or at least one plasticizer, in a composition comprising at least 50 wt% of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5 wt% of at

[0028] The present invention also relates to the use of 0.05% to 20% by weight of at least one polar graphene in a composition comprising at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier and / or optionally up to 14% by weight of at least one plasticizer, in order to obtain a lower fluid permeability than that obtained in the same graphene-free composition in which graphene is replaced by the same amount of polyamide.

[0029] The present invention relates to the use of at least one polar graphene having an average thickness between 0.5 nm and 75 nm in an amount ranging from 0.05 wt% to 20 wt% of the composition to obtain a lower fluid permeability than that obtained in the same graphene-free composition in which graphene is replaced with the same amount of polyamide. Preferably, the composition comprises at least 50 wt% of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5 wt% of at least one additive, optionally up to 40 wt% of at least one impact modifier and / or optionally up to 14 wt% of at least one plasticizer, with respect to the total weight of the composition.

[0030] [Composition] [polyamide] The composition according to the present invention comprises at least 50% by weight, preferably 70% to 99.5% by weight, and more preferably 90% to 99% by weight, of at least one polyamide. The nomenclature used to define polyamides is described in the ISO 1874-1:2011 standard "Plastics - Polyamide (PA) molding and extrusion materials - Part 1: Nomenclature", particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0031] The polyamide has an intrinsic viscosity greater than 1.2, preferably greater than 1.3, more preferably greater than 1.4, and even more preferably greater than 1.6. The measurement of intrinsic viscosity is performed in m-cresol. This method is well known to those skilled in the art. It conforms to ISO 307:2007, but with modifications to the solvent (m-cresol instead of sulfuric acid), temperature (20°C), and concentration (0.5% by mass).

[0032] The polyamide of the present invention is advantageously suitable for use by injection or extrusion, preferably by extrusion. Polyamides can be homopolyamides, copolyamides, or mixtures thereof.

[0033] Polyamides are semi-crystalline polyamides, which are generally solid at room temperature, soften as the temperature rises, especially after passing their glass transition temperature (Tg), rapidly melt after passing their so-called melting point (Tm), and become solid again when the temperature drops below their crystallization temperature. Tg, Tc (crystallization temperature), and Tm are quantified by differential scanning calorimetry (DSC) in accordance with standards 11357-2:2013 and 11357-3:2013, respectively.

[0034] The number-average molecular weight Mn of the semicrystalline polyamide is preferably in the range of 10,000 to 85,000 g / mol, particularly 10,000 to 60,000 g / mol, preferably 10,000 to 50,000 g / mol, and even more preferably 12,000 to 50,000 g / mol. The number-average molecular weight Mn can be measured by any method known to those skilled in the art, and in particular, the number-average molar mass (Mn) and weight-average molar mass (Mw) are quantified by size exclusion chromatography in accordance with ISO 16014-1:2012, 16014-2:2012, and 16014-3:2012 standards under the following conditions: Equipment: Waters Alliance 2695 equipment Solvent: Hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate. Flow rate: 1ml / min Column temperature: 40℃ Two columns connected in series: 1000 Å PFG and 100 Å PFG (PPS) Sample concentration: 1 g / l (dissolves at ambient temperature in 24 hours) Sample filtration using a syringe fitted with an Acrodisc PTFE filter with a diameter of 25 mm and a pore size of 0.2 μm. Injection volume: 100μl Refractive index detection at 40°C, UV detection at 228nm 1,900,000 to 402 g·mol -1 Calibration according to PMMA standards. The calibration curve is modeled as a 5th-degree polynomial.

[0035] In one embodiment, the polyamide is selected from aliphatic polyamides, semi-aromatic polyamides, and mixtures thereof, and is preferably an aliphatic polyamide. The aliphatic polyamide is At least one amino acid from C6 to C18, preferably C9 to C18, more preferably C10 to C18, even more preferably C10 to C12, especially C11; or At least one lactam from C6 to C18, preferably C9 to C18, more preferably C10 to C18, and even more preferably C10 to C12, especially C12; or At least one C4-C36, especially C6-C36, preferably C6-C18, preferably C6-C12, more preferably C10-C12 aliphatic diamine Ca and at least one C4-C36, especially C6-C36, preferably C6-C18, preferably C10-C18, more preferably C10-C12 aliphatic diacitate Cb It can be derived from the polycondensation of the following.

[0036] C6 to C12 amino acids include, in particular, 6-aminohexanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 10-aminoundecanoic acid, 12-aminododecanoic acid and 11-aminoundecanoic acid, and their derivatives, especially N-heptyl-11-aminoundecanoic acid.

[0037] If the aforementioned at least one semicrystalline aliphatic polyamide is obtained from the polycondensation of at least one amino acid, it may thus contain a single amino acid or several amino acids. Advantageously, the semicrystalline aliphatic polyamide is obtained from the polycondensation of a single amino acid, the amino acid being selected from 11-aminoundecanoic acid and 12-aminododecanoic acid, and preferably 11-aminoundecanoic acid.

[0038] C6 to C12 lactams include, in particular, caprolactam, decanolactam, undecanolactam, or lauryllactam.

[0039] If the aforementioned at least one semicrystalline aliphatic polyamide is obtained from the polycondensation of at least one lactam, it may thus contain a single lactam or several lactams. Advantageously, the at least one semicrystalline aliphatic polyamide is obtained from the polycondensation of a single lactam, the lactam being selected from lauryl lactam and undecanolactam, and preferably lauryl lactam.

[0040] Ca diamine may be linear or branched. Linear is preferable. The aforementioned at least one C4-C36 diamine Ca may be selected from, in particular, butanemethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonameethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine, and 1,18-octadecamethylenediamine, octadecenediamine, eicosanediamine, docosanediamine, and diamines obtained from fatty acids.

[0041] Advantageously, the at least one Ca diamine is a C6-C36 diamine, selected from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonameethylenediamine, 1,10-decamethylenediamine, 2,2,4-trimethylhexanediamine (TMD), 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine, and 1,18-octadecamethylenediamine, octadecenediamine, eicosanediamine, docosanediamine, and diamines obtained from fatty acids.

[0042] The aforementioned at least one Cb C4-C36 dicarboxylic acid can be selected from butanediic acid, pentanediic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, brassic acid, tetradecanediic acid, pentadecanediic acid, hexadecanedioic acid, octadecanediic acid, and diacides obtained from fatty acids. Diacids can be linear or branched. Linear is preferable.

[0043] Preferably, the polyamide according to the present invention has a C / N ratio greater than 6.5, preferably greater than 8, and advantageously greater than 9. Advantageously, the aliphatic polyamide is selected from PA6, PA66, PA11, PA12, PA610, PA612, PA1010, PA1012, and PA1212, preferably PA11, PA12, PA610, PA612, PA1010, PA1012, and PA1212, preferably PA11, PA610, PA1010, PA1012, and PA1212, preferably PA11 and PA12, and preferably PA11.

[0044] The aforementioned semi-aromatic polyamides are, in particular, semi-aromatic polyamides of formula X / YAr as described in EP1505099, and in particular, semi-aromatic polyamides of formula A / XT, where A is selected from units obtained from the amino acids described above, units obtained from the lactams described above, and units corresponding to the formula (Cc diamine)·(Cd diacid), c represents the number of carbon atoms in the diamine, d represents the number of carbon atoms in the diacid, and c and d are between 4 and 36, preferably between 9 and 18, the (Cc diamine) unit is selected from the linear or branched aliphatic diamines, alicyclic diamines and alkyl aromatic diamines described above, and the (Cd diacid) unit is selected from the linear or branched aliphatic diacids, alicyclic diacids and aromatic diacids described above; XT represents a unit obtained from the polycondensation of Cx diamine and terephthalic acid, where x represents the number of carbon atoms in the Cx diamine, and x is between 5 and 36, preferably between 9 and 18, and is a polyamide of formula A / 5T, A / 6T, A / 9T, A / 10T or A / 11T, where A is as described above, and is particularly PA MPMDT / 6T, PA11 / 10T, PA 5T / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T or PA It is a polyamide selected from 11 / 5T / 10T.

[0045] T corresponds to terephthalic acid, MXD to m-xylenediamine, MPMD to methylpentamethylenediamine, and BAC to bis(aminomethyl)cyclohexane. The aforementioned semi-aromatic polyamide may also be a polyamide of formula ZAr, where Z is a unit derived from the polycondensation of at least one of the Ca aliphatic diamines described above, and Ar is an aromatic dicarboxylic acid, particularly terephthalic acid, isophthalic acid, and naphthalene acid.

[0046] In one embodiment, the polyamide is aliphatic and is selected from PA6, PA66, PA11, PA12, PA610, PA612, PA1010, PA1012, and PA1212. In another embodiment, the polyamide is semi-aromatic and is selected from polyamides 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T. Preferably, the semi-aromatic polyamide content is less than 30% by weight relative to the total weight of polyamide in the composition according to the present invention.

[0047] In one embodiment, the polyamide of the composition is pre-washed at least once in a system selected from a polar solvent, particularly methanol, water or vapor, or a mixture thereof. According to a preferred embodiment, the composition contains more than 50% by weight, preferably more than 70% by weight, and more preferably more than 85% by weight, of the total weight of the polyamide, of aliphatic polyamide. Preferably, the composition according to the present invention contains 100% by weight of aliphatic polyamide relative to the total weight of the polyamide.

[0048] [Polar Graphene] The composition of the present invention comprises 0.05% to 20% by weight, preferably 0.1% to 15% by weight, more preferably 0.1% to 5% by weight, even more preferably 0.1% to 2% by weight, preferably 0.1% to 1.75% by weight, more preferably 0.1% to 1.5% by weight, even more preferably 0.1% to 1% by weight, and even more preferably at least one polar graphene between 0.1% and 0.75% by weight. When analyzing graphene contained in a composition, the physicochemical characterization of graphene is performed after calcining the graphene at 600°C for 12 minutes in a sealed crucible placed in a muffle furnace, or after dissolving the matrix and filtering the graphene. Dissolution is preferably carried out at 25°C in metha-cresol or hexafluoroisopropanol.

[0049] The specific surface area is measured according to the BET method described in the ISO 9277:2010 standard.

[0050] The term "polar graphene" refers to graphene that contains atoms other than carbon atoms, that is, graphene that contains carbon atoms and other atoms, such as heteroatoms like O, N, and F.

[0051] Preferably, the polar graphene contains oxygen atoms. Preferably, the polar graphene according to the present invention has a carbon atom content of 99.9% or less, preferably between 55% and 99.5%, advantageously between 65% and 98%, more preferably between 75% and 95%, and even more preferably between 90% and 99.5%, relative to the total number of graphene atoms (excluding hydrogen atoms present in graphene).

[0052] Preferably, the polar graphene according to the present invention has a heteroatom (e.g., O, N, F, etc.) content between 0.1% and 45%.

[0053] Preferably, the polar graphene according to the present invention has an oxygen atom content relative to the total number of graphene atoms (excluding hydrogen atoms present in graphene) between 0.1% and 45%, preferably between 5% and 35%, and more preferably between 0.5% and 10%.

[0054] Preferably, the polar graphene according to the present invention has a nitrogen atom content relative to the total number of graphene atoms (excluding hydrogen atoms present in graphene) between 0.1% and 5%, preferably between 0.1% and 2%, and more preferably between 0.5% and 2%.

[0055] The quantitative determination of the ratios between various atoms present in graphene can be performed by elemental analysis. This method is described in the scientific paper "Preparation and Characterization of Graphene Oxide" by Jianguo Song, Xinzhi Wang, and Chang-Tang Chang, Journal of Nanomaterials, Vol. 2014, Article ID 276143, 6 pages, 2014.

[0056] The specific surface area calculated using the BET method is 20m². 2 / g and 1000m 2 Between / g, preferably 50m 2 / g and 750m 2 It is between / g.

[0057] Polar graphene may be oxidized graphene (graphene oxide) or graphene containing at least one polyamide-reactive functional group, particularly maleic anhydride, carboxylic acids, primary amines and isocyanates, preferably at least one functional group selected from maleic anhydride and amines.

[0058] Polar graphene can also be reduced graphene oxide. This type of graphene is obtained by reduction of graphene oxide, resulting in a decrease in the oxygen content of the graphene. This reduction process can be carried out, for example, thermally (exposure to heat), chemically (in the presence of reducing agents such as sodium borohydride (NaBH4), hydroiodic acid (HI), or hydrazine (N2H4), and / or photochemically (exposure to radiation in the presence of a photocatalyst).

[0059] In one embodiment, the polar graphene comprises one or more functional groups selected from alcohol functional groups, ketone functional groups, carboxylic acid functional groups, and epoxide functional groups. Preferably, the polar graphene comprises at least two, and advantageously at least three, different functional groups selected from alcohol functional groups, ketone functional groups, carboxylic acid functional groups, and epoxide functional groups. The polar graphene preferably has an average thickness between 0.5 nm and 100 nm, preferably between 1 nm and 100 nm, more preferably between 0.5 nm and 75 nm, more preferably between 1 nm and 50 nm, more preferably between 1.5 nm and 50 nm, and more preferably between 2 nm and 25 nm. Polar graphene has a lateral dimension between 0.1 μm and 100 μm, particularly between 0.25 μm and 75 μm, advantageously between 0.4 μm and 50 μm, preferably between 0.5 μm and 40 μm, and more preferably between 0.5 μm and 10 μm.

[0060] The number of layers in graphene can be quantified by X-ray diffraction or atomic force microscopy. For graphene materials with a small number of layers, Raman spectroscopy is preferred. The thickness and dimensions of graphene can also be quantified by optical microscopy, scanning electron microscopy, or transmission electron microscopy. The method for measuring the average thickness and lateral dimensions of graphene is described in the ISO / TS21356-1:2021 standard.

[0061] Advantageously, graphene and polyamide are covalently bonded via amide, ester, urea, or urethane functional groups, preferably amide functional groups.

[0062] Preferably, the composition according to the present invention contains less than 10% by weight, preferably less than 1% by weight, and more preferably less than 0.1% by weight of carbon nanotubes, based on the total weight of the composition. In one embodiment, the composition according to the present invention does not contain carbon nanotubes.

[0063] [Impact modifier] The impact modifier can be present in an amount of up to 40% by weight relative to the total weight of the composition. In one embodiment, the impact modifier is present in an amount of up to 35% by weight of the total weight of the composition, particularly up to 30% by weight of the total weight of the composition, preferably up to 15% by weight of the total weight of the composition, and more preferably up to 12% by weight of the total weight of the composition. In another embodiment, the impact modifier is present in an amount of 3% to 40% by weight, particularly 3% to 35% by weight, especially 3% to 30% by weight, preferably 3% to 15% by weight, for example, 3% to 12% by weight, relative to the total weight of the composition.

[0064] The impact modifier is advantageously composed of a polymer, particularly a polyolefin, having a flexural modulus of less than 100 MPa measured at 23°C and 50% relative humidity RH in accordance with ISO 178:2010, and a Tg of less than 0°C (measured at the inflection point of a DSC thermogram at a heating rate of 20 K / min in accordance with 11357-2:2013).

[0065] In one embodiment, polyether block amide (PEBA) is excluded from the definition of an impact modifier. The polyolefin used as an impact modifier may be functionalized or unfunctionalized, or it may be a mixture of at least one functionalized polyolefin and / or at least one unfunctionalized polyolefin. For simplicity, polyolefins are denoted as (B), and functionalized polyolefins (B1) and unfunctionalized polyolefins (B2) are described below.

[0066] Unfunctionalized polyolefins (B2) are typically homopolymers or copolymers of α-olefins or diolefins, such as ethylene, propylene, 1-butene, 1-octene, and butadiene. Examples include: - Polyethylene homopolymers and copolymers, particularly LDPE, HDPE, LLDPE (linear low-density polyethylene), VLDPE (very low-density polyethylene), and metallocene polyethylene. - Propylene homopolymer or copolymer, - Ethylene / α-olefins, such as ethylene / propylene, EPR (an abbreviation for ethylene-propylene-rubber), and ethylene / propylene / diene (EPDM) copolymers; - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), and styrene / ethylene-propylene / styrene (SEPS) block copolymers; - A copolymer of ethylene and at least one product selected from salts or esters of unsaturated carboxylic acids such as alkyl (meth)acrylates (e.g., methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), wherein the proportion of the comonomer can be up to 40% by weight.

[0067] Functionalized polyolefins (B1) can be polymers of α-olefins having reactive units (functional groups); such reactive units are acids, anhydrides, or epoxy functional groups. Examples include polyolefins (B2) that have been grafted, copolymerized, or tern-copolymerized with unsaturated epoxides such as glycidyl (meth)acrylate, or carboxylic acids or their corresponding salts or esters such as (meth)acrylic acid (the latter of which can be completely or partially neutralized with metals such as Zn), or carboxylic acid anhydrides such as maleic anhydride. Functionalized polyolefins are, for example, PE / EPR blends having a weight ratio that can vary in a wide range, for example, between 40 / 60 and 90 / 10, the blend being co-grafted with anhydrides, particularly maleic anhydride, with graft rates, for example, from 0.01% to 5% by weight.

[0068] The functionalized polyolefin (B1) can be selected from the following (co)polymers grafted with maleic anhydride or glycidyl methacrylate, with grafting rates ranging from, for example, 0.01% to 5% by weight: - Copolymers of PE, PP, ethylene, and propylene, butene, hexene, or octene, for example, containing 35% to 80% by weight of ethylene; - Ethylene / α-olefins, such as ethylene / propylene copolymer, EPR (abbreviation for ethylene propylene rubber), and ethylene / propylene / diene (EPDM) copolymer; - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), and styrene / ethylene-propylene / styrene (SEPS) block copolymers; - A copolymer of ethylene and vinyl acetate (EVA), containing up to 40% by weight of vinyl acetate; - A copolymer of ethylene and alkyl (meth)acrylate, containing up to 40% by weight of alkyl (meth)acrylate; - A copolymer of ethylene, vinyl acetate (EVA), and alkyl (meth)acrylate, containing up to 40% by weight of comonomers.

[0069] The functionalized polyolefin (B1) can also be selected from ethylene / propylene copolymers (products described in EP-A-0342066) which have propylene as the main component, grafted with maleic anhydride, and then condensed with a monoaminopolyamide (or polyamide oligomer).

[0070] Functionalized polyolefin (B1) may also be a copolymer or terpolymer of at least the following units: (1) ethylene, (2) alkyl (meth)acrylate or saturated vinyl carboxylate, and (3) anhydride such as maleic anhydride, or epoxy such as (meth)acrylic acid or glycidyl (meth)acrylate.

[0071] Examples of the latter type of functionalized polyolefin include the following copolymers, where ethylene preferably accounts for at least 60% by weight, and ter monomers (functional groups) account for, for example, 0.1% to 10% by weight of the copolymer: - Ethylene / alkyl (meth)acrylate / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer; - Ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymer; - Ethylene / vinyl acetate or alkyl (meth)acrylate / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer. In the above copolymer, (meth)acrylic acid may be chlorided with Zn or Li.

[0072] In (B1) or (B2), the term "alkyl (meth)acrylate" means C1-C8 alkyl methacrylates and acrylates, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate, and ethyl methacrylate.

[0073] Furthermore, the polyolefin (B1) may be crosslinked by any suitable method or agent (such as a diepoxy, diacid, or peroxide); the term “functionalized polyolefin” also includes mixtures of the polyolefin with a bifunctional reagent such as a diacid, dianhydride, or diepoxy that can react with these polyolefins, or mixtures of at least two functionalized polyolefins that can react with each other. The copolymers (B1) and (B2) described above may be randomly or block copolymerized, and may have a linear or branched structure.

[0074] The molecular weight, MFI index, and density of these polyolefins can also vary widely, as will be understood by those skilled in the art. MFI is an abbreviation for melt flow index, and is measured according to the ASTM 1238 standard.

[0075] Advantageously, non-functionalized polyolefins (B2) are selected from polypropylene homopolymers or copolymers, and ethylene homopolymers or copolymers of ethylene with higher α-olefin type comonomers such as butene, hexene, octene, or 4-methyl-1-pentene. Examples include PP, high-density PE, medium-density PE, low-density linear PE, low-density PE, or ultra-low-density PE. Those skilled in the art know that these polyethylenes can be produced by the "radical" method, "Ziegler" type catalysts, or more recently, "metallocene" catalysts.

[0076] Advantageously, the functionalized polyolefin (B1) is selected from any polymer comprising α-olefin units and units having reactive polar functional groups such as epoxy groups, carboxylic acid groups, or carboxylic acid anhydride functional groups. Examples of such polymers that can be cited include terpolymers of ethylene, alkyl acrylates, and maleic anhydride or glycidyl methacrylate, e.g., Lotader® products (SK Functional Polymers), or polyolefins grafted with maleic anhydride, e.g., Orevac® products (SK Functional Polymers), as well as terpolymers of ethylene, alkyl acrylates, and (meth)acrylic acid. Also cited are polypropylene homopolymers or copolymers obtained by grafting carboxylic acid anhydrides and then condensing them with polyamides or monoaminopolyamide oligomers.

[0077] Preferably, the impact modifier of the present invention is the aforementioned polyolefin, and has a carbon atom content of more than 70%, preferably more than 80%, and more preferably more than 90%, relative to the number of atoms excluding hydrogen atoms in the polyolefin. This carbon content makes it possible to determine a predetermined polarity of the impact modifier. The carbon content of the impact modifier can be measured by any technique known to those skilled in the art, in particular by elemental analysis. Preferably, the impact modifier is selected from olefin copolymers, particularly copolymers containing ethylene or propylene units.

[0078] [Additives] The compositions according to the present invention may also contain at least one additive. The additive may be present in an amount of up to 5% by weight of the total weight of the composition. Accordingly, the compositions according to the present invention contain additives in an amount of 0% to 5% by weight of the total weight of the composition. In one embodiment, the additive is present in an amount of 0.1% to 5% by weight relative to the total weight of the composition of layer (I).

[0079] Additives can be selected from antioxidants, polycondensation catalysts, heat stabilizers, UV absorbers, light stabilizers, lubricants, mineral fillers, flame retardants, nucleating agents, plasticizers, dyes, carbon black, and carbon-based nanofillers. In the context of the present invention, the term "polycondensation catalyst" means a catalyst used in the preparation of polyamides. Preferably, the composition of the present invention contains at least one organic or inorganic stabilizer as an additive, such as a phenolic, phosphite, or copper-based antioxidant.

[0080] In one embodiment, the composition of the present invention may also contain short reinforcing fibers in an amount of 5% to 49% by weight, preferably 5% to 30% by weight, based on the total weight of the composition. The "short" fibers have a length between 100 μm and 400 μm, preferably between 200 μm and 400 μm. These short reinforcing fibers are - Natural fibers - Mineral fibers having a high melting point Tm' that is higher than the melting point Tm of the semicrystalline polyamide of the present invention and higher than the polymerization temperature and / or processing temperature; - Polymer fibers or polymer fibers having a melting point Tm' that is higher than the polymerization temperature or higher than the melting point Tm of the semicrystalline polyamide constituting the matrix of the thermoplastic material, and higher than the processing temperature, or if not Tm', a glass transition temperature Tg'; - or a mixture of the above fibers It can be selected from the following.

[0081] Examples of mineral fibers suitable for use in the present invention include nanotube or carbon nanotube (CNT) fibers, carbon nanofibers, or carbon fibers containing graphene; silica fibers such as E-type, R-type, or S2-type glass fibers in particular; boron fibers; ceramic fibers, particularly silicon carbide fibers, boron carbide fibers, boron carbonitride fibers, silicon nitride fibers, boron nitride fibers, and basalt fibers; fibers or filaments based on metals and / or alloys thereof; metal oxide fibers, particularly alumina (Al2O3) fibers; metallized fibers such as metallized glass fibers and metallized carbon fibers; or mixtures of the aforementioned fibers.

[0082] More specifically, these fibers can be selected as follows: - Mineral fibers may be selected from carbon fibers, carbon nanotube fibers, glass fibers, especially E-type, R-type, or S2-type glass fibers; boron fibers, ceramic fibers, especially silicon carbide fibers, boron carbide fibers, boron carbonitride fibers, silicon nitride fibers, boron nitride fibers, basalt fibers, metal and / or alloy-based fibers or filaments, metal oxide-based fibers such as Al2O3, metallized fibers such as metallized glass fibers and metallized carbon fibers, or mixtures of the above fibers, and - Under the above conditions, polymer fibers or polymer-based fibers are selected from the following: - Thermosetting polymer fibers, more specifically selected from unsaturated polyesters, epoxy resins, vinyl esters, phenolic resins, polyurethanes, cyanoacrylates, and polyimides such as bismaleimide resins, or aminoplasts obtained by the reaction of amines such as melamine with aldehydes such as glyoxal or formaldehyde. - Thermoplastic polymer fibers, more specifically selected from the following: - Polyamide fibers, especially polyphthalamide fibers, - Aramid fibers (such as Kevlar®) and aromatic polyamide fibers, for example, corresponding to one of the formulas: PPD.T, MPD.I, PAA, and PPA, where PPD and MPD are p- and m-phenylenediamine, respectively, PAA is a polyarylamide, and PPA is a polyphthalamide. - Polyamide block copolymer fibers such as polyamide / polyether, polyether ether ketone (PEEK), polyether ketone ketone (PEKK), or polyaryl ether ketone (PAEK) fibers such as polyether ketone ether ketone ketone (PEKEKK).

[0083] Preferred short reinforcing fibers are short fibers selected from metallized carbon fibers, glass fibers including metallized E, R, and S2 types, aramid fibers (such as Kevlar®), or aromatic polyamide fibers, polyether ether ketone (PEEK) fibers, polyether ketone ketone (PEKK) fibers, polyether ketone ether ketone ketone (PEKEKK) fibers, or mixtures thereof.

[0084] Natural fibers can be selected from flax fibers, castor bean fibers, wood fibers, sisal fibers, kenaf fibers, coconut fibers, hemp fibers, and jute fibers. Preferably, the reinforcing fibers present in the composition according to the present invention are selected from glass fibers, carbon fibers, flax fibers, and mixtures thereof, more preferably glass fibers and carbon fibers, and even more preferably glass fibers. Preferably, the composition of the present invention does not contain any continuous fibers.

[0085] In a preferred embodiment, the composition of the present invention does not contain any long reinforcing fibers, i.e., reinforcing fibers longer than 400 μm.

[0086] [Plasticizer] The composition according to the present invention may also contain at least one plasticizer. The plasticizer content in the composition according to the present invention is 0% to 14% by weight of the total weight of the composition. For example, plasticizers are selected from benzenesulfonamide derivatives, such as n-butylbenzenesulfonamide (BBSA); ethyltoluenesulfonamide or N-cyclohexyltoluenesulfonamide; hydroxybenzoic acid esters, such as 2-ethylhexyl p-hydroxybenzoate and 2-hexyldecyl p-hydroxybenzoate; tetrahydrofurfuryl alcohol esters or ethers, such as oligoethyleneoxytetrahydrofurfuryl alcohol; and esters of citric acid or hydroxymalonic acid, such as oligoethyleneoxymalonate. The use of a mixture of plasticizers does not deviate from the scope of the present invention.

[0087] In one embodiment, the plasticizer is present in the composition in an amount of 1% to 14% by weight, particularly 1% to 12% by weight, relative to the total weight of the composition. In another embodiment, the plasticizer is present in an amount of 5% to 14% by weight, particularly 5% to 12% by weight, relative to the total weight of the composition. In a particularly preferred embodiment, the composition contains less than 1% by weight, preferably less than 0.5% by weight, of the plasticizer relative to the total weight of the composition. In a particularly preferred embodiment, the composition of the present invention does not contain any plasticizer.

[0088] Particularly preferred, the present invention is, with respect to the total weight of the composition, - At least 50% by weight of at least one type of polyamide having an intrinsic viscosity greater than 1.2; - Polar graphene with an average thickness between 0.5 nm and 75 nm, ranging from 0.05 wt% to 20 wt%; - 3% to 40% by weight of at least one impact modifier This relates to compositions containing the following:

[0089] [Method for preparing a composition] The present invention also relates to a method for preparing such compositions. In the first embodiment, the method for preparing the composition according to the present invention is as follows: (i) the step of preparing a masterbatch by dispersing graphene in a polyamide matrix; and then (ii) A step of mixing a masterbatch with a polyamide according to the present invention, which contains an optional impact modifier, additives and plasticizers. Includes. Preferably, in step (i), the graphene content is 10% to 50% by weight relative to the weight of the masterbatch.

[0090] Advantageously, the polyamide of the masterbatch is the same as the polyamide of the composition according to the present invention. Preferably, in step (ii), the masterbatch content is between 1% and 20% of the total weight of the mixture obtained in step (ii).

[0091] Preferably, in step (ii), the masterbatch and polyamide are mixed in a molten state. The mixing can be carried out in any apparatus known to those skilled in the art for mixing, kneading, or extruding molten plastics, such as an internal mixer, an open mill, an extruder, such as a single-screw extruder, a counter-rotating or co-rotating twin-screw extruder, a co-kneader, such as a continuous co-kneader, or a stirring reactor. Preferably, the mixing is carried out in an extruder or co-kneader, more preferably in an extruder, and even more preferably in a twin-screw extruder.

[0092] Preferably, the mixing in step (ii) is carried out at a temperature at least 10°C higher than the melting point of the polyamide, preferably at least 20°C higher than the melting point of the polyamide, and more preferably at least 30°C higher than the melting point of the polyamide. Advantageously, the mixing is carried out for a period of 30 seconds to 15 minutes, preferably 40 seconds to 10 minutes. Preferably, the mixing is carried out with stirring.

[0093] Prior to mixing in step (ii), the masterbatch and polyamide may be in the form of powder or granules independently. Advantageously, the preparation method includes a step of forming the mixture obtained in step (ii) into granules or powder. When forming the mixture into powder, it is preferable to first form it into granules or flakes, and then grind the granules or flakes into powder. Any type of mill can be used, such as a hammer mill, pin mill, attrition disc mill, or impact classifier mill.

[0094] In another embodiment, the compositions according to the present invention can preferably be prepared in a single step by dispersing graphene in a polyamide according to the present invention in a molten material, preferably in the optional presence of additives, impact modifiers, and / or plasticizers. In this embodiment, the preparation method includes a step of forming the obtained mixture into granules or powder. When forming the mixture into powder, it is preferable to first form it into granules or flakes, and then crush the granules or flakes to make a powder. Any type of mill can be used, such as a hammer mill, pin mill, attrition disc mill, or impact classifier mill. This second embodiment of the method is undesirable because the small size of the graphene particles poses health risks (particularly inhalation).

[0095] Preferably, the compositions according to the present invention cannot be obtained by polymerization of polyamides in the presence of graphene. Specifically, such a process is undesirable for environmental and economic reasons because it requires a large amount of solvent. Furthermore, the use of graphene in the polymerization reactor contaminates the reactor.

[0096] [Single-layer or multi-layer structure] The present invention also relates to a single-layer or multilayer structure in which, in the case of a single-layer structure, a layer, or in the case of a multilayer structure, at least one layer, is formed entirely or partially from the composition according to the present invention, preferably consisting of the composition according to the present invention. The structures according to the present invention are preferably intended for the transport, storage, and / or distribution of fluids, particularly for transport vehicles, particularly automobiles, and other transport vehicles such as trains, trucks, and subways. The term "automobile" refers to any vehicle that is powered by an internal combustion engine, electric motor, or hybrid motor and has wheels or caterpillar tracks, but does not include aircraft. Automobiles can be two-wheeled vehicles, three-wheeled vehicles, four-wheeled vehicles, or tracked vehicles. For example, you can choose from electric bicycles, mopeds, motorcycles, sidecars, passenger cars, vans, tractors, trucks, buses, large buses, snowmobiles, auto chenilles, bulldozers, snow groomers, and tanks. In particular, you can choose from passenger cars, vans, trucks, buses, and large buses.

[0097] The single-layer or multi-layer structures of the present invention may be tanks, pipes (or tubes), or liners. Throughout this specification, the terms “tube” or “pipe” may be used, and these refer to the same thing.

[0098] In one embodiment, the present invention relates to a single-layer or multi-layer structure, such as a tank for fluid storage, which includes at least one layer obtained using the composition of the present invention, preferably at least one of which layers is made of the composition according to the present invention. In another embodiment, the present invention relates to a single-layer or multi-layer tubular (MLT) structure for fluid transport and distribution, comprising, preferably, at least one layer obtained using the composition of the present invention. Preferably, the multilayer structure includes at least one other layer, preferably containing polyamide.

[0099] The multilayer structure (MLT or tank) according to the present invention comprises at least one layer obtained from the composition of the present invention, preferably a layer made of the composition of the present invention (preferably this layer is the innermost layer (in contact with the fluid)), and one or more other layers selected from the group consisting of, for example, a reinforcing layer (particularly a composite layer), a sealing layer (barrier layer), a chemical-resistant layer, a burst strength layer, and the like. These multilayer structures are well known to those skilled in the art.

[0100] The term "fluid" refers particularly to gases used in automobiles, or particularly to liquids used in the automotive sector. Examples of liquids include oil, brake fluid, urea solution, glycol-based coolants, fuels, particularly gasoline, diesel, LPG, bio-gasoline or biodiesel, and more specifically, alcohol-blended gasoline. The fluid according to the present invention may also be hydrogen. In a preferred embodiment, air, nitrogen, and oxygen are excluded from the definition of the fluid. In one embodiment, the fluid refers to fuel, in particular gasoline, and in particular alcohol-blended gasoline. In another embodiment, the fluid refers to hydrogen.

[0101] The term "gasoline" refers to a mixture of hydrocarbons obtained from the distillation of petroleum, to which additives or alcohols, such as methanol and ethanol, may be added, and in some cases alcohol may be the main component. The term "alcohol-blended gasoline" refers to gasoline to which methanol or ethanol has been added. It also refers to E95 type gasoline that does not contain petroleum distillation-derived products.

[0102] In the present invention, the tank may be a tank for mobile storage of hydrogen, i.e., a tank mounted on a truck for transporting hydrogen, an automobile for transporting hydrogen and supplying hydrogen to a fuel cell, such as a train for supplying hydrogen, or a drone for supplying hydrogen, or it may be a stationary storage tank for hydrogen at a station for distributing hydrogen to vehicles. The tank may also be a fuel or coolant storage tank.

[0103] In one embodiment, the multilayer structure according to the present invention may be, for example, a hydrogen tank, and may include or consist of several layers, particularly two layers, excluding a film or granules. Generally, a hydrogen tank includes at least one barrier layer (or sealing layer) and one reinforcing layer. A hydrogen tank may include, for example, several sealing layers and several reinforcing layers, or one sealing layer and several reinforcing layers, or several sealing layers and one reinforcing layer, or one sealing layer and one reinforcing layer, or consist of these.

[0104] The term "barrier layer" (or "sealing layer") refers to a layer that has low permeability and good resistance to various components of a fluid, particularly fuel and hydrogen. In other words, a barrier layer slows down the permeation of a fluid, especially fuel (both its polar components (such as ethanol) and its non-polar components (hydrocarbons)) or hydrogen, to other layers of a structure, or even to the outside of the structure. Therefore, a barrier layer is, among other things, a layer that prevents loss into the atmosphere due to the diffusion of excess gasoline, and thus avoids air pollution.

[0105] Therefore, the present invention preferably, - A single-layer or multi-layer tubular structure for transporting, distributing, or storing fluids, comprising at least one layer, preferably an inner layer, and preferably comprising at least one layer, preferably an inner layer, made of the composition according to the present invention; - A single-layer tubular structure for transporting, distributing, or storing a fluid, formed entirely or partially from a composition according to the present invention, preferably a single-layer tubular structure made of a composition according to the present invention; - A multilayer tubular structure for transporting, distributing, or storing fluids, comprising at least one layer, preferably an inner layer, formed entirely or partially from the composition according to the present invention, and preferably comprising at least one layer, preferably an inner layer, and at least one other layer, preferably another layer comprising polyamide; - A single-layer or multi-layer tank for transporting or storing fluids, which is entirely or partially formed from the composition according to the present invention and comprises at least one layer, preferably an inner layer, preferably comprising at least one layer, preferably an inner layer, made of the composition according to the present invention; - A single-layer tank for transporting or storing fluids, formed entirely or partially from a composition according to the present invention; preferably a single-layer tank made of a composition according to the present invention; - A multilayer tank for transporting or storing fluids, comprising at least one layer, preferably an inner layer, which is entirely or partially formed from the composition according to the present invention, and at least one other layer, preferably an inner layer, which is made of the composition according to the present invention, and at least one other layer, which is made of polyamide. Regarding.

[0106] In one embodiment, the structure of the present invention can be used for transporting, distributing, and storing hydrogen (H2). In another embodiment, the structure of the present invention may be used for transporting, distributing, and storing coolants. In another embodiment, the structure of the present invention may be used for transporting, distributing, and storing fuel.

[0107] The present invention also relates to a method for preparing a single-layer or multilayer structure as described above, comprising the step of manufacturing a sealing layer by injection, extrusion, extrusion blow molding or rotational molding using a composition according to the present invention. In one embodiment, the structure is a multilayer structure and further includes the step of filament winding the reinforcing layer described above around the sealing layer described above.

[0108] [Use of composition] The present invention also relates to the use of the compositions according to the present invention for the manufacture of single-layer or multilayer structures as described above. The single-layer or multilayer structure is preferably obtained by a step of preparing at least one layer containing the compositions according to the present invention by injection, extrusion, extrusion blow, or rotational molding using the compositions of the present invention. Other layers may be present, and in particular may be formed simultaneously.

[0109] [Graphene used] The present invention also relates to a composition comprising at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier, and / or optionally up to 14% by weight of at least one plasticizer, preferably less than 1% by weight of a plasticizer, more preferably less than 0.1% by weight of a plasticizer, and preferably without a plasticizer, wherein the percentage is given relative to the total weight of the composition, and the composition is 4 g / m 2 Preferably 3 g / m 2 The present invention relates to the use of at least one polar graphene having an average thickness between 0.5 nm and 100 nm, preferably between 1 nm and 100 nm, preferably between 0.5 nm and 75 nm, preferably between 1 nm and 50 nm, preferably between 1.5 nm and 50 nm, and more preferably between 2 nm and 25 nm, in an extractable content of the following: 0.05% to 20% by weight, preferably 0.1% to 15% by weight, more preferably 0.1% to 5% by weight, even more preferably 0.1% to 2% by weight, preferably 0.1% to 1.75% by weight, more preferably 0.1% to 1.5% by weight, even more preferably 0.1% to 0.75% by weight.

[0110] According to a preferred embodiment, the composition contains more than 50% by weight, preferably more than 70% by weight, and more preferably more than 85% by weight, of the total weight of the polyamide, of aliphatic polyamide. Preferably, the composition according to the present invention contains 100% by weight of aliphatic polyamide relative to the total weight of the polyamide.

[0111] The present invention also relates to a composition comprising at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier, and / or optionally up to 14% by weight of at least one plasticizer, preferably less than 1% by weight of plasticizer, more preferably less than 0.1% by weight of plasticizer, and preferably without plasticizer, wherein the percentage given is relative to the total weight of the composition, and the extractable content is 0.05% to 20% by weight, The present invention relates to the use of at least one polar graphene having an average thickness between 0.5 nm and 100 nm, preferably between 1 nm and 100 nm, preferably between 0.5 nm and 75 nm, preferably between 1 nm and 50 nm, preferably between 1.5 nm and 50 nm, preferably between 1.5 nm and 50 nm, and more preferably between 2 nm and 25 nm, preferably in an amount of 0.1% to 15% by weight, more preferably between 0.1% to 5% by weight, more preferably between 0.1% to 2% by weight, preferably between 0.1% to 1.75% by weight, more preferably between 0.1% to 1.5% by weight, more preferably between 0.1% to 1.5% by weight, more preferably between 0.1% to 0.75% by weight. In the context of the present invention, the term “same graphene-free composition” means a comparative composition in which graphene is replaced with the same amount of polyamide, given that all other conditions are the same. If the composition according to the present invention contains a polyamide mixture, it should be understood that the polyamide replacing graphene in the comparative composition is the same polyamide mixture as in the composition according to the present invention in the same relative proportions.

[0112] Preferably, the composition contains more than 50% by weight, preferably more than 70% by weight, and more preferably more than 85% by weight, of the total weight of the polyamide, of aliphatic polyamide. Preferably, the composition according to the present invention contains 100% by weight of aliphatic polyamide relative to the total weight of the polyamide.

[0113] In one embodiment, the extractable content is quantified by a test in which a tubular structure is filled with FAM-B type alcohol-mixed gasoline, the entire structure is heated at 60°C for 96 hours, and then the tube is filtered into a beaker to empty it. The extractable content per unit of the inner surface area of ​​the tube is then obtained by evaporating the beaker filtrate at room temperature and weighing the residue. This measurement method is specifically described in the TL52712 standard.

[0114] Alcohol-blended gasoline FAM B is described in standards DIN 51604-1:1982, DIN 51604-2:1984, and DIN 51604-3:1984. Briefly, alcohol-blended gasoline FAM A is first prepared from a mixture of 50% toluene, 30% isooctane, 15% diisobutylene, and 5% ethanol, and then FAM B is prepared by mixing 84.5% of FAM A with 15% methanol and 0.5% water. FAM B consists of a total of 42.3% toluene, 25.4% isooctane, 12.7% diisobutylene, 4.2% ethanol, 15% methanol, and 0.5% water.

[0115] The term "extractable components" is intended to refer to all compounds that can be removed by a fluid, derived from a composition forming a single-layer or multi-layer structure. Examples of extractable components include plasticizers, monomers, oligomers, and additives. The extractable content is measured in accordance with the TL52712 standard. Preferably, by using the composition according to the present invention, 4 g.m -2 The following is preferably 3 g.m -2 The following extractable content can be achieved.

[0116] The present invention also relates to a composition comprising at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier, and / or optionally up to 14% by weight of at least one plasticizer, preferably less than 1% by weight of a plasticizer, more preferably less than 0.1% by weight of a plasticizer, wherein the percentage is given relative to the total weight of the composition, and the amount of plasticizer is 0.05% to 20% by weight, preferably, to obtain a lower transmittance than that obtained with the same graphene-free composition. The present invention relates to the use of at least one type of polar graphene having an average thickness between 0.5 nm and 100 nm, preferably between 1 nm and 100 nm, more preferably between 0.5 nm and 75 nm, more preferably between 1 nm and 50 nm, more preferably between 1.5 nm and 50 nm, more preferably between 1.5 nm and 50 nm, more preferably between 2 nm and 25 nm, in an amount of 0.1% to 15% by weight, more preferably between 0.1% to 5% by weight, more preferably between 0.1% to 2% by weight, preferably between 0.1% to 1.75% by weight, more preferably between 0.1% to 1.5% by weight, more preferably between 0.1% to 1% by weight, more preferably between 0.1% to 0.75% by weight, with an average thickness between 0.5 nm and 100 nm, preferably between 1 nm and 100 nm, more preferably between 0.5 nm and 75 nm, more preferably between 1 nm and 50 nm, more preferably between 1.5 nm and 50 nm, more preferably between 2 nm and 25 nm. In the context of the present invention, the term “same graphene-free composition” means a comparative composition in which graphene is replaced with the same amount of polyamide, given that all other conditions are the same. If the composition according to the present invention contains a polyamide mixture, it should be understood that the polyamide replacing graphene in the comparative composition is the same polyamide mixture as in the composition according to the present invention in the same relative proportions.

[0117] According to a preferred embodiment, the composition preferably contains more than 50% by weight, preferably more than 70% by weight, and more preferably more than 85% by weight of aliphatic polyamide, based on the total weight of the polyamide. Preferably, the composition according to the present invention contains 100% by weight of aliphatic polyamide based on the total weight of the polyamide.

[0118] The permeability according to the present invention is the permeability of a single-layer or multi-layer structure to a fluid. In certain embodiments, the measured transmittance is hydrogen transmittance, measured at atmospheric pressure and 60°C in accordance with ISO 15105-2. Preferably, the hydrogen transmittance measured at atmospheric pressure and 60°C in accordance with ISO 15105-2 is 10.00 × 10⁻⁶. -16 mol.m / m 2 The pressure is less than 0.sPa, preferably 9.50 × 10⁻⁶. -16 mol.m / m 2 It is less than .s.Pa. The definitions and content of polyamides, graphene, impact modifiers, plasticizers, and additives described above also apply.

[0119] Therefore, the single-layer or multilayer structure of the present invention has good permeability, particularly hydrogen permeability, and a low extractable content.

[0120] [Recyclable] In a particularly advantageous way, structures obtained using the compositions of the present invention are recyclable. The term "recyclable" means that the single-layer or multi-layer structure can be reused after use, and therefore after the transport, distribution, or storage of fluids, and especially after crushing, i.e., particularly by extrusion, while obtaining good mechanical properties, particularly low-temperature impact strength, high burst strength, and high elongation at break, unlike the recycling of graphene-free structures, in the process of manufacturing parts, particularly new single-layer or multi-layer structures. In the context of the present invention, the term "same graphene-free composition" means a comparative composition in which, all other conditions are the same, graphene is replaced by the same amount of polyamide. If the composition according to the present invention contains a polyamide mixture, it should be understood that the polyamide replacing graphene in the comparative composition is the same polyamide mixture as in the composition according to the present invention in the same relative proportions.

[0121] Grinding is carried out to a size ranging from 1 mm to 2 cm, according to common techniques used by those skilled in the art. The reuse of the used tubular structure may be carried out by mixing it with virgin material or by not mixing it. [Examples]

[0122] Unless otherwise stated, percentages are expressed on a weight basis relative to the total weight of the composition. The compositions listed in Table 1 were prepared by compounding under the following conditions: The compositions were manufactured using a ZSK 40mm twin-screw extruder (Coperion). The barrel temperature was set to 280°C, the screw speed to 300 rpm, and the flow rate to 60 kg / h. All materials were introduced into the main hopper at screw start-up.

[0123] The PA11 used is a phosphate-catalyzed polyamide 11 having an acid chain terminal concentration of 30 μeq / g and an amine chain terminal concentration of 33 μeq / g. The PPA used was PPA MXD10, which has an acid chain terminal concentration of 72 μeq / g and an amine chain terminal concentration of 17 μeq / g. The impact modifier is Tafmer MH5020C, sold by Mitsui Chemicals, Inc.

[0124] Graphene 1 is a non-polar graphene with an average thickness of 2 nm and an average lateral dimension of 980 nm. Graphene 1 is not graphene oxide. Graphene 2 is a polar graphene composed of 99 mol% carbon atoms, with an average thickness of 102 nm and an average transverse dimension of 1050 nm. Graphene 3 is reduced graphene oxide containing 6 mol% oxygen atoms relative to carbon atoms, with an average thickness of 1.6 nm and an average transverse dimension of 2300 nm. Graphene 4 is a type of graphene that contains 1 mol% nitrogen atoms relative to carbon atoms, has an average thickness of 1 nm, and an average transverse dimension of 4300 nm.

[0125] Graphene was added in the form of a masterbatch containing 10% by weight of graphene and 90% polyamide (PA11 or PPA). The organic stabilizer used is a mixture consisting of 80% Irganox® 1010 and 20% Irgafos® 168 from BASF. [Table 1]

[0126] Liners with a thickness of 2 mm for the comparative composition and the composition of the present invention were prepared by blow molding. A 100 × 100 × 2 mm plate cut from the prepared liner was tested, and the hydrogen permeability was measured at atmospheric pressure and 60°C in accordance with ISO 15105-2 standard. This test involves sweeping the upper surface of the film with a test gas (hydrogen) and measuring the diffusion flow on the lower surface of the film, which has been swept by a carrier gas (nitrogen), using gas chromatography. The measurement is performed in accordance with the ISO 15105-2 standard. The experimental conditions are shown in Table 2 below. [Table 2]

[0127] 1A test specimens (compliant with ISO 527) and impact test specimens (compliant with ISO 179) were manufactured by injection molding using an unpolished mold with a Battenfeld BA800 CDC press. The following parameters were applied during injection molding of the PA11-containing composition: - Barrel temperature: 250℃ - Nozzle temperature: 270℃ - Mold temperature: 40℃ - Cycle time: 60 seconds

[0128] During injection molding of the composition containing MXD10 (Comparative Example 3), the following parameters were applied: - Barrel temperature: 300℃ - Nozzle temperature: 320℃ - Mold temperature: 60℃ - Cycle time: 60 seconds

[0129] Elongation at break was measured at 23°C using a 1A test specimen in accordance with ISO 527 standards. Impact resistance at 23°C was measured in accordance with ISO 179 1eA standards. Elongation at break and impact strength were measured after 15 days of adjustment at 23°C and 50% relative humidity.

[0130] The results are shown in Table 3. [Table 3] The composition of the present invention provides a better balance between hydrogen barrier properties and mechanical properties (elongation at break and impact strength). Example 1 of the present invention provides a transmittance close to that of Comparative Example 1 while simultaneously significantly improving impact strength. Example 2 of the present invention provides improved transmittance while simultaneously maintaining the level of mechanical properties.

Claims

1. In relation to the total weight of the composition, - At least 50% by weight of at least one type of polyamide having an intrinsic viscosity greater than 1.2; - Polar graphene with an average thickness between 0.5 nm and 75 nm, in a concentration of 0.05 wt% to 20 wt%; - At least one impact modifier in an amount of 3% to 40% by weight. A composition containing the following:

2. - At least one additive in a maximum of 5% by weight; and / or - At least one plasticizer in less than 1% by weight; and / or - 5% to 49% by weight of short reinforcing fibers The composition according to claim 1, further comprising:

3. The composition according to claim 1 or 2, wherein the polar graphene is graphene oxide, or graphene functionalized with at least one polyamide-reactive functional group, preferably a functional group selected from maleic anhydride, a carboxylic acid, a primary amine, and an isocyanate, preferably maleic anhydride and an amine.

4. The composition according to any one of claims 1 to 3, wherein the polar graphene has an oxygen atom content between 0.1% and 45%, preferably between 0.5% and 10%, relative to the total number of atoms in the graphene, excluding the hydrogen atoms present in the graphene.

5. Polyamide, - At least one amino acid from C6 to C18, preferably from C9 to C18, more preferably from C10 to C18, and even more preferably from C10 to C12, especially C11; or - At least one lactam from C6 to C18, preferably from C9 to C18, more preferably from C10 to C18, and even more preferably from C10 to C12, especially C12; or - At least one C4-C36, particularly C6-C36, preferably C6-C18, preferably C6-C12, more preferably C10-C12 aliphatic diamine Ca and at least one C4-C36, particularly C6-C36, preferably C6-C18, preferably C10-C18, more preferably C10-C12 aliphatic diacitate Cb Aliphatic polyamides derived from polycondensation of; or Semi-aromatic polyamide of formula A / XT (wherein A is selected from units obtained from amino acids, units obtained from lactams, and units corresponding to formulas (Cc diamine) and (Cd diacid), c represents the number of carbon atoms in the diamine, d represents the number of carbon atoms in the diacid, and c and d are between 4 and 36, preferably between 9 and 18, the (Cc diamine) unit is selected from the linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines described above, and the (Cd diacid) unit is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids; X.T represents a unit obtained from the polycondensation of Cx diamine and terephthalic acid, x represents the number of carbon atoms in the Cx diamine, x is between 5 and 36, preferably between 9 and 18, and T corresponds to terephthalic acid) The composition according to any one of claims 1 to 4.

6. Polyamide, - Aliphatic polyamides selected from PA6, PA66, PA11, PA12, PA610, PA612, PA1010, PA1012, and PA1212; - Semi-aromatic polyamides selected from PA MPMDT / 6T, PA11 / 10T, PA 5T / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T and 11 / 5T / 10T (wherein T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane) The composition according to any one of claims 1 to 5.

7. With respect to the total weight of the polyamide, - At least 50% by weight, preferably at least 70% by weight, and more preferably at least 85% by weight of aliphatic polyamide A composition according to any one of claims 1 to 6, comprising

8. The composition according to any one of claims 1 to 7, wherein the graphene content is between 0.1% by weight and 1.75% by weight of the total weight of the composition.

9. The composition according to any one of claims 1 to 8, wherein the impact modifier is selected from olefin copolymers, particularly copolymers containing ethylene or propylene units.

10. A single-layer or multi-layer structure, wherein at least one of the layers in the case of a single-layer structure, or at least one of the layers in the case of a multi-layer structure, is formed entirely or partially from the composition described in any one of claims 1 to 9.

11. The structure according to claim 10, characterized in that it is a tubular structure.

12. The structure according to claim 10, characterized in that it is a tank.

13. Use of the structure according to any one of claims 10 to 12 for transporting, distributing and storing fluids.

14. The use according to claim 13, wherein the fluid is hydrogen.

15. The use according to claim 13, wherein the fluid is a coolant.

16. The use according to claim 13, wherein the fluid is fuel.

17. Use of the composition according to any one of claims 1 to 9 for the manufacture of a single-layer or multi-layer structure by injection, extrusion, extrusion blow molding or rotational molding, preferably by extrusion.

18. 1. A composition comprising at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier and / or less than 1% by weight of at least one plasticizer, wherein the percentage is given relative to the total weight of the composition, and the concentration is 4 g / m ２ Preferably 3 g / m ２ Use of at least one type of polar graphene having an average thickness between 0.5 nm and 75 nm, in an amount ranging from 0.05 wt% to 20 wt% to obtain the following extractable content.

19. 1. Use of at least one polar graphene having an average thickness between 0.5 nm and 75 nm, in an amount of 0.05 wt% to 20 wt%, to obtain a lower extractable content than that obtained in the same graphene-free composition in which graphene is replaced by the same amount of polyamide, in a composition comprising at least 50 wt% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5 wt% by weight of at least one additive, optionally up to 40 wt% by weight of at least one impact modifier and / or less than 1 wt% by weight of at least one plasticizer, wherein the percentage is given relative to the total weight of the composition.

20. 1. Use of 0.05% to 20% by weight of at least one polar graphene having an average thickness between 0.5 nm and 75 nm, in a composition comprising at least 50% by weight of at least one polyamide having an intrinsic viscosity greater than 1.2, optionally up to 5% by weight of at least one additive, optionally up to 40% by weight of at least one impact modifier and / or optionally less than 1% by weight of at least one plasticizer, wherein the percentage is given relative to the total weight of the composition, to obtain a lower transmittance than that obtained in the same graphene-free composition in which graphene is replaced with the same amount of polyamide.

21. A method for manufacturing a single-layer or multilayer structure according to any one of claims 10 to 12, characterized by comprising the step of manufacturing a sealing layer by injection molding, extrusion, extrusion blow molding, or rotational molding.

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