WO2017093650A1 - Composition of or for composite material, method for producing a paek composite material from said composition and paek composite material - Google Patents

Abstract

The invention relates to a composition for composite material or composition of composite material, of polyaryletherketone (PAEK) type, said composition being characterised in that it comprises at least one reactive prepolymer, of formula X-(EKKE)-X and/or X-(PAEK)-X with a degree of polymerisation n such that 1 ≤ n ≤ 15 and preferably 2 ≤ n ≤10, where X represents two identical reactive terminal functional groups, each carrying a benzoyl group or a terminal phenoxy group, the functional groups X being capable of reacting together or with a chain extender by addition reactions.

Description

 COMPOSITION OF COMPOSITE MATERIAL, PROCESS FOR PRODUCING PAEK-TYPE COMPOSITE MATERIAL FROM THE SAME, AND PAEK-TYPE COMPOSITE MATERIAL

[Technical area! The invention relates to the field of composite materials including composite materials based thermostable polymers belonging to the family of poly (aryl-ether-ketone) (PAEK).

More particularly, the invention relates to a precursor composition, with or without fibrous reinforcements, a composite material whose matrix is a thermostable polymer of the PAEK family, a method of manufacturing such a composite material PAEK type to from said precursor composition and a mechanical part or a structural element made of composite material of PAEK type obtained according to said manufacturing method.

[Prior Art] Poly (aryl-ether-ketones) (PAEK) are thermoplastic polymers of very high performance and in particular have high thermomechanical properties. They consist of aromatic rings linked by an oxygen atom (ether) and / or by a carbonyl group (ketone). Their properties depend mainly on the ether / ketone ratio. In the abovementioned abbreviations, E denotes an ether function and K denotes a ketone function. In the rest of the document, these abbreviations will be used instead of the usual names to designate the compounds to which they relate.

Poly (aryl-ether-ketones) are used for demanding applications in temperature and / or mechanical stresses, even chemical. PAEK are thermostable thermoplastic polymers whose exceptional properties give them a particular interest in aeronautics and space, but also in the fields of automobile, railway, marine, wind, sports, building, electronics or medical implants. [0005] Because of these exceptional properties, solutions are currently being sought to develop means for implementing materials. High performance composites with matrices belonging to the PAEK family.

However, current processes for manufacturing thermoplastic matrix composites are restrictive and the quality of the composite manufactured is not always optimal. The essential limiting factor for the implementation of a thermoplastic composite is the viscosity of the thermoplastic polymer which will be used as a matrix to coat or to impregnate a fibrous reinforcement. Indeed, even in the molten state, the viscosity of a thermoplastic polymer remains high and thus makes the coating or impregnation of a fibrous reinforcement difficult. When reinforcing fibers are incorporated into the thermoplastic matrix in the molten state, the latter must coat them correctly and the fibers must be homogeneously distributed in the matrix in order to allow the transmission to the reinforcing fibers of the constraints. mechanical properties of the final composite material. Similarly, when the polymer matrix is used to impregnate a fibrous substrate, the impregnation must be satisfactory to allow the transmission to the reinforcing fibers mechanical stresses experienced by the final composite material. In addition, the coating or coating of reinforcing fibers with such a matrix provides chemical protection of these fibers. In particular, for a thermoplastic matrix composite to have good mechanical properties at the end use, especially in terms of impact resistance, it is necessary that the molecular weight of the thermoplastic polymer of the matrix is as high as possible. The mechanical properties of polymers belonging to the PAEK family are also driven by their molecular weight. However, the necessary molecular weights associated with the rigidity of the chains result in very high viscosities of these polymers in the molten state. These viscosities can be between 100 and 3000 Pa.s in the molten state and preferably between 150 and 1500 Pa.s. These high viscosities complicate the use of these polymers as a matrix for the composites and pose serious difficulties in achieving proper embedding or impregnation of the reinforcing fibers. The final composite material obtained can then have defects in coating or impregnation with the appearance of micro-voids for example, which are likely to cause mechanical deficiencies and weaken the final composite material.

The materials based on PAEK are generally shaped by injection molding, extrusion of granules or by laser sintering of the polymer in powder form, for example. When implemented by injection molding for example, the operating temperature is greater than 320 ° C and the holding pressure is generally between 50 and 100MPa. Such parameters are incompatible with conventional methods of manufacturing composite materials. The high viscosities of the polymers belonging to the PAEK family therefore do not make it possible to use them in processes for manufacturing composite materials, conventionally used with thermosetting polymers, such as, for example, the resin transfer molding process ( RTM), injection-reaction molding (RIM), reinforced reaction injection molding (R-RIM), structural injection-reaction molding, (S-RIM), compression injection, pultrusion or even infusion, because it is difficult, if not impossible, to obtain a composite material with a coating or impregnation of good quality reinforcing fibers.

It therefore appears necessary to adapt the synthetic routes PAEK type materials, to make them compatible with conventional methods of manufacturing composite materials. In particular, the viscosity of the matrix must be sufficiently small to be able to coat or impregnate the fibrous reinforcement correctly and the polymerization must preferably be carried out without condensation or solvent in order to avoid the appearance of porosities due to the molecules of gas escaping at the time of polymerization and weakening the final material.

[001 1] Solutions have been considered to overcome the problem of impregnation of fibrous reinforcements by thermoplastic materials.

WO 2014064375 discloses a composition for a thermoplastic composite material or a composition of thermoplastic composite material, the thermoplastic matrix polymer being a semi-crystalline polyamide, the composition being a precursor composition of the polyamide of constitution of the matrix and comprising a mixture of reactive polyamide prepolymers with amine and / or acid chain ends.

US 4638037, meanwhile, describes a method for increasing the molecular weight of PAEK, while retaining its crystalline properties. For this, the method comprises introducing a group I or II alkali metal salt into the composition. When the PAEK and salt composition is heated to a temperature above the melting temperature of the polymer, the molecular weight of the latter increases. The use of salt, however, contaminates the polymer, so that further purification is required to reduce the level of salt in the polymer and the process remains difficult to control.

Document US 2012259086 describes the synthesis of PAEK macrocycles by aromatic nucleophilic substitution and cyclo-depolymerization, as well as the synthesis of PEEK polymers by ring opening polymerization (ROP) from these macrocycles, catalyzed by cesium fluoride. The viscosity of these macrocycles must be relatively low, on the order of 1 Pa.s or lower, if one refers to their composition, thus allowing a good impregnation of fibers and a facilitated implementation of the material. On the other hand, the synthesis of such macrocycles requires either conditions of very high dilution, in order to promote reactions of the reagent on itself, or conditions of pseudo-dilution by very slow additions of the reagent in the reaction medium to guarantee a low and regular concentration in extremities that have not yet reacted. In the first case, the use of a large amount of solvent is to be avoided both economically and industrially and environmentally. In the second case, the pseudo-dilution times are not very compatible with a production on an industrial scale. Finally, one often obtains a mixture of several macrocycles of different sizes (each comprising between 2 and 8 units), and yields that can be relatively low. The isolation of one or more sizes of molecules further lengthens the production time.

[Technical problem] [0015] The object of the invention is therefore to remedy at least one of the disadvantages of the prior art. In particular, the object of the invention is to propose a composition of composite material, or composition for composite material of the PAEK type, the composition having a sufficiently low viscosity, typically less than or equal to 100 Pa.s, preferably less than or equal to 50 Pa.s, and even more preferably between 0.1 and 10 Pa.s, and allowing a new route post-injection synthesis, without condensation or solvent, of thermostable composite materials of the PAEK type, having good thermomechanical properties.

Such a composition should allow to obtain a good compromise between a good coating and a good fiber distribution or good impregnation of a fibrous substrate and a final composite material PAEK type having good thermomechanical properties.

The chemistry of this composition, intended to form the matrix of the final composite material, will also have a fast polymerization kinetics, that is to say compatible with industrial processes, and be compatible with a manufacturing process. final composite material, particularly in a closed mold, such as resin transfer molding (RTM), reaction injection molding (RIM), reinforced reaction injection molding (R-RIM), structural molding by injection-reaction (S-RIM), injection-compression molding, pultrusion, infusion, vacuum bag molding or pressure bag molding, with no by-product eliminated in the polymerization. The invention also aims to provide a heat-stable composite material PAEK type obtained from said precursor composition for forming the matrix of the composite material.

The invention further aims to provide a method of manufacturing a thermostable composite material PAEK type from such a composition having a relatively low viscosity and less than or equal to 100 Pa.s and allowing either a good coating and good distribution of the fibers when such fibers are incorporated directly into the composition in the molten state, that is a good impregnation of a fibrous substrate, so as to obtain a PAEK type composite material having good thermomechanical properties . Finally, the object of the invention is to provide a functional and / or mechanical part or a structural element made of composite material of the PAEK type. [Brief description of the invention!

The invention relates to a composition for composite material or composition of poly (aryl ether ketone) type composite material (PAEK), said composition being characterized in that it comprises at least one reactive prepolymer of formula X- (EKKE) -X and / or X- (PAEK) -X with a degree of polymerization n such that 1 <n <15 and preferably 2 <n <10, wherein X represents two identical terminal reactive functions each by a benzoyl group or a terminal phenoxy group, said X functions being able to react with one another or with a chain extender by addition reactions. Such a composition based on monomers (when n = 1) or telechelic oligomers of low molecular weight is very advantageous because on the one hand, it has a low viscosity in the molten state, typically less than or equal to 100 Pa.s, and preferably less than or equal to 50 Pa.s, which makes it possible to coat or impregnate fibrous reinforcements and secondly, the telechelic monomers or oligomers are capable of reacting with one another or with an extender of chain, with kinetics compatible with industrial processes, to form a thermostable polymer matrix.

According to other optional characteristics of the composition:

it furthermore comprises at least one chain extender of formula Y-A-Y, in which A represents a bi-radical of non-polymeric structure, and Y represents two identical terminal reactive functions that are capable of reacting by polyaddition with at least one X-function of the reactive prepolymer X- (EKKE) -X and / or X- (PAEK) -X;

the reactive functional groups X of the reactive prepolymer X- (EKKE) -X and / or X- (PAEK) -X are chosen from one of the following functions: -NH ₂ , -

NH (R 1) wherein R 1 represents an aliphatic radical, -CN, -CH ₂ CN, -COOH, -CH ₂ COOH, cyclic ether functions, polycarbonates, cyclic anhydrides and imino-ethers;

the reactive functions Y of the chain extender of formula Y-AY are chosen from one of the following functions: imino-ether functions, carboxylic acid functions, cyclic ether functions, polycarbonates functions, cyclic anhydride functions, nitrile functions and primary and secondary amino functions;

the molar ratio of the reactive functions X / Y is between 0.8 and 1, 2 and preferably equal to 1; the reactive monomer X- (EKKE) -X can be obtained by acylation of

Friedel-Crafts between a mono-functionalized monomer X, such as mono-substituted diphenyl ether (DPE-X) and terephthalic or isophthalic acid chloride;

the reactive oligomer X- (PAEK) -X is preferably a di-functionalized oligomer of X- (PEKK) -X or X- (PEEK) -X, with a degree of polymerization n such that n <15 and preferably n <10;

the composition contains reinforcing fibers;

the composition does not contain reinforcing fibers and is intended to impregnate a fibrous substrate. The invention also relates to a polymer composite material comprising a PAEK type polymer matrix and a fiber reinforcement, said composite material being characterized in that the polymer matrix is obtained after polymerization of the composition described above.

According to another characteristic of the composite material, the polymer matrix comprises EKK type patterns and / or EEK type patterns.

The invention also relates to a method for manufacturing a composite material of the PAEK type, starting from the composition as described above, said process being characterized in that it comprises a polymerization step by heating the composition, with extension of the chains of the reactive prepolymer by melt mass polyaddition reaction.

According to other optional features of the method:

the polymerization is carried out in a closed mold;

- When the composition does not contain reinforcing fibers, a step prior to the polymerization step comprises impregnating a fibrous substrate with said composition in the molten state; the process comprises, simultaneously with the polymerization step, a step of implementation and / or molding;

the impregnation step of the fibrous substrate is carried out in a closed mold; the closed mold may comprise a system for evacuation and / or expansion;

the impregnation and polymerization steps are carried out in the same closed mold;

the polymerization step is carried out at a temperature of between 200 and 400 ° C .;

the process is chosen from one of the following processes: transfer molding (RTM), infusion, injection-compression molding, reaction injection molding (RIM), injection molding-reinforced reaction (R), RIM), structural reaction injection molding (S-RIM), pultrusion, vacuum bag molding, pressure bag molding.

Finally, the invention relates to a mechanical or functional part or structural member PAEK composite material as described above, or obtained according to the manufacturing method as described above. This piece can be an auto part, a boat part, a train piece, a sporting article, an airplane or helicopter part, a spaceship or rocket piece, a photovoltaic module part, a piece of wind turbine, a piece of furniture, a building or building room, a piece of telephone or cell phone, a computer or television room, a printer and photocopier room, or a biocompatible room for medical implant.

Other advantages and features of the invention will become apparent on reading the following description given by way of illustrative and non-limiting example. [Description of the invention!

The term "monomer" as used refers to a molecule that can undergo polymerization.

The term "oligomer" as used refers to a molecule characterized by a chain consisting of a small number of monomer units, generally between 2 and a few tens.

In the present description, the term "prepolymer" is understood to mean a monomer or an oligomer having reactive functions which enable it to participate in a subsequent polymerization and thus to incorporate several monomer units in at least one chain of the final macromolecule.

The term "polymerization" as used refers to the process of converting a monomer or oligomer into a polymer.

The term "thermoplastic polymer" as used refers to a polymer that turns into a liquid or becomes more liquid or less viscous when heated and that can take on new forms through the application of heat and pressure.

The term "thermosetting polymer" as used refers to a pre-polymer in a flexible, solid or viscous state which is irreversibly converted into an insoluble and non-heat-formable polymer network. By "composite material" is meant a macroscopic combination of two or more materials immiscible with each other, that is to say a material forming the polymer matrix which ensures the cohesion of the structure of the final composite material and a reinforcing material, generally fibrous.

The term "fibrous reinforcement" covers both short fibers intended to be incorporated into the matrix in the molten state and coated with the matrix, and fibrous substrates intended to be impregnated with the matrix in the molten state. .

The term "fibrous substrate" as used refers to fabrics, felts or nonwovens which may be in the form of strips, webs, braids, locks or pieces. The fibrous substrate is intended to be impregnated with the polymer matrix in the molten state. The polyarylene ether ketones (PAEKs) used in the invention comprise the following units of formulas:

(- Ar - X -) and (- An - Y -)

 in which: - Ar and An each denote a divalent aromatic radical;

Ar and An may be chosen, preferably, from 1,3-phenylene, 1,4-phenylene, 4,4'-biphenylene, 1,4-naphthylene, 1,5-naphthylene and 2, 6- naphthylene;

X denotes an electron-withdrawing group; it can be chosen, preferably, from the carbonyl group and the sulphonyl group,

Y denotes a group chosen from an oxygen atom, a sulfur atom and an alkylene group, such as -CH ₂ - and isopropylidene.

In these X and Y units, at least 50%, preferably at least 70% and more particularly, at least 80% of the X groups are a carbonyl group, and at least 50%, preferably at least 70% and more particularly at least 80% of the Y groups represent an oxygen atom.

According to a preferred embodiment, 100% of the X groups denote a carbonyl group and 100% of the Y groups represent an oxygen atom.

More preferably, the polyarylene ether ketone (PAEK) may be chosen from:

a poly-ether-ketone-ketone, also called PEKK, comprising units of formula I A, of formula I B and their mixture:

a poly-ether-ether-ketone, also called PEEK, comprising units of formula II:

 Formula II The concatenations can be totally para (Formula II). In the same way, it is possible to introduce, partially or totally, meta sequences in these structures at the level of the ethers and the ketones according to the two examples of the formulas III and IV below:

Formula III

Or :

Formule IV

Form IV

Or sequences in ortho according to the formula V:

Formula V

- un poly-éther-cétone, également nommé PEK, comprenant des motifs de formule VI :

a poly-ether-ketone, also called PEK, comprising units of formula VI:

 Form VI

In the same way, the sequence can be totally para but one can also introduce meta links partially or totally (formulas VII and VIII):

Form VII

 Form VIII

a poly-ether-ether-ketone-ketone, also called PEEKK, comprising units of formulas IX:

 Form IX

In the same way we can introduce meta sequences in these structures at the level of ethers and ketones. a poly-ether-ether-ether-ketone, also called PEEEK, comprising units of formulas X:

Formula X

In the same way we can introduce meta sequences in these structures at the level of ethers and ketones but also biphenolic chains according to formula XI:

 Form XI

Other arrangements of the carbonyl group and the oxygen atom are also possible.

To enable the implementation of a PAEK-type polymer in a process for manufacturing a composite material whose matrix is of PAEK type, it is advantageous to use a reactive precursor composition of relatively low viscosity intended to form the matrix of the composite material. This matrix will be reinforced by fibrous reinforcements. For this, the precursor composition must allow, in the molten state, a good incorporation and good distribution of fibers in the composition itself, or a good impregnation of a fibrous substrate. It must also be capable, after polymerization reaction, without by-product formation, to ensure excellent cohesion of the composite material and optimum transmission of forces to the reinforcing fibers.

This composition advantageously comprises a reactive precursor which has a low melt viscosity, preferably less than or equal to 100. Pa.s, more preferably less than or equal to 50 Pa.s and even more preferably, between 0.1 and 10 Pa.s. The viscosity of the composition can easily be measured with a rheometer. The melt viscosity is measured, with an oscillatory rheometer as a function of time, at 350 ° C. (this temperature is adjusted according to the product to be analyzed), under nitrogen, with a frequency of oscillation, also called solicitation, of 1 Hz, and with a strain amplitude of 5%.

The melting temperature of the reactive precursor is preferably less than 350 ° C in order to be implemented in conventional methods of manufacturing composite materials. The composition also has good thermal stability in the molten state, during its implementation. The reactive ends of the reactive precursor are capable of reacting with each other or with a chain extender without condensation.

Advantageously, the composition for a composite material, or the composition of PAEK-type composite material, according to the invention comprises at least one reactive monomer of formula X- (EKKE) -X and / or a reactive oligomer of formula X- (PAEK) -X, with a degree of polymerization n such that 1 <n <15, and preferably 2 <n <10, as a reactive precursor. X represents two identical terminal reactive functions each carried by a benzoyl group or a terminal phenoxy group.

The EKKE, with sequences 100% para for example, is a low molecular weight monomer synthesized by Friedel-Crafts acylation. It has the advantage of having a melting temperature of 216 ° C and being stable up to about 300 ° C. On the other hand, it does not have any reactive function. This monomer is therefore advantageously functionalized to obtain a reactive precursor of formula X- (EKKE) -X.

The di-functional monomer of formula X-EKKE-X is very fluid and has a viscosity, in the molten state, generally less than or equal to 1 Pa.s. Such viscosity is completely compatible with conventional methods of manufacturing composite materials such as RTM, RIM, R-RIM, S-RIM, injection-compression molding, pultrusion infusion, etc. X represents two identical terminal reactive functions, which are capable of reacting with one another or with a chain extender, by mass polyaddition reaction.

When the degree of polymerization n is greater than 1, that is to say when the prepolymer is a di-functional oligomer of type X- (PAEK) -X (at least 75% of all chain ends being functions of nature X), the viscosity increases. In order to be able to use the composition in a conventional process for manufacturing a composite material, its melt viscosity must be less than 100 Pa.s and preferably less than or equal to 50 Pa.s. To obtain such a viscosity, the degree n of polymerization is preferably less than or equal to 15 and, even more preferably, it is less than or equal to 10. In this case, the molar mass of the oligomer is preferably lower than at 10,000 g / mol.

Such a reactive precursor composition may or may not contain reinforcing fibers. If it contains fibers, these are preferably short, and incorporated in the melt composition by kneading or extrusion, in order to be properly distributed within the composition. The viscosity of the reactive precursor composition being less than or equal to 100 Pa.s, and preferably less than or equal to 50 Pa.s, it allows a homogeneous distribution of the fibers within the composition and a good coating of the fibers. In this case, a subsequent polymerization step, by mass polyaddition reaction, at a temperature of between 200 and 400 ° C. makes it possible to obtain a composite material. The polymerization temperature is advantageously chosen according to the stability of the reagents involved and / or the polymerization kinetics and preferably above the melting point of the mixture. Such a polymerization can be carried out in closed mold for example, so as to allow the shaping of a mechanical part or a structural element simultaneously with the polymerization step. Such a mold may nevertheless comprise a vacuum system and / or an expansion system.

In the case where the precursor composition does not contain fibers, then it can be used to impregnate a fibrous substrate. A subsequent polymerization step of the preimpregnated fibrous substrate, by bulk polyaddition reaction, at a temperature of between 200 and 400 ° C. and chosen as a function of the stability of the reagents involved and / or the kinetics of polymerization and of Preferably, above the melting point of the mixture, it is then possible to obtain a composite material. In this case, the impregnation and / or polymerization step may be carried out in a closed mold, for example, so as to allow the shaping of a mechanical part or a structural element simultaneously with the step of polymerization. Preferably, the two successive steps are carried out in the same closed mold.

Regarding the X-reactive functional groups of the X- (EKKE) -X and / or X- (PAEK) -X prepolymer of the composition of the reactive precursor composition, they are preferably chosen from one of the following functions: -NH ₂ , -NH (R 1) wherein R 1 represents an aliphatic radical, -CN, -CH ₂ CN, -COOH, -CH ₂ COOH, the cyclic ether functions, the polycarbonates functional groups, the cyclic anhydride functions and the imino-functional functions. ethers.

The synthesis of the bi-functionalized EKKE monomer is preferably carried out by Friedel-Crafts acylation between a mono functionalized monomer X, such as mono substituted diphenyl ether (DPE-X) for example, and terephthalic acid chloride, noted TPC thereafter, or isophthalic acid chloride, noted CPI thereafter. However, the amine functions do not make it possible to envisage a direct synthesis of ₂ HN-EKKE-NH ₂ by this route because of their activating electro-donating effect. In order to be able to synthesize such a pre-polymer, an intermediate product of EKKE dinitro O ₂ N-EKKE-NO ₂ , whose function NO ₂ , by its electroattractant deactivating effect, allows the synthesis by acylation of Friedel-Crafts is thus synthesized. . EKKE dinitro is then chemically reduced to obtain the reactive prepolymer of EKKE di-NH ₂ .

Among these reactive terminal functions X of the pre-polymer, the nitrile functions can react with each other by polyaddition to give a trimer comprising EKKE motifs and a triazine bridge for example. Similarly, the acid functional groups can also react with one another by polyaddition to form a PAEK-type polymer comprising carboxylic anhydride bridges and EKK-type units. Moreover, the amine and acid functions are capable of reacting with at least one chain extender. In this case, the precursor composition comprises the reactive monomer of formula X- (EKKE) -X and / or the reactive oligomer X- (PAEK) -X and at least one chain extender of formula Y-AY, in which A represents a bi-radical of non-polymeric structure, and Y represents two identical terminal reactive functional groups, capable of reacting by polyaddition with at least one X function of the reactive monomer. In this case, the Y functions of the chain extender react with the X functions of the reactive monomer of formula X- (EKKE) -X and / or the reactive oligomer X- (PAEK) -X, in forming a bridge, denoted "ZAZ", according to the following reaction (a):

X- (EKKE) -X + Y-YY ► - (EKKE) -ZAZ- (EKKE) - (a) [0058] This reaction corresponds to chain extension by polyaddition, that is to say by repeated addition several times . These "ZAZ" bridges have an influence on the final properties of the composite material obtained after polymerization.

The reactive Y functions of such a chain extender are for example chosen from one of the following functions: imino-ether functions, carboxylic acid functions, cyclic ether functions, polycarbonate functions, cyclic anhydride functions , nitrile functions and primary and secondary amino functions.

The X and Y functions are chosen from the same functions, but the X / Y couple will advantageously be chosen so that the polyaddition reaction can take place.

When the X functions react with the Y functions of the chain extender to form, by addition reaction, "ZAZ" bridges, the iminoether functions preferably react with the acid functions. The polycarbonates, and in particular the ester polycarbonates, as well as the cyclic anhydrides or the cyclic di-ether, preferably react with the primary amine functions - NH ₂ or secondary amines - NH (R 1) by addition reaction.

Among the chain extenders carrying imino-ether functional groups, imidazolines, oxazines or oxazolines may for example be mentioned. These functions react with the acid functions (X = -COOH or -CH ₂ COOH) of the polyaddition-reactive prepolymer. Among the oxazolines, there may be mentioned, for example, the 1, 3 and 1,4-phenylene bis (2-oxazoline), denoted respectively 1,3-PBOX and 1,4-PBOX, and pyridine bis (2-oxazoline), denoted PyBOX. They are thermally stable. The 1,3-PBOX has a lower melting temperature Tf, which facilitates the processing methods using it. It also makes it possible, by the presence of the substitution in meta, to modulate the crystallinity level of the synthesized polymers as well as their thermal properties with respect to 1,4-PBOX. The choice of the chain extender between 1, 3-PBOX and 1, 4-PBOX will therefore be based on the properties desired for the final polymer.

Among the chain extenders carrying polycarbonate functional groups, such as, for example, ester polycarbonates, or cyclic anhydride functional carriers or cyclic di-ethers, which react with terminal amine functional groups of the reactive prepolymer, by polyaddition, mention may be made, for example, of the bisphenol A carbonate oligomers, the pyromellitic dianhydride, referred to as PMDA, and the benzophenone -3,3 ', 4,4'-tetracarboxylic dianhydride, denoted BTDA, as well as the diglycidyl ether of bisphenol Noted DGEBA.

For the polymer constituting the matrix of the final composite material to have high molecular weights, and to obtain a composite material having good thermomechanical properties, it is necessary to adjust the molar ratio X / Y of the reactive functions. pre-polymer and chain extender. This ratio can vary between 0.8 and 1, 2 knowing that the closer this ratio is to 1, the higher the mass Mn is in the majority of cases. Preferably the ratio of the X / Y reactive functions, respectively of the prepolymer / chain extender, is equal to 1. The invention also relates to a method of manufacturing a composite material, comprising a PAEK-type matrix and a fibrous reinforcement, the matrix being obtained after polymerization of the reactive precursor composition.

The prepolymer X- (PAEK) -X advantageously has a melt viscosity such that, alone or in admixture with a chain extender in the precursor composition, it remains less than 100 Pa.s and preferably less than 50 Pa.s and even more preferably between 0.1 and 10 Pa.s. According to a first embodiment, the precursor composition contains fibrous reinforcements. In this case, short fibers are introduced into the composition in the molten state and kneaded in order to ensure a good distribution in the composition. Depending on the constitutive functional prepolymer constituting the composition, that is to say according to the terminal X functions of the reactive prepolymer, the composition may or may not contain a chain extender. In the case for example where the pre-polymer comprises nitrile functions, the composition does not need to include a chain extender since the nitrile functions react with each other at the time of the polymerization. When the X functions are acid functions, the composition may or may not comprise a chain extender. This will depend on the "ZAZ" bridges that one wishes to create according to the desired properties for the final composite material.

A polymerization step by heating the reactive precursor composition is then carried out at a temperature of between 200 and 400 ° C., the temperature being advantageously chosen as a function of the stability of the reagents involved and the kinetics of polymerization and preferably above the melting point of the mixture. This polymerization stage, with chain extension by melt mass polyaddition reaction, then makes it possible to manufacture the composite material. This step may for example be carried out in a closed mold, so as to allow shaping of the material, simultaneously with the polymerization step and thus to obtain a mechanical part or a structural element made of composite material.

According to a second embodiment, when the composition does not contain reinforcing fibers, a step prior to the polymerization step consists in impregnating a fibrous substrate. In this case, the viscosity of the composition in the molten state, that is to say the viscosity of the pre-polymer alone, or in admixture with a chain extender, under the conditions of impregnation of the fibrous substrate and in particular at the impregnation temperature, is less than 100 Pa.s and preferably less than 50 Pa.s and, even more preferably, between 0.1 and 10 Pa.s. The impregnation temperature is generally greater than the melting temperature and, in the absence of a melting temperature, greater than the glass transition temperature of said prepolymer and the temperature of the melting said chain extender. In the case where the precursor composition is used for impregnating a fibrous substrate, its melt viscosity as well as its kinetics of polymerization will be adapted to the fibrous substrate in order to obtain a correct impregnation of the fibers. Preferably, the polymerization step is carried out at a temperature between 200 and 400 ° C and selected according to the stability of the reagents involved and preferably above the melting point of the mixture. Simultaneously with this polymerization step, a forming step is advantageously carried out by molding in order to obtain a mechanical part or a structural element made of composite material whose matrix is of PAEK type.

In this embodiment, the impregnation step and / or the polymerization step may (may) be carried out in a closed mold. Preferably, the two steps, successive or simultaneous, are performed in the same closed mold. The choice of the constituents of the precursor composition, that is to say the choice of the chain length of the pre-polymer and its terminal reactive functions and the choice of the chain extender, will depend on the composite material. desired and the desired composite material part. This choice will be conditioned in particular by the desired level of reinforcement, that is to say the rate of fibers and their porosities, the volume and the thickness of the final part and the thermomechanical properties sought for the final composite material.

The polymer matrix of the final composite material, which results from the mass polyaddition polymerization of the prepolymer with itself or with a chain extender, has the same main (unitary) repeating units as said prepolymer and bridges or elongation units resulting from the addition reactions between the pre-polymer chains. Thus, when the reactive prepolymer is an X- (PAEK) -X oligomer, it is preferably an X- (PEKK) -X, and the main repeating units of the resulting matrix are EKK motifs, or an X- (PEEK) -X, and the main repeating units of the resulting matrix are EEK patterns. When the constituent polymer of the matrix of the composite material obtained is a thermoplastic polymer, it may be semi-crystalline or amorphous. The polymer obtained may also be a thermosetting polymer.

As regards the fiber reinforcement, it may consist of fibers directly incorporated into the precursor composition in the molten state, or may be in the form of a fibrous substrate intended to be impregnated by the precursor composition in the molten state.

The fibers of constitution of the fibrous reinforcement are in particular fibers of mineral, organic or vegetable origin. Among the fibers of mineral origin, mention may be made of carbon fibers, glass fibers, basalt fibers, silica fibers, or silicon carbide fibers, for example. Among the fibers of organic origin, mention may be made of the polymer fibers chosen from thermosetting polymer, thermoplastic polymer fibers or their mixtures. Preferably, these fibers have a melting temperature Tf greater than the Tf of the reactive precursor composition intended to form the matrix of the composite material when the latter is semi-crystalline. Thus, there is no risk of fusion for the organic fibers constituting the fibrous reinforcement.

These fibers of constitution can be used alone or in mixtures. Thus, organic fibers can be mixed with the mineral fibers. The fibers are optionally single-strand, multi-strand or a mixture of both, and may have several grammages. They can also have several geometries. Thus, they can be in the form of short fibers. Such short fibers can then be directly incorporated into the melt reactive precursor composition, and kneaded to be homogeneously distributed in the composition and to be properly coated with the composition.

According to another embodiment, these fibers may comprise fibrous substrates intended to be impregnated with the reactive precursor composition before polymerization so as to form a pre-impregnated substrate. Such substrates are then felts or nonwovens which may be in the form of strips, webs, braids, locks or pieces, or in the form of continuous fibers, which make up 2D fabrics, fibers or fiber tows. unidirectional (UD) or nonwoven. The fibers constituting the fibrous substrate may also be in the form of a mixture of these reinforcing fibers of different geometries. The fibrous substrate can have different shapes and dimensions, one-dimensional, two-dimensional or three-dimensional. A fibrous substrate comprises an assembly of one or more fibers. When the fibers are continuous, their assembly forms tissues.

Preferably the fibrous substrate is constituted by continuous fibers of carbon, glass or silicon carbide or their mixture, in particular carbon fibers. It is used in the form of a lock or several locks. According to a further aspect, the invention relates to a polymer composite material comprising a PAEK-type polymer matrix and a fibrous reinforcement, said fibrous reinforcement being either in the form of short fibers or in the form of a fibrous substrate. The polymer matrix of PAEK type is obtained after polymerization of the reactive precursor composition comprising at least the reactive prepolymer and, optionally, the chain extender. When the reactive precursor composition is in the molten state, prior to its polymerization, either it contains short reinforcing fibers or it impregnates a fibrous substrate. In one case as in the other, the short fibers or the fibrous substrate are intended to form the fibrous reinforcement capable of ensuring the mechanical strength of the final composite material undergoing mechanical stresses. The polymer matrix of the composite material obtained after polymerization of the reactive precursor composition comprises EKK units, or EEK units, and other units resulting from the coupling between the reactive functions of the pre-polymer itself or with the reactive functions of the polymer. chain extender. Another aspect of the present invention relates to a mechanical part or a structural element of PAEK type composite material obtained according to the method of manufacturing a composite material which has just been described.

At the end of the polymerization, there is then obtained a mechanical part or a structural element of composite material whose polymer matrix is reinforced at impact and has very good thermomechanical properties.

With regard to the method for manufacturing composite parts, various processes conventionally used to manufacture materials composites, can be used to prepare mechanical parts. The resin transfer molding (RTM) process, reaction injection molding (RIM), reinforced reaction injection molding (R-RIM), injection molding and reaction molding, (S-RIM), can be mentioned. injection-compression molding, pultrusion, infusion, vacuum bag molding or pressure bag molding.

The preferred manufacturing methods for the manufacture of composite parts are processes in which the reactive precursor composition is polymerized in a mold, more preferably in a closed mold, so that the final part is shaped simultaneously with polymerization.

When the composition does not contain reinforcing fibers, it is preferably transferred to the fibrous substrate by impregnating the fibrous substrate in a mold, and then polymerized. Advantageously, the impregnation step of the fibrous material is carried out in a closed mold. Preferably, the polymerization step of the reactive precursor composition impregnating said fibrous substrate takes place after the impregnation step in the same mold. More preferably, the impregnation step and the polymerization step are carried out in the same closed mold. Preferably, the process for manufacturing composite parts is chosen from resin transfer molding or infusion.

As regards the use of the composite parts thus manufactured, there may be mentioned automotive applications, nautical applications, railway applications, sports, aeronautical and aerospace applications, photovoltaic applications, computer applications, applications. for telecommunications, wind energy applications and applications for medical implants.

The composite part is in particular an automobile part, a piece of boat, a piece of train, a sporting article, a piece of plane or helicopter, a piece of spaceship or rocket, a piece photovoltaic module, a piece of wind turbine, a piece of furniture, a piece of construction or building, a piece of telephone or mobile phone, a piece of computer or television, a printer and copier part, or a biocompatible piece for medical implant.

Examples

The examples described below do not relate to the manufacture of composite materials. They concern the synthesis of a reactive prepolymer, the manufacture of a reactive precursor composition based on the previously synthesized reactive prepolymer and finally, a step of polymerizing the precursor composition to form a polymer intended to form the matrix of a composite material. It is understood that to obtain a composite material, it is appropriate to either incorporate fibers directly into the reactive precursor composition in the molten state, by mixing, or impregnate a fibrous substrate with the precursor composition reactive in the molten state, prior to the polymerization step.

The various samples synthesized in the various examples below were analyzed by Fourier Transform Infrared (FTIR) and nuclear magnetic resonance (NMR) proton and carbon 13. Their thermal properties were evaluated by thermogravimetric analysis. (ATG) and Differential Scanning Calorimetry (DSC) measurements.

The nuclear magnetic resonance (NMR) spectra of the 1 H proton (300 MHz), the 13 C carbon (75 MHz) and the HSQC (HC) couplings (2D) were recorded using a Brucker spectrometer. 300 MHz. The chemical shifts (δ) are indicated in parts per million (ppm) relative to the deuterated solvents and the tetramethylsilane singlet (TMS) used as internal reference (δ = 0) in the samples. The multiplicities are denoted singlet (s), doublet (d), triplet (t), quadruplet (q) and multiplet (m). Several deuterated solvents (CDCl ₃ , CD ₂ Cl 2, DMSO-d 6, nitrobenzene-d 5) were used according to the solubility of the products. Trifluoroacetic anhydride (ATFA) has also been used to increase the solubility of certain products. In some cases, the samples have been preheated to improve their solubility. The Fourier transform infrared absorption spectra (FTIR) were recorded in the 4000-600 cm ^{-1 region} with a Perkin Elmer spectrometer. Spectrum 2000 FTIR equipped with ATR diamond (acronym for "Attenuated Total Reflection") mono-reflection (type MKII, Specac). The absorptions reported are expressed in wavenumber (cm ^-1 ) and presented in transmittance mode.The products are placed on a platinum with a square diamond cell 2 mm side.A screw adjustable in height can hold them against the measurement cell A blank measurement of the air is performed before each analysis, and a dozen scans are cumulated for each FTIR spectrum.

To perform the differential scanning calorimetry (DSC) measurements, the apparatus used is a TA Instruments DSC Q2000 instrument. The principle of measuring the heat flow DSC is based on the difference measurement of the heat fluxes. exchanged between the sample and the reference. When the furnace experiences a linear upward or downward temperature ramp, the sample TE and reference TR temperatures are measured using thermocouples attached below the cup support trays. The oven temperature T0 is measured by means of a thermocouple placed between the two cups. The heat flows QR and QE exchanged between the furnace and respectively the reference and the sample are thus calculated. The output signal is obtained by the difference of the QR and QE heat flux between the sample and the reference. The cooling of the block is ensured by a system allowing to reach -90 ° C. Temperature and energy calibration was performed with indium as standard (Tf = 156.6 ° C and AHf = 28.45 J / g). Unless specified, all analyzes were carried out under nitrogen (50 mL.min ^-1 ) with test portions ranging from 4 to 15 mg with a ramp of 10 ° C.min ^-1 . [0096] Thermogravimetric analyzes ( ATG) were made with a TA Instrument Q500 This device is composed of two main elements: a very sensitive microbalance coupled to a temperature controlled oven The microbalance is capable of detecting a variation of 0.1 mg for a maximum capacity The sample is placed in a platinum cup and the beam maintains the plate in equilibrium via a current proportional to the mass supported.The temperature is regulated between 30 ° C and 1000 ° C with temperature rises. up to 200 "C.min ^{" 1.} A thermocouple close to the sample monitors the temperature and regulates the heating power. Calibration was performed with Alumel and Nickel with Curie points of 163 ° C and 358 ° C, respectively. All the analyzes were carried out between 30 and 700 ° C. with a temperature rise rate set at 10 ° C. min ^-1 , under nitrogen or in air (20 ml.min ^-1 ), with test sample variations. from 5 to 15 mg.

Example 1 Synthesis of a Reactive Precursor Composition Based on EKKE para-nitrile

The synthesis of the para-substituted NC-EKKE-CN monomer takes place between terephthalic acid chloride (TPC) and 4-phenoxybenzonitrile (DPE-CN) in stoichiometric ratio 1: 2, in the presence of AICb for 45 hours. minutes. The electrophilic aromatic substitution reaction is shown schematically in Figure 1 below.

 Diagram 1

In a 1 L reactor, equipped with a condenser, an addition funnel, a mechanical stirrer and a nitrogen stream, aluminum chloride (AlCl.sub.3) (20.degree. 1 g, 0.375 mol), 4-phenoxybenzonitrile (DPE-CN) (24.4 g, 0.125 mol) and 180 mL of o-DCB. After heating the medium to 60 ° C, a solution of terephthalic acid chloride (TPC) (12.75 g, 0.063 mol) in 180 mL of o-DCB is added dropwise. Once the addition is complete, the solution is heated for 45 minutes at 60 ° C. Once the medium has cooled to room temperature, a solution of 10% hydrochloric acid (850 ml) is added dropwise to the reaction medium immersed in an ice bath in order to precipitate a white suspension for 1 hour. The product is then filtered, washed with water and then with 2L of methanol (MeOH). The product is purified by recrystallization from Ν, Ν-dimethylacetamide (DMAc) (1400 mL) and then washed with acetone. After drying in a vacuum oven at 170 ° C. for 18 h, 29.9 g of substituted NC-EKKE-CN are recovered (92% yield).

Proton NMR and carbon 13 spectra carried out on the product obtained and recorded in deuterated chloroform, demonstrate the synthesis of a telechelic EKKE monomer di-functionalized by nitrile functions, with 20 aromatic protons between 7.95 and 7.16 ppm and aromatic carbons between 195.97 and 107.37 ppm.

1 H NMR (CDCl3 (+ ATFA), d, ppm): 7.18-7.16 (8H, d, H3 and H4); 7.74-7.71 (4H, d, H5); 7.95-7.91 (8H, d, H1 and H2). 13 C NMR (CDCl3 (+ ATFA), d, ppm): 195.97 (C3); 160.1-160.04 (C8 and C7); 140.77 (C2) 134.73 (C10); 133.23 (C5); 132.77 (C4); 130.01 (C1); 19.3 (C9); 19.75 (C6); 18.26 (C12) 107.37 (C1 1).

The IRTF spectrum of the NC-EKKE-CN substituted para allows confirm the synthesis of the expected compound with the disappearance of the band (C = O) of aryl chloride at 1725 cm ^-1 in favor of the appearance of the ketonic (C = O) band at 1648 cm ^-1 . In addition, the characteristic bands of the EKKE skeleton and the -CN-terminal group at 2223 cm ^-1 are also visible.

IRTF (cm-1): 31-10-3084 (aromatic CH), 2223 (C≡N nitrile), 1648 (C = O carbonyl), 1587-1493 (aromatic C = C), 1242 (CO ether) [00101] ATG analyzes were conducted under nitrogen with heating rates of 10 minutes up to 680 ° C. The non-functionalized EKKE monomer is known to sublimate before degrading. The loss temperature of 5% mass of nonfunctional ΙΈΚΚΕ is 300 ° C. The functionalization of ΙΈΚΚΕ by the nitrile functions brings a gain of 109 ° C for the loss temperature of 5% of mass compared to ΙΈΚΚΕ non-functionalized, passing to 409 ° C.

Massive mass 5% (ATG): 409 ° C (under nitrogen)

The DSC analyzes were conducted for three cycles of heating-cooling under nitrogen flow at 10 min. A supercooling phenomenon is observed during the recrystallization of this monomer (and this even with cooling at a rate of 2 ° C.min ^-1 ) Moreover, no T _g is observed. A thermal stability threshold (stability threshold) was determined by looking for the temperature beyond which the heating-cooling cycles are no longer repeatable (with regard to the Tf, Te and their energies). This threshold is more representative of the heat-stable nature of this monomer than the values obtained by ATG because of the possible sublimation of the EKKE structures. For the replaced NC-EKKE-CN this stability threshold is 460 ° C.

Tf (DSC): 300 ° C - Te (DSC): 244 ° C - Thermal Stability Threshold (DSC): 460

° C

Bz Synthesis of a Material by Polvo Addition of Nitrile Functions to One another [00103] The para-substituted NC-EKKE-CN monomer previously synthesized in A) comprises terminal nitrile reactive functions which can react with one another so as to form a trimer. The trimerization reaction is a cyclo-addition involving three nitrile groups which, in combination, form a non-condensing triazine ring. [00104] The trimerization reaction is shown in Scheme 2 below.

Figure 2

The synthesis can be carried out in the presence of a super acid, such as trifluoromethanesulphonic acid, also called triflic acid CF3SO3H. More particularly, the synthesis of the trimer consists of the gradual addition of NC-EKKE-CN previously substituted para-synthesized (0.5 g), on 2.5 ml of triflic acid, at -7 ° C with stirring for 20 min. The medium is then transferred to a mold at room temperature (25 ° C.) for 12 hours. After drying at 60 ° C for 20 minutes, a khaki membrane is obtained by quenching in water with a yield of 99%. A second drying at 140 ° C. under vacuum for 24 hours makes it possible to eliminate traces of water.

The trimerization reaction leads to the formation of a thermosetting polymer of khaki color.

The FTIR analysis of the material obtained shows the disappearance of the v (C≡N) band characteristic of nitrile functions at 2223 cm ^-1 and the appearance of two bands at 1363 and 1518 cm ^-1 characteristic of aromatic triazine rings. . The characteristic signals of an EKKE skeleton are also present, in particular with the appearance of two bands respectively at 1227 cm ^-1 characteristic of the ether functions and at 1655 cm ^-1 characteristic of the ketone functions.

[00108] The TGA analysis shows a different mass loss profile of NC-CN EKKE para-substituted with a mass rd T _pe 5% 452 ° C (against 409 ° C for the NC-EKKE-CN) and a residual rate of 67% at 680 ° C. Tg at 223 ° C is observed in DSC. On the other hand, no other signal appears up to 350 ° C. This makes it possible to define this polymer as amorphous and thermally stable up to 350 ° C. since it has not changed in appearance.

Although the polymer obtained is a thermosetting polymer, and therefore not recyclable, it is of great interest because of its thermomechanical properties. Example 2

A- Synthesis of an intermediate product of EKKE para di-nitro

In a three-necked 500 ml equipped with a condenser, an addition funnel, a magnetic stirrer and a stream of nitrogen, are added aluminum chloride (AlCl ₃ ) (62). 4 g, 0.468 mol), 4-nitrophenyl phenyl ether (DPE-NO ₂ ) (44.8 g, 0.208 mol) and 60 mL of nitrobenzene. After heating the medium to 75 ° C., a solution of terephthalic acid chloride (TPC) (21.12 g, 0.104 mol) in 60 ml of nitrobenzene is added dropwise. Once the addition is complete, the solution is heated for 45 minutes at 75 ° C. Once the medium has cooled to room temperature, it is added dropwise to a 1 L reactor containing 800 ml of 10% hydrochloric acid with mechanical stirring, under a stream of nitrogen, equipped with a refrigerant and immersed in a solution. ice bath to precipitate a white suspension for 1 h. The product is then filtered, washed with water and then with 8 × 200 ml of methanol (MeOH). The product is purified by recrystallization in Ν, Ν-dimethylacetamide (DMAc) (1200 mL) and then washed again with nitrobenzene and finally acetone. After drying in a vacuum oven at 110 ° C. for 18 h, 48.3 g of O ₂ N-EKKE-NO ₂ are recovered (83% yield).

[001 1 1] The synthesis reaction by acylation of Fridel-Crafts from the reagent DPE-NO2 is shown schematically in Figure 3 below.

Figure 3

The proton NMR spectra carried out on the product obtained and recorded in nitrobenzene, demonstrate the synthesis of a telechelic EKKE monomer with 20 aromatic protons between 8.23 and 7.15 ppm.

1 H NMR (hot nitrobenzene-d5, d, ppm): 7.18-7.15 (4H, d, H3); 7.27-7.24 (4H, d, H4); 8.05-8.02 (8H, t, H1 and H2); 8.23-8.20 (4H, d, H5).

[001 13] The IRTF spectrum of the para substituted O2N-EKKE-NO2 makes it possible to confirm the synthesis of the expected compound with the disappearance of the (C = O) aryl chloride band at 1725 cm ^-1 in favor of the appearance of the (C = O) ketone band at 1646 cm ^-1 . In addition, the bands characteristic of the EKKE skeleton and the terminal group -NO 2 at 1599-1346 cm ^-1 are also visible.

IRTF (cm-1): 31-19-3078 (aromatic CH), 1646 (C = O-carbonyl), 1599-1346 (NO ₂ nitro), 1582-1492 (aromatic C = C), 1237 (CO ether). [001 14] ATG analyzes were conducted under nitrogen with heating rates of 10 minutes up to 680 ° C. The non-functionalized EKKE monomer is known to sublimate before degrading. The loss temperature of 5% mass of nonfunctional ΙΈΚΚΕ is 300 ° C. The functionalization of ΙΈΚΚΕ by the nitro functions brings a gain of 103 ° C for the loss temperature of 5% of mass compared to ΙΈΚΚΕ non-functionalized, passing to 403 ° C.

Massive mass 5% (ATG): 403 ° C (under nitrogen)

The DSC analyzes were conducted for three cycles of heating-cooling under nitrogen flow at 10 min. A supercooling phenomenon is observed during the recrystallization of this monomer (even with cooling at a rate of 2 ° C.min ^-1 ). Moreover, no T _g is observed. A thermal stability threshold (stability threshold) was determined by looking for the temperature beyond which the heating-cooling cycles are no longer repeatable (with regard to the Tf, Te and their energies). This threshold is more representative of the heat-stable nature of this monomer than the values obtained by ATG because of the possible sublimation of the EKKE structures. For O2N-EKKE-NO2 para substituted this stability threshold is 300 ° C.

Tf (DSC): 270 ° C - Te (DSC): 218 ° C - Thermal stability threshold (DSC): 300 ° C.

However, such a product does not make it possible to directly synthesize a polymer, but it makes it possible to synthesize another reactive prepolymer.

[001] A prepolymer of EKKE para di-NH ₂ is therefore prepared from the prepolymer of EKKE para di-nitro B- Synthesis of the prepolymer of EKKE para di-NH?

This prepolymer of H ₂ N-EKKE-NH ₂ is prepared by chemical reduction of the O ₂ N-EKKE-NO ₂ previously prepared in step A). The chemical reduction reaction is shown in Figure 4 below:

Figure 4

In a 50 ml bicol, equipped with a refrigerant, a nitrogen flow and a mechanical stirrer, are mixed O2N-EKKE-NO2 (1.0 g, 1.79 mmol). and 5 mL of DMF at 20 ° C. Sodium dithionite (2.3 g, 13.2 mmol) is then added with 2.5 mL of DMF. The reaction medium is then heated at 120 ° C. for 5 hours. After cooling, the flask has a yellowish heterogeneous solution. The addition of 4x25 mL of DMSO dissolves the solid present. After filtration and concentration of the filtrate, a film is obtained. Washing in 270 ml of an EtOH / toluene mixture (50/50 by volume) followed by hot filtration and concentration of the filtrate makes it possible to obtain, after drying in an oven under vacuum at 100 ° C. for 20 hours, 0.677 g of H ₂ N-EKKE-NH ₂ (yield: 75.6%).

¹ H NMR (DMSO-d6, d, ppm): 7.81 -7.78 (8H, m, H1 and H2); 7.00-6.84 (8H, m, H3 and H4); 6.64-6.61 (4H, d, H5); 5.1 (3H, d, H6). IRTF (cm ^-1 ): 1643 (C = O carbonyl), 1597-1493 (aromatic C = C), 1235 (CO ether), 3370 and 3462 (NH ₂ -amines).

C. Synthesis of a PAEK-type polymer from a reactive precursor composition comprising the EKKE para-NH 2 prepolymer The reactive precursor composition comprises, in this example, the previously synthesized prepolymer of EKKE para diamine and the diglycidyl ether of bisphenol A, again noted "DGEBA zero" in the following description, as a chain extender.

In a 25 ml flask are added the previously synthesized H ₂ N-EKKE-NH ₂ (0.173 g, 0.34 mmol), the zero DGEBA (0.17 g, 0.34 mmol) and 10 ml. THF. Once the medium is homogeneous, the THF is evaporated. The powder is then transferred to a 150 mL laboratory autoclave which is sealed and put under a gentle flow of N ₂ for 5 minutes. Once the flow is stopped, the reactor is heated at 230 ° C. for 10 minutes. The reaction is then stopped by manual removal of the oven. Once the reactor cools, the product is recovered. The product obtained is a very hard material, brown in color. It has a mass of 5% on the order of 365 ° C with about 50% residual rate at 680 ° C. DSC analyzes show a Tg close to 155 ° C, reproducible over several cycles up to 300 ° C.

The FTIR analysis of the material obtained shows the disappearance of the characteristic signals of the amines at 3370 and 3462 cm ^-1 .The characteristic signals of an EKKE backbone are present, as shown in the table below.

 The material obtained is a thermosetting, amorphous and thermostable polymer up to a temperature greater than or equal to 300 ° C.

[00125] It is possible to obtain a thermoplastic structure by coupling the DGEBA chain extender with a di-functionalized EKKE monomer or oligomer whose terminal reactive functions are secondary amines of the -NH (Ri) type, where Ri represents an aliphatic radical. Thus, the secondary amino ends can react only once with the chain extender and allow to obtain a thermoplastic matrix, recyclable. By way of example, the prepolymer capable of reacting with DGEBA may be (H ₃ C) HN- (EKK) n -NH (CH ₃ ) or the monomer (H ₃ C) HN- (EKKE) - NH (CH ₃ ).

 Example 3 Synthesis of a reactive prepolymer of EKKE meta di-COOH

In a 1 L three-neck, equipped with a condenser, an addition funnel, a mechanical stirrer and a flow of nitrogen, are added aluminum chloride (AlCl ₃ ) (25). , 1 g, 0.188mol), 4-phenoxybenzoic acid (DPE-COOH) (13.4 g, 0.063 mol) and 90 ml of nitrobenzene. After heating the medium to 75 ° C, a solution of isophthalic acid chloride (IPC) (6.39 g, 0.031 mol) in 90 ml of nitrobenzene is added dropwise. Once the addition is complete, the solution is heated for 5 hours at 75 ° C. After 1 h 30 under these conditions, a gel is formed and is manually divided. After the medium has cooled to room temperature, a solution of 10% hydrochloric acid (300 ml) is added dropwise to the reaction medium immersed in an ice bath in order to precipitate a yellowish suspension for 1 hour. The product is then filtered, washed with water and then with 3 × 300 ml of methanol (MeOH). After washing with acetone (600 ml) and drying in a vacuum oven at 170 ° C. for 18 h, 15.16 g of HOOC-EKKE-COOH meta-substituted are obtained (86.7% yield). The synthesis reaction is shown in Scheme 5 below.

The HOOC-EKKE-COOH pre-polymer substituted meta is a good candidate for in-situ polymerization without condensation. It has a melting temperature Tf of 299 ° C. which corresponds to the limit of the high temperatures tolerated for conventional processes, such as, for example, the RTM process, in particular during the injection and polymerization steps. The proton and carbon 13 NMR spectra carried out on the product obtained and recorded in deuterated chloroform, demonstrate the synthesis of a telechelic EKKE monomer di-functionalized with acidic functions, with 20 aromatic protons between 8.21. and 7.26 ppm and aromatic carbons between 197.43 and 19.56 ppm.

¹ H NMR (CD ² Cl 2 (+ ATFA), δ, ppm): 7.26-7.21 (8H, m, Hs and H ₄ ); 7.78-7.72 (1H, t, Hic); 7.97-7.94 (4H, d, H2); 8.21 -8.09 (7H, m, Hia, Hib and Hs).

¹³ C NMR (CD 2 Cl 2 (+ ATFA), δ, ppm): 197.43 (Cs); 163.14 (C12); 160.42 (Ce); 158.64 (C7); 137.94 (C2); 134.74 (Cib); 134.22 (C10); 133.73 (Cs); 133.14 (C4); 131, 93 (Cia); 129.52 (Cic); 121, 97 (C11); 120.03 (Ce); 19.56 (C9).

The IRTF spectrum of HOOC-EKKE-COOH substituted meta confirms the synthesis of the expected compound with the disappearance of the band (C = O) of aryl chloride at 1725 cm ^-1 in favor of the appearance of the band (C = O) ketone to 1647 cm ^"1. In addition, the characteristic bands of the EKKE backbone and the carboxylic acid terminal group at 1678 and 2400 cm ^-1 are also visible.

IRTF (cm-1): 3200-2400 (aromatic C-H and carboxylic OH), 1678 (C = O carboxyl), 1647 (C = O carbonyl), 1589-1498 (aromatic C = C), 1240 (C-O ether).

The ATG analyzes were conducted under nitrogen with heating rates of 10 minutes up to 680 ° C. The non-functionalized EKKE monomer is known to sublimate before degrading. The loss temperature of 5% mass of nonfunctional ΙΈΚΚΕ is 300 ° C. The functionalization of ΙΈΚΚΕ by the acid functions brings a gain of 59 ° C for the loss temperature of 5% of mass compared to ΙΈΚΚΕ non-functionalized, passing to 359 ° C.

I loss of mass 5% (ATG): 359 ° C (under nitrogen)

The DSC analyzes were conducted for three cycles of heating-cooling under nitrogen flow at 10 min. A supercooling phenomenon is observed during the recrystallization of this monomer (and this even with cooling at a rate of 2 ° C.min ^-1 ) Moreover, no T _g is observed, a threshold of thermal stability ( Stability Tsar) was determined by researching the temperature beyond which the heating-cooling cycles are no longer repeatable (with regard to the Tf, Te and their energies). This threshold is more representative of the heat-stable nature of this monomer than the values obtained by ATG because of the possible sublimation of the EKKE structures. For the meta-substituted HOOC-EKKE-COOH this stability threshold is 375 ° C.

Tf (DSC): 299 ° C - Te (DSC): 253 ° C - Thermal stability threshold (DSC): 375 ° C

Bz Synthesis of a reactive precursor composition comprising the EKKE meta di-COOH prepolymer synthesized in step A) and a chain extender, and polymerization of the composition by mass polyaddition reaction

The reactive precursor composition comprises the precursor of EKKE diacid substituted meta previously synthesized in step A) and 1,4-phenylene bisoxaline, noted 1, 4-PBOX in the following description, as as chain extender. The mixture of HOOC-EKKE-COOH and PBOX is performed manually with stoichiometry of the reactive ends on approximately 10 mg of material. This mixture is then introduced into a DSC capsule. Once the capsule is sealed, it is heated at 240 ° C for 10 minutes. The reaction is then stopped by cooling the apparatus. The product obtained is semicrystalline with a Tg of 148 ° C, a Tf of 255 ° C and a threshold of thermal stability below 270 ° C.

The couplings conducted from the meta-substituted HOOC-EKKE-COOH have been shown to be effective and have allowed the synthesis of low molecular weight polymer whose repeat unit is presented below.

The theoretical repeating unit of the polymers resulting from these couplings is an EKKE with a "ZAZ" aromatic ester-amide bridge composed of a aliphatic chain with two CH ₂ , hereinafter referred to as "ZAZ ester - C2 aromatic amide".

The FTIR analyzes show the disappearance of the characteristic bands v (C = O) carboxylic acid at 1678 cm ^-1 of the HOOC-EKKE-COOH meta substituted and v (C = N) imine at 1640 cm ^-1 of the 1, 4-PBOX in favor of the appearance of the v (C = O) bands of the amide and of the ester respectively at 1536 and 1714 cm- ^1, a broadening of the band at 1648 cm- ¹ corresponds to the superposition of the v (C = O) amide and ketone bands. In addition, the vibration band of the NH bond of the amide is also visible around 3300 cm ^-1 . [00138] The examples which have just been described are based on a di-functionalized EKKE monomer. it is safe to use a di-functionalized oligomer of X- (PAEK) -X type, as long as the degree of polymerization remains less than or equal to 15 and preferably less than or equal to 10, and the viscosity of the precursor composition reactive with the melt state remains less than or equal to 100 Pa.s and preferably less than or equal to 50 Pa.s. By way of example, the oligomer of X- (PAEK) -X type is preferably a di-functionalized oligomer of X- (PEKK) -X or X- (PEEK) -X.

From these reactive precursor compositions which have just been described, it is possible to produce composite materials. For this purpose, either fibers are incorporated directly into the reactive precursor composition, in the molten state, prior to mass polyaddition polymerization, or a fibrous substrate is impregnated with the reactive precursor composition in the molten state, and then polymerized. the preimpregnated fibrous substrate.

[00140]

Claims

1. Composition for composite material or composition of poly (aryl ether ketone) type (PAEK) composite material, said composition being characterized in that it comprises at least one reactive prepolymer, of formula X- (EKKE) -X and / or X- (PAEK) -X with a degree of polymerization n such that 1 <n <15 and preferably 2 <n <10, wherein X represents two identical terminal reactive functions, each carried by a benzoyl group or a terminal phenoxy group, said X functions being able to react with each other or with a chain extender by addition reactions. 2. Composition according to claim 1, characterized in that it further comprises at least one chain extender of formula Y-AY, in which A represents a bi-radical of non-polymeric structure, and Y represents two identical terminal reactive functions. , capable of reacting by polyaddition with at least one X function of the reactive prepolymer X- (EKKE) -X and / or X- (PAEK) -X. 3. Composition according to claims 1 or 2, characterized in that the reactive functions X of the reactive prepolymer X- (EKKE) -X and / or X- (PAEK) -X are chosen from one of the following functions: -NH ₂ , -NH (R 1) wherein R 1 represents an aliphatic radical, -CN, -CH ₂ CN, -COOH, -CH ₂ COOH, the cyclic ether functions, the polycarbonates functional groups, the cyclic anhydride functions and the imino-functional functions. ethers. 4. Composition according to claims 2 and 3, characterized in that the reactive functions Y of the chain extender of formula Y-AY, are chosen from one of the following functions: imino-ether functions, carboxylic acid functions , cyclic ether functions, polycarbonate functions, cyclic anhydride functions, nitrile functions and primary and secondary amine functions. 5. Composition according to claims 2 to 4, characterized in that the molar ratio of the reactive functions X / Y is between 0.8 and 1, 2 and preferably equal to ai. 6. Composition according to at least one of claims 1 to 5, characterized in that the reactive monomer, X- (EKKE) -X, can be obtained by Friedel-Crafts acylation between a mono functionalized monomer X, such as the mono-substituted diphenyl ether (DPE-X) and terephthalic or isophthalic acid chloride. 7. Composition according to at least one of Claims 1 to 5, characterized in that the reactive oligomer X- (PAEK) -X is preferably a di-functionalized oligomer of X- (PEKK) -X or X- (PEEK) -X, with a degree of polymerization n such that n <15 and preferably n <10. 8. Composition according to at least one of claims 1 to 7, characterized in that it contains reinforcing fibers. 9. Composition according to at least one of claims 1 to 7, characterized in that it does not contain reinforcing fibers and is intended to impregnate a fibrous substrate. 10. A polymer composite material comprising a PAEK-type polymer matrix and a fiber reinforcement, said composite material being characterized in that the polymer matrix is obtained after polymerization of the composition according to at least one of claims 1 to 9. Polymer composite material according to claim 10, characterized in that the polymer matrix comprises EKK type patterns and / or EEK type patterns. 12. A method of manufacturing a composite material of the PAEK type, from the composition according to at least one of claims 1 to 9, said method being characterized in that it comprises a polymerization step by heating the composition. with chain extension of the reactive prepolymer by melt mass polyaddition reaction. 13. The method of claim 12, characterized in that the polymerization is carried out in a closed mold. 14. The method of claim 12 or 13, characterized in that when the composition does not contain reinforcing fibers, a step prior to the polymerization step comprises impregnating a fibrous substrate with said composition in the molten state. 15. The method of claims 12 to 14, characterized in that it comprises, simultaneously with the polymerization step, a step of implementation and / or molding. 16. The method of claim 14, characterized in that the impregnating step of the fibrous substrate is carried out in a closed mold. 17. Process according to claims 14 to 16, characterized in that the impregnation and polymerization steps are carried out in the same closed mold. 18. Method according to one of claims 12 to 17, characterized in that the polymerization step is carried out at a temperature between 200 and 400 ° C. 19. Method according to one of claims 12 to 18, characterized in that the method is chosen from one of the following methods: transfer molding (RTM), infusion, injection-compression molding, molding by injection reaction (RIM), injection molding - reinforced reaction (R-RIM), structural injection reaction molding (S-RIM), pultrusion, vacuum bag molding, pressure bag molding. 20. Mechanical or functional part or structural element of PAEK composite material according to one of claims 10 to 1 1, or obtained according to the manufacturing method according to at least one of claims 12 to 19. 21. Part according to claim 20, said part being an automobile part, a boat part, a train piece, a sporting article, an airplane or helicopter part, a piece of spaceship or rocket. , a piece of photovoltaic module, a piece of wind turbine, a piece of furniture, a piece of construction or building, a piece of telephone or mobile phone, a computer or television room, printer and photocopier room, or biocompatible piece for medical implant.