EP1483332A2 - Compositions with poly(ethynylene phenylene ethynylene silylenes) - Google Patents

Abstract

Compositions comprising a mixture of at least one poly(ethynylene phenylene ethynylene silylene) and at least one compound with a plastifying effect on the mixture once the above has hardened.

Description

 PO Y COMPOSITIONS (ETHYNYLENE PHENYLENE ETHYNYLENE SILYLENES)

DESCRIPTION

The present invention relates to compositions comprising polymers of the poly (ethynylene phenylene ethynylene silylene) type.

The invention also relates to the cured products capable of being obtained by heat treatment of said compositions.

The polymer compositions according to the invention can in particular be used in matrices for composites. The technical field of the present invention can be defined as that of thermostable plastics, that is to say polymers which can withstand high temperatures which can reach for example up to 600 ° C. The industrial needs for such thermostable plastics have increased enormously in recent decades, particularly in the electronic and aerospace fields.

Such polymers have been developed to remedy the shortcomings of materials previously used in similar applications.

Indeed, we know that metals such as iron, titanium and steel are thermally very resistant, but they are heavy. Aluminum is light but not very resistant to heat, ie up to around 300 ° C. Ceramics such as SiC, If ₃ N ₄ and silica are lighter than metals and very resistant to heat but they are not moldable. This is the reason why many plastics have been synthesized which are light, moldable and have good mechanical properties; these are mainly carbon-based polymers.

Polyimides have the highest heat resistance of all plastics with a thermal deformation temperature of 460 ° C, however these compounds which are listed as being the most stable known at present are very difficult to use. Other polymers such as polybenzimidazoles, polybenzothiazoles and polybenzooxazoles have a heat resistance still higher than that of polyimides but they are not moldable and they are flammable.

Polymers based on silicon such as silicones or carbosilanes have also been widely studied. The latter, such as poly (silylene ethynylene) compounds, are generally used as ceramic precursors of the silicon carbide SiC type, resist compounds and conductive materials.

It has recently been shown in document [4] that poly [(phenyl silylene) ethynylene-1, 3-phenylene ethynylene] (or MSP) prepared by a synthesis process involving polymerization reactions by dehydrocoupling between phenylsilane and m-diethynylbenzene exhibited remarkably high thermal stability. This is confirmed in document [1] which highlights more general the excellent thermal stability properties of poly (silylene ethynylene phenylene ethynylenes) which have a repeating unit represented by the following formula (A):

The synthesis of polycarbosilanes comprising a silane function and a diethynylbenzene by conventional methods with metallic catalysts leads to polymers of low purity containing significant traces of metallic catalyst greatly affecting their thermal properties.

Other improved synthesis methods are presented in document [2]: these are syntheses catalyzed by palladium but which in fact only apply to a very limited number of specific polymers in which the silicon carries example two phenyl or methyl groups. In particular, it will be noted that the compounds whose repeating unit has been described above by formula (A) cannot be synthesized by this process. However, it turns out that the SiH bonds of such compounds which are particularly difficult to obtain are very advantageous since they are extremely reactive and can give rise to multiple rearrangements and reactions.

Another process for cross dehydrocoupling or polycondensation of silanes with alkynes in the presence of a catalytic system based on copper chloride and an amine is described in document [3]. This process is however also limited to a few polymers and results in compounds whose structure is partially crosslinked and the average molecular weight by mass very high (10 ⁴ to 10 ⁵ ). These structural defects seriously affect both the solubility properties and the thermal properties of these polymers.

Another synthetic process aiming to remedy the drawbacks of the processes described above, and to prepare pure compounds, without traces of metals, and with excellent and well defined properties, notably of thermal stability, has been proposed in the document [ 4], already mentioned above. This process essentially allows the synthesis of the compounds of formula (A) above in which the silicon carries a hydrogen atom. The process according to [4] is a polycondensation by dehydrogenation of a hydrosilane functionalized with a compound of diethynyl type in the presence of a metal oxide such as MgO according to the following reaction scheme (B):

This process leads to weakly crosslinked polymers with, as shown above, excellent thermal stability, but the mass distribution of which is however very wide.

In another more recent publication [1], the same authors prepared a series of polymers comprising the motif -Si (H) -C = C- by method (B) and by another more advantageous method, involving the reaction of condensation of dichlorosilane and diethynyl organomagnesium reagents then reaction of the product obtained with a monochlorosilane followed by hydrolysis according to the following reaction scheme (C):

Unlike process (B), process (C) makes it possible to obtain polymers without structural defects with good yields and a low mass distribution.

The compounds obtained by this process are perfectly pure and have perfectly characterized thermal properties. These are thermosetting polymers.

This document also discloses the preparation of the above-mentioned polymers reinforced with glass, carbon or SiC fibers.

A patent relating to polymers comprising the very general repeating unit (D):

in which R and R 'concern many groups known in organic chemistry, was granted to the authors of documents [1] and [4], it is the document

EP-B1-0 617 073 (corresponding to the American patent

US-A-5,420,238).

These polymers are prepared essentially by the method of scheme (C) and optionally by the process of scheme (B), and they have a weight average molecular weight of 500 to 1,000,000. document also describes cured products based on these polymers and their preparation by a heat treatment. It is indicated that the polymers of this document can be used as thermostable polymer, fire-resistant polymer, conductive polymer, material for electroluminescent elements. In fact, it appears that such polymers are essentially used as organic precursors of ceramics. The excellent thermal stability of the polymers prepared in particular in document EP-B1-0 617 073 makes them capable of constituting the resin forming the organic matrix of thermostable composite materials. Many techniques for making composites exist.

In a very general way, the different processes call for injection techniques,

(in particular RTM), or to prepreg compaction techniques.

Prepregs are semi-finished products of small thickness made of fibers impregnated with resin. The prepregs which are intended for producing high performance composite structures, contain at least 50% fiber by volume.

Also, during processing, the matrix must have a low viscosity to penetrate the reinforcing ply and properly impregnate the fiber in order to avoid its distortion and to preserve its integrity. The reinforcing fibers are impregnated either by a resin solution in an appropriate solvent, or by pure resin in the molten state, this is the so-called "hot elt" technique. The technology for manufacturing prepregs with a thermoplastic matrix is largely governed by the morphology of the polymers.

Injection molding is a process which consists in injecting the liquid resin into the textile reinforcement previously positioned in the impression formed by the mold and the counter-mold. The most important parameter is the viscosity which must be between 100 and 1000 mPa.s at the injection temperature which is generally 50 to 250 ° C.

For these two techniques, viscosity is therefore the critical parameter which conditions the ability of the polymer to be used.

However, amorphous polymers correspond to macromolecules whose skeletal structure is completely disordered. They are characterized by their glass transition temperature (Tg) corresponding to the transition from the glassy state to the rubbery state. Beyond Tg, thermoplastics are however characterized by a high creep resistance.

The polymers prepared in document EP-B1-0 617 073 are compounds which are in powder form. The inventors were able to show, by reproducing the syntheses described in this document, that the polymers prepared would produce glass transition temperatures close to 50 ° C. Before this temperature, the viscosity of the polymer is infinite and beyond this temperature, the viscosity decreases as the temperature is increased.

However, this drop in viscosity is not sufficient for the polymer to be able to be used by methods conventionally used in the world of composites such as RTM and prepreg already described above.

Document FR-A-2 798 662 by BUVAT et Al. Describes polymers with a structure similar to that of the polymers described in patent EP-B1-0 617 073, that is to say which have all their advantageous properties, in particular thermal stability, but whose viscosity is sufficiently low for them to be able to be used, manipulated, "processable" at temperatures, for example of

100 to 120 ° C, which are the temperatures commonly used in injection or impregnation techniques.

These polymers, described in document FR-A-2 798 662, correspond to the following formula (I):

or to the following formula (la) 10

We can refer to the document

FR-A-2 798 662 for the meaning of the various symbols used in these formulas. It is important to note that the polymers according to FR-A-2 798 662 have a structure substantially similar to that of the polymers of document EP-B1-0 617 073, with the fundamental exception, however, of the presence at the end of chain of Y groups from a chain limiting agent. The thermostable polymers of FR-A-2 798 622 have perfectly defined and modular rheological properties, which allows their use as matrices for thermostable composites. All of the properties of these polymers are described in FR-A-2 798 622, to which reference may be made.

Document FR-A-2 798 622 also describes a process for the synthesis of these thermostable polymers. The developed technique allows the viscosity of the polymer to be adjusted at will, depending on the technological constraints of processing the composite. This property is intimately linked to the molecular weight of the polymer. Low viscosities are observed on polymers with low molecular weights. Control masses is obtained by adding to the reaction medium a reactive species which blocks the polymerization reaction without affecting the overall yield of the reaction. This species is an analogue of one of the two reagents, used for the synthesis of the polymer but carrying a single function allowing coupling. When this species is introduced into the polymer chain, growth is stopped. The length of the polymer is then easily controlled by metered additions of chain limiter. A detailed description of the processes for the synthesis of the polymers described above is given in document FR-A-2 798 622, to which reference may be made.

Furthermore, the prepolymers, prepared both in document EP-B1-0 617 073 from ITOH and in document FR-A-2 798 622 from BUVAT, being thermosets, the crosslinking of these materials is thermally activated.

The reactions involved in this phenomenon mainly involve two mechanisms, which are described in an article published by ITOH [5].

The first mechanism is a Diels Aider reaction, involving an acetylenic bond coupled to an aromatic nucleus, on the one hand, and another aromatic bond, on the other. This reaction can be illustrated as follows:

This reaction generates a naphthalene pattern. It is likely to occur regardless of the nature of Ri, R ₂ , R ₃ or R ₄ .

The structures obtained by this mechanism are therefore highly aromatic and contain numerous unsaturated bonds. These characteristics are at the origin of the excellent thermal properties observed on these polymers. The second mechanism, involved in the crosslinking reaction of poly (ethynylene phenylene ethynylene silylene) prepolymers is a hydrosilylation reaction, involving the SiH bond and an acetylene triple bond. This reaction can be illustrated as follows:

This reaction only occurs for compounds in which the silicon carries the SiH bond.

For these latter compounds, the hydrosilylation reaction is activated in the same temperature ranges as the Diels Aider reactions. A polymer network is, among other things, defined by the crosslinking density and by the length of the chain links which separate two crosslinking points. These characteristics largely govern the mechanical properties of polymers. Thus, highly crosslinked networks and weak links are classified in the range of materials with low deformation capacity. Phéholic resins or cyanate phenolic ester resins are in particular part of this class of materials. In the case of poly (ethynylene phenylene ethynylene silylene), crosslinking involves the acetylenic triple bonds, simply separated by an aromatic ring. Consequently, the crosslinking density is very strong and the internode links very short. Cured materials based on poly (ethynylene phenylene ethynylene silylene) are therefore part of the polymer matrices having a low deformation capacity.

The crosslinking density can be controlled during the processing of the polymer by suitable heat treatments. Indeed, the crosslinking of the polymer stops, when the mobility of the macromolecular chains is no longer sufficient. It is assumed that this mobility is sufficient, as soon as the processing temperature is higher than the glass transition temperature of the network. Consequently, the glass transition temperature cannot exceed that of processing and the crosslinking density is therefore controlled by the polymer curing temperature. However, sub-crosslinked materials are unstable materials whose use, at temperatures higher than that of implementation, will cause an evolution of the structure. The mechanical properties of poly (ethynylene phenylene ethynylene silylene) are therefore difficult to modulate by heat treatment. The nature of the chemical groups carried by the silicon is however capable of modulating these properties. Long chains can, in fact, play the role of plasticizer and reduce the rigidity of the associated materials. However, this principle finds limits in terms of thermal stability of the polymer because it is then affected. There is therefore a need for a polymer, or rather for a composition comprising a polymer of the poly (ethynylene phenylene ethynylene silylene) type, which, while having all the advantageous properties of these polymers, and of compositions comprising these copolymers, in particular as regards thermal stability, has, in addition, improved mechanical properties, modular.

There is also a need for compositions comprising polymers of the poly (ethynylene phenylene ethynylene silylene) type which give, by heat treatment, hardened products whose mechanical properties are improved and in which in particular the brittleness, the brittle nature and the hardness are reduced , conversely, flexibility and suppleness are increased. These mechanical properties must be obtained without the other advantageous properties of these cured products, in particular, again, in terms of thermal stability, being affected. In addition, preferably, this polymer and the composition containing it must have a sufficiently low viscosity so that it can be used, manipulated, "processable" at temperatures for example from 100 to 120 ° C. which are the temperatures commonly used. used in injection or impregnation techniques.

The object of the invention is to provide polymer compositions of the poly (ethynylene phenylene ethynylene silylene) type which meet, inter alia, these needs, which do not have the defects, drawbacks, limitations and disadvantages of the polymer compositions of the art as shown in particular by documents EP-B1-0 617 073 and FR-A-2 798 622, and which solve the problems of the prior art.

This object, and others still, are achieved, in accordance with the invention by a composition comprising the mixture of at least one poly (ethynylene phenylene ethynylene silylene) polymer and at least one compound capable of exerting an effect. plasticizer in the mixture, once it has hardened. Compositions comprising the mixture of a specific poly (ethynylene phenylene ethynylene silylene) polymer and of a compound capable, capable of exerting a plasticizing effect in the mixture, a once hardened, are not described in the prior art.

The preparation of a specific mixture, comprising, in addition to a poly (ethynylene phenylene ethynylene silylene) polymer, a compound capable of exerting a plasticizing effect in the mixture once cured leads, precisely and surprisingly to compounds, cured products, whose mechanical properties are greatly improved compared to the hardened products of the prior art, as described, for example, in documents EP-B1-0 617 073 and FR-A-2 798 622, without their thermal properties , which remain excellent, are not affected.

In particular, the cured products prepared by heat treatment, the compositions according to the invention are more flexible, more flexible, less brittle than the cured products prepared by heat treatment of the compositions according to the prior art containing a poly (ethynylene phenylene ethynylene silylene) , and which basically do not include a compound capable of exerting a plasticizing effect.

The compositions according to the invention, thanks in particular to their fundamental characteristic, which is the presence of a compound capable of exerting a "plasticizing" effect, in mixture with the polymer, provide a solution to the problems posed in the prior art and meet the needs listed above.

The preparation of such mixtures was absolutely not obvious to a person skilled in the art since the formulation of polymer compositions, with a view to modifying properties, obeys for the most part random rules and varies extremely considerably from one family of polymers to another; so that it was difficult, if not impossible, to anticipate beforehand that the incorporation of compounds capable of exerting a plasticizing effect in the mixture once it has hardened, would lead to an improvement, mentioned above, of the mechanical properties. , in particular to an increase in the suppleness and flexibility of the hardened material, without, on the other hand, that the other properties, for example thermal, of these materials are not adversely affected.

In more detail, the fundamental compound included in the mixture of the composition of the invention is defined as a compound capable of exerting a plasticizing effect in the mixture, once the latter has hardened.

Generally, the term “compound capable of exerting a plasticizing effect in the mixture”, once it has hardened, is understood to mean any compound which causes an increase (even minimal) in the “plastic” character of the hardened product. that is to say an increase in the deformability of the material constituted by the hardened product under stress - compared to a hardened product not containing said compound.

This means in particular that in the cured products prepared from the compositions according to the invention, the compound exerts an effect of reduction in rigidity, hardness and, conversely, increasing the flexibility of the flexibility of the cured product compared to a cured product including the same polymer, but not containing said compound capable of exerting a plasticizing effect. It is important to note that, according to the invention, the compound "capable of exerting a plasticizing effect" is not necessarily a compound, called plasticizer, as it is commonly defined, in particular in the field of plastics and plastics.

Indeed, this compound can be chosen from many compounds which are not generally defined as being plasticizers, but which, in the context of the invention, are suitable compounds, in that they have a plasticizing effect in the hardened product.

However, the plasticizers known as such can also be used as said compound. In other words, as we have seen above, the hardened products prepared from poly (ethynylene phenylene ethynylene silylene) being extremely hard, rigid, and brittle, the inclusion in such a product of a relatively more flexible compound. that the polymer, although not conventionally listed as "plasticizer", is sufficient to cause an increase in the mobility of the polymer network and therefore to exert a plasticizing effect.

The compound included in the mixture, although not intrinsically a "plasticizer", plays well, then, in the final hardened material the role of a "plasticizer".

The compound capable of exerting a plasticizing effect will therefore generally be chosen from organic and inorganic polymers and resins.

The organic polymers are generally chosen from thermoplastic polymers and thermosetting polymers.

The thermoplastic polymers can be chosen, for example, from fluorinated polymers.

The thermosetting polymers can be chosen, for example, from epoxy resins, polyimides (poly (bismaleimides)), polyisocyanates, formophenolic resins, silicones or polysiloxanes and all other aromatic and / or heterocyclic polymers.

The “plasticizer” compound, such as a polymer, in admixture with poly (ethynylene phenylene ethynylene silylene) and the latter may not be miscible with each other, or else they may exhibit partial miscibility with each other. with each other, or even they can be perfectly miscible with each other.

Preferably, the compound capable of exerting a plasticizing effect such as a polymer is a reactive compound, that is to say capable of reacting with itself or with another compound capable of exerting a plasticizing effect or with poly (ethynylene phenylene ethynylene silylene). Such reactive compounds, such as polymers, generally comprise at least one reactive function, chosen among the acetylenic functions and the hydrogenated silane functions.

Preferably, the reactive compound is chosen from hydrogenated silicone polymers and resins and / or comprising at least one acetylenic function.

The silicone polymers or resins are chosen from polymers and silicone resins having the following formulas:

where Ri and R ₂ , identical or different, represent an alkyl group of 1 to 10 C and in particular a methyl group, and where one or more of the hydrogen atoms carried by the silicon atoms and the carbon atoms can be replaced by a reactive group, such as an acetylene group;

where Ri, R ₂ and R ₃ , identical or different, represent an alkyl group of 1 to 10 C and in particular a methyl group, and where one or more of the hydrogen atoms carried by the silicon atoms and the carbon atoms can be replaced by a reactive group, such as an acetylene group;

where Ri represents an alkyl group of 1 to 10 C and in particular the methyl group, and where one or more of the hydrogen atoms carried by the silicon atoms and the carbon atoms can be replaced by a reactive group, such as an acetylene group;

where Ri, R ₂ and R ₃ , identical or different, represent an alkyl group of 1 to 10 C and in particular the methyl group and where one or more of the hydrogen atoms carried by the silicon atoms and the carbon atoms can be replaced by a reactive group, such as an acetylene group, x and y represent the molar fraction of each of the units concerned and are liable to vary between 0 and 1.

The molar mass of the compound (s) capable of exerting a plasticizing effect is generally between 200 and 10 ^δ g / mol. It is therefore noted that it can be both monomers and oligomers, as well as polymers.

The amount of compound capable of exerting a plasticizing effect introduced during the formulation is between 0.1 and 200% of the mass of the poly (ethynylene phenylene ethynylene silylene silylene) and preferably between 10 and 50%, depending on the properties sought. The polymer of poly (ethynylene phenylene ethynylene silylene) which enters the mixture is not particularly limited, it can be any polymer of this known type, in particular it can be poly (ethynylene phenylene ethynylene silylene) described in documents EP-B1-0 617 073 and FR-A-2 798 662, of which the relevant parts relating to these polymers are included herein.

The polymer can thus, according to a first embodiment of the invention, correspond to the following formula (I):

or to the following formula (la):

in which the phenylene group of the central repeating unit can be in the form o, m or p; R represents a halogen atom (such as F, Cl, Br and I), an alkyl group (linear, or branched) having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms (such as methyl, ethyl, propyl, butyl, cyclohexyl), an alkoxy group having from 1 to 20 carbon atoms (such as methoxy, ethoxy, propoxy), an aryl group having from 6 to 20 carbon atoms (such as a group phenyl), an aryloxy group having 6 to 20 carbon atoms (such as a phenoxy group), an alkenyl group (linear, or branched) having 2 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 carbon atoms (such as vinyl, allyl, cyclohexenyl), an alkynyl group having 2 to 20 carbon atoms (such as ethynyl, propargyl), a amino group, an amino group substituted by one or two substituents having from 2 to 20 carbon atoms (such as dimethylamino, diethylamino, ethylmethylamino, methylphenylamino) or a silanyl group having from 1 to 10 silicon atoms (such as silyl, disilanyl ( -If ₂ H ₅ ), dimethylsilyl, trimethylsilyl and tetramethyldisilanyl), one or more hydrogen atoms linked to the carbon atoms of R may be replaced by halogen atoms

(such as F, Cl, Br and I), alkyl groups, alkoxy groups (such as methoxy, ethoxy and propoxy), aryl groups, aryloxy groups (such as a phenoxy group), amino groups, amino groups substituted with one or two substituents or silanyl groups; n is an integer from 0 to 4 and q is an integer from 1 to 40; R 'and R'', identical or different, represent a hydrogen atom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an alkoxy group having from 1 to 20 atoms carbon, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 carbon atoms , an alkynyl group having 2 to 20 carbon atoms, one or more of the hydrogen atoms bonded to the carbon atoms of R 'and R''may be replaced by halogen atoms, alkyl groups, alkoxy groups, aryl groups, aryloxy groups, amino groups, disubstituted amino groups or silanyl groups, examples of these groups have already been cited above for R; and Y represents a group derived from a chain-limiting agent.

The polymers according to this embodiment of the compositions of the invention, which are the polymers described in document FR-A-2 798 662, have a structure substantially similar to that of the polymers of document EP-B1-0 617 073 to 1 'fundamental exception, however, the presence at the chain end of the Y groups from a chain limiting agent. This structural difference has very little influence on the advantageous properties of these polymers, in particular the thermal stability properties of the polymer, which are hardly affected. On the other hand, the presence at the chain end of this group has precisely the effect that the polymer of formula (I) or (la) has a determined length and therefore a molecular mass, perfectly defined.

Consequently, this polymer (I) or (la) also has perfectly defined and modular rheological properties.

The nature of the group Y depends on the nature of the chain-limiting agent from which it is derived, Y may, in the case of polymers of formula (I), represent a group of formula (III):

wherein R "'has the same meaning as R and may be the same or different from the latter, and n' has the same meaning as n and may be the same or different from the latter.

Or then Y could, in the case of polymers of formula (la), represent a group of formula (IV):

R *

If- R "

(IV)

_R , „

in which R ', R "and R"' which may be identical or different have the meaning already given above.

A particularly preferred polymer of formula (I) corresponds to the following formula:

where q is an integer from 1 to 40.

Other polymers which can be used in the compositions of the invention are polymers of determined molecular mass, capable of being obtained by hydrolysis of the polymers of formula (la) and corresponding to the following formula (Ib):

in which R, R ', R' ', n and q have the meaning already given above.

The molecular mass of the polymers (I), (la) and (Ib) according to this embodiment of the invention is perfectly defined and the length of the polymer and therefore its molecular mass can be easily controlled by metered additions of chain limiter in the mix reaction reflected by variable proportions of group Y in the polymer.

Thus, according to the first embodiment of the composition of the invention, the molar ratio of the end Y groups to the repeating units ethynylene phenylene ethynylene silylene is generally from 0.01 to 1.5. Preferably, this ratio is 0.25 to 1.

Likewise, according to this first embodiment of the composition of the invention, the molar proportion of the Y groups at the end of the chain is generally from 1 to 60 and preferably from 20 to 50% of the polymer of formula (I) or ( the) .

The number-average molecular mass of the polymers (I), (la) and (Ib) according to this first embodiment of the composition of the invention, which is perfectly defined, is generally from 400 to 10,000, preferably from 400 to 5000 and the weight average molecular weight is from 600 to 20,000, preferably from 600 to 10,000.

According to a second embodiment of the composition of the invention, the poly (ethynylene phenylene ethynylene silylene) polymer included in the composition of the invention may be a polymer comprising at least one repeating unit, said repeating unit comprising two acetylenic bonds , at least one silicon atom, and at least one inert spacer group. Advantageously, said polymer also comprises, at the end of the chain, groups (Y) originating from a chain limiting agent. The term inert spacer group generally means a group which does not intervene, which does not react during crosslinking.

The repeating pattern of this polymer can be repeated n ₃ times.

Basically, the polymer, in this embodiment of the invention, comprises at least one repeating unit comprising at least one spacer group which does not intervene in a crosslinking process, to which the polymer can be subjected subsequently, in this embodiment of the invention.

The presence of such a spacer group in polymers of the poly (ethynylene phenylene ethynylene silylene) type is not mentioned in the prior art. Surprisingly, "this fundamental structural characteristic of the polymers according to this embodiment of the composition of the invention greatly improves the mechanical properties of the polymers, without significantly modifying their thermal properties, which remain excellent.

Without wishing to be bound by any theory, the role of the spacer is notably to constitute an internode knot of crosslinking sufficiently important to allow movements within the network.

In other words, the function of the at least one spacer group is to spatially separate the triple bonds of the polymer, whether these triple bonds belong to the same repeating unit or to two different repeating, consecutive patterns. The spacing between two triple bonds or acetylenic functions, provided by the spacer group, generally consists of linear molecules and / or of several aromatic nuclei linked, possibly separated by single bonds.

The spacer group, defined above, can be easily chosen by a person skilled in the art.

The choice of the nature of the spacer group also makes it possible to modulate the mechanical properties of the polymers of the invention, without significantly modifying the thermal properties.

The spacer group (s) may, for example, be chosen from the groups comprising several aromatic rings linked by at least one covalent bond and / or at least one divalent group, the polysiloxane groups, the polysilane groups, etc. ..

When there are several spacer groups, they are preferably two in number and they can be identical, or chosen from all the possible combinations of two or more of the groups mentioned above.

Depending on the spacer group chosen, the repeating pattern of the polymer, according to the second embodiment of the composition of the invention, may thus correspond to several formulas.

The polymer, according to this second embodiment of the invention, may be a polymer comprising a repeating unit of formula (V):

wherein the phenylene group of the central repeating unit can be in the form o, m or p; R represents a halogen atom (such as F, Cl, Br and I), an alkyl group (linear, or branched) having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms (such as methyl, ethyl, propyl, butyl, cyclohexyl), an alkoxy group having from 1 to 20 carbon atoms (such as methoxy, ethoxy, propoxy), an aryl group having from 6 to 20 carbon atoms (such as a group phenyl), an aryloxy group having 6 to 20 carbon atoms (such as a phenoxy group), an alkenyl group (linear, or branched) having 2 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 atoms carbon (such as vinyl, allyl, cyclohexenyl), an alkynyl group having 2 to 20 carbon atoms (such as ethynyl, propargyl), an amino group, an amino group substituted by one or two substituents having from 2 to 20 atoms carbon (such as dimethylamino, diethylamino, ethylmethylamino, methylphenylamino) or a silanyl ayan group t from 1 to 10 silicon atoms (such as silyl, disilanyl (-Si ₂ H ₅ ), dimethylsilyl, trimethylsilyl and tetramethyldisilanyl), one or more hydrogen atoms linked to carbon atoms of R which can be replaced by halogen atoms (such as F, Cl, Br and I), alkyl groups, alkoxy groups (such as methoxy, ethoxy and propoxy), aryl groups, aryloxy groups (such as 'a phenoxy group), amino groups, amino groups substituted by one or two substituents or silanyl groups'; R ₄ , R ₅ , R ₆ , R ₇ , identical or different, represent a hydrogen atom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, an aryl group having from 6 to 20 carbon atoms, an aryloxy group having from 6 to 20 carbon atoms, an alkenyl group having from 2 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, one or more of the hydrogen atoms linked to the carbon atoms of R ₄ , R ₅ , R ₆ and R ₇ may be replaced by atoms halogens, alkyl groups, alkoxy groups, aryl groups, aryloxy groups, amino groups, disubstituted amino groups or silanyl groups, examples of these groups have already been cited above for R, n is an integer from 1 to 4, and n _x is an integer from 1 to 10, preferably from 1 at 4, this repeating pattern is generally repeated n ₃ times with n ₃ being an integer, for example from 2 to 100.

Or else the polymer, according to the second embodiment of the composition of the invention, could be a polymer comprising a repeating unit of formula:

in which the phenylene group can be in the form o, m or p and R, R ₄ , R ₆ and n have the meaning already given above and n ₂ is an integer from 2 to 10.

This repeating pattern is generally repeated n ₃ times, with n ₃ being an integer, for example from 2 to 100.

Or else the polymer, according to this second embodiment of the composition of the invention, could be a polymer comprising a repeating unit of formula:

in which R ₄ and R ₆ have the meaning already given above, and R ₈ represents a group comprising at least two aromatic rings comprising, for example from 6 to 20 C, linked by at least one covalent bond and / or at least a divalent group, this repeating pattern is generally repeated n ₃ times, with n ₃ , as defined above.

Or else the polymer, according to this second embodiment of the composition of the invention, could be a polymer comprising a repeating unit of formula:

in which R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and n _α have the meaning already given above, this repeating pattern can likewise be repeated n ₃ times.

Finally, the polymer, according to this second embodiment of the composition of the invention, may be a polymer comprising a repeating unit of formula:

in which R ₄ , R _{6 /} R ₈ and n ₂ have the meaning already given above, this motif being able to be repeated n ₃ times.

In particular, in formulas (III), (IV) and (V) above, R ₈ represents a group comprising at least two aromatic rings separated by at least one covalent bond and / or a divalent group.

The group R ₈ can, for example, be chosen from the following groups:

where X represents a hydrogen atom or a halogen atom (F, Cl, Br, or I).

Alternatively, the polymer according to this second embodiment of the invention may comprise several different repeating units, comprising at least one inert spacer group.

Said repeating units are preferably chosen from the repeating units of formulas (V), (Va), (Vb), (Vc) and (Vd), already described above.

Said repeating patterns are repeated respectively Xi, x ₂ , x ₃ , x ₄ and x ₅ times, where x _x , x ₂ , x ₃ , x ₄ and x ₅ generally represent whole numbers from 0 to 100,000, provided that at least two of

Xi, x ₂ , x ₃ , x ₄ and x ₅ are different from 0.

This polymer with several different repeating units can optionally comprise, in addition, one or more repeating units not comprising an inert spacer group, such as a unit of formula

(Fr):

This pattern is usually repeated x ₆ times, with x ₆ representing an integer from 0 to 100,000.

A preferred polymer corresponds, for example, to the formula:

(Vf)

where Xi, x ₂ , x ₃ , Xε are as defined above, provided that two of Xi, x ₂ and x ₃ are different from 0. The polymers according to this second embodiment of the composition of the invention advantageously comprise (end) groups (Y) originating from a chain limiting agent, which makes it possible to control, to modulate their length, their molecular mass, and therefore their viscosity. The polymers, according to this second embodiment of the composition of the invention, compared to the polymers of document EP-B1-0 617 073, are distinguished, in particular, fundamentally due to the presence of at least one spacer group in the repeating pattern.

The polymers of this second embodiment of the present invention can also be distinguished due to the presence at the chain end of groups Y derived from a chain-limiting agent.

These structural differences have very little influence on the advantageous properties of these polymers, in particular the thermal stability properties of the polymer, which are hardly affected.

On the other hand, the mechanical properties, such as the deformation capacity or the breaking stress, are greatly improved by the presence of the spacer group or groups. In addition, the advantageous presence at the end of the chain of a chain limiting group has precisely the effect that the polymer of the invention in this second embodiment has a length and therefore a determined molecular weight, perfectly defined. Consequently, the polymer according to this second embodiment of the composition of the invention also advantageously has perfectly defined and modular rheological properties.

The nature of the possible chain-limiting group Y depends on the nature of the chain-limiting agent. chain from which it is derived, Y could represent a group of formula:

wherein R "'has the same meaning as R and can be the same or different from the latter, and n' has the same meaning as n and can be the same or different from the latter.

Y could also represent a group of formula (VIII):

Ri

If R ₂ (VIII)

: * 3

in which R _lt R ₂ and R ₃ which may be identical or different have the meaning already given above.

The molecular weight of the polymers according to the invention is - because they comprise a chain limiter group - perfectly defined, and the length of the polymer and therefore its molecular weight can be easily controlled by metered additions of chain limiter in the reaction mixture reflecting by varying proportions of Y chain limiting group in the polymer.

Thus, the molar ratio of the Y groups, chain limiters, at the end of the chain to repeating units of the ethynylene phenylene ethynylene silylene type is generally from 0.01 to 1.5. Preferably, this ratio is 0.25 to 1.

Similarly, according to the invention, the molar proportion of the Y groups, chain limiters, if any, at the end of the chain is generally from 1 to 60 and preferably from 20 to 50% of the polymer used in this second embodiment. of the composition according to the invention.

The number-average molecular weight of the polymers used in this second embodiment of the composition according to the invention is generally from 400 to 100,000, and the weight-average molecular weight is 500 to 1,000,000.

The number average molecular weight of the polymers according to the invention is, because they comprise a perfectly defined chain limiting group, and is generally from 400 to 10,000 and the weight average molecular weight is from 600 to 20,000.

These masses are determined by gel permeation chromatography (GPC) from a polystyrene calibration.

Thanks to the fact that the polymer, in this second embodiment, advantageously has chain-limiting groups, the control of the molecular mass of the polymers which is generally situated in the above-mentioned range, allows perfect control of the viscosity of the polymers.

Thus, the viscosities of the polymers used in this second embodiment of the composition according to the invention are in a range of values from 0.1 to 1000 mPa.s, for temperatures ranging from 20 to 160 ° C, within the range of masses mentioned above.

The viscosity also depends on the nature of the groups carried by the aromatic rings and the silicon. These viscosities which cannot be obtained with the polymers of the prior art are fully compatible with the conventional techniques for preparing composites. According to the invention it is thus possible to modify at will depending on technological constraints ^• implementation of the composite, the polymer viscosity.

The viscosity is also linked to the glass transition temperature (Tg). The glass transition temperature of the polymers according to the invention will therefore generally be from -250 to + 10 ° C., which is much lower than the glass transition temperature of the polymers of the prior art. The poly (ethynylene phenylene ethynylene silylene) used in the compositions of the invention can be prepared by any known process for the preparation of these polymers, for example the processes described in documents EP-B1-0 617 073 and FR -A-2 798 662. In particular, the polymers (I) and (la) can be prepared by the process of document FR-A-2 798 662 and the polymers with inert spacer group can be prepared by the processes analogous to those of the documents EP-B1-0 617 073, and FR-A-2 798 662 if they include chain limiting groups.

A first process for the preparation of a polymer included in the composition according to the invention, preferably of determined molecular mass, optionally bearing, at the end of the chain, groups derived from a chain-limiting agent, said polymer corresponding in particular to the formula (V), (Va),

(Vb), (Vc) or (Vd), given above, includes the reaction of a GRIGNARD reagent of general formula:

or general formula

in which the phenylene group (formula (IX)) may be in the form o, m or p, and R, R ₈ and n have the meaning indicated above, and X _x represents a halogen atom such as Cl, Br, F, or I (from preferably Xi is Cl), optionally mixed with a chain-limiting agent, for example of the formula:

Y - MgXi (XI)

X _x having the meaning already given above, and Y is a group chosen from the groups of formula:

wherein R "'has the same meaning as R and may be the same or different from the latter, and n' has the same meaning as n and may be the same or different from the latter; with a dihalide

(dihalosilane or dihalosiloxane) of formula (XIII) (a, b, or c):

(XIIIa)

or

(XIIIb)

in which Ri, R ₂ , R ₃ and R _{4 are} identical or different, Xi, n _x and n ₂ have the meaning already indicated above, i preferably being Cl, in the presence of an aprotic solvent, then a step d hydrolysis to give the final polymer, respectively of formula (V), (Va), (Vb), (Vc), (Vd).

That is to say that the polymers of respective formulas (V), (Va), (Vb), (Vc), or (Vd) are obtained respectively by reaction of (IX) and (XlIIa) •; (IX) and (XlIIb); (X) and respectively (XIIIc), (XlIIa), and (XlIIb). It is noted that if the reaction involves a chain limiter, then the hydrolysis is carried out directly.

A second process for the preparation of a type polymer of poly (ethynylene phenylene ethynylene silylene), preferably of determined molecular mass, optionally bearing at the end of the chain groups derived from a chain limiting agent, said polymer corresponding in particular to the formula (V), (Va), (Vb), (Vc), (Vd), given above, comprises the reaction of a compound of formula (XIV):

or general formula

-Rs (XV)

in which the phenylene group (general formula (XIV)) may be in the form o, m, or p and R and n have the meaning already indicated above, optionally in admixture with a chain-limiting agent, for example, of formula (XVI):

wherein R '''has the same meaning as R and can be the same or different from the latter, and n' has the same meaning as n and can be the same or different from the latter with a compound of formula (XVII) (a , goat) :

(XVIIa)

or

or

H- - -H (XVIIc)

R ₃

in which R, R ₂ , R ₃ , R ₄ which may be the same or different and ni and n ₂ have the meaning already mentioned above, in the presence of a basic metal oxide to give the final compound of formula (V ), (Va), (Vb), (Vc) or (Vd), respectively. That is to say that the polymers of respective formulas (V), (Va), (Vb), (Vc) or (Vd) are obtained respectively by reaction of (XIV) and (XVIIa); (XIV) and (XVIIb); (XVII) and respectively (XVIIc), (XVIIa) and (XVIIb).

According to the invention, and surprisingly, the control of the masses of the polymers according to the invention can preferably be obtained by adding to the reaction medium a reactive species also called chain-limiting agent which blocks the reaction of polymerization without affecting the overall yield of the reaction.

Whether in the first process or in the second process, the length of the polymer and therefore its molecular weight, and consequently, its viscosity are in direct correlation with molar percentage of chain-limiting agent. This molar percentage is defined by the mole ratio of the chain-limiting agent to the total of the moles of chain-limiting agent and of diacetylene compounds of formula (IX), or (X), or (XIII) or (XV ) x 100. This percentage can range from 1 to 60%, preferably from 20 to 50%.

The invention also relates to the cured product capable of being obtained by heat treatment of the composition described above at a temperature generally of 50 to 500 ° C., optionally in the presence of a catalyst.

Finally, the invention also relates to a composite matrix comprising the polymer described above. In detail, the process for preparing a polymer of the poly (ethynylene phenylene ethynylene silylene) type can be that described in document EP-B1-0 617 073 in the case where the polymer does not have a chain, or it may be a process which is substantially similar to that described in document EP-B1-0 617 073 and which is that described in document FR-A-2 798 662. This latter process called “First preparation process” according to the invention differs from the process of document EP-B1-0 617 073 by the incorporation into the mixture of a chain-limiting agent, by the final treatment of the polymers and optionally by the molar ratio organomagnesium reagents and dichlorosilane. We can therefore, with respect to the conditions of this process, refer to this document EP-B1-0 617 073 which is incorporated herein by reference as well as to document FR-A-2 798 662 which is also incorporated in this for your reference.

The GRIGNARD reagents of formula (IX) used in the first preparation process, according to the invention, are in particular those described in document EP-B1-0 617 073 on pages 5 to 7 (Formulas (3) and ( 8) to (20)). The GRIGNARD reagents of formula (X) are, for example, chosen from the compounds obtained from formulas (VI) to (VId).

The chain limiting agent of formula (XI) can be a monoacetylene organomagnesium compound of formula:

R "', i and n' have already been defined above.

Examples of the monohalosilane, intervening for example in the step preceding the hydrolysis, are given in patent EP-B1-0 617 073 on page 9 (formula (5)).

Examples of the monoacetylene compounds from which the monoacetylene organomagnesiums are derived

(XI) are the following: phenyl-acetylene,

4-ethynyltoluene 4-ethynylbiphenyl, 1-ethynyl 4-methoxybenzene.

The GRIGNARD reagent (IX) or (X), in admixture with the chain-limiting compound corresponding to the above formula, is reacted with a dihalogenosilane, reproduced in one of the general formulas (XlIIa) to (XIIIc) .

Examples of such dihalosilanes (for example, those of formula (XlIIb)) are the dichlorosilanes described on pages 7 to 9 of the patent

EP-B1-0 617 093 and respond in particular to formulas (21) to (26) given in this document.

The conditions of the polymerization reaction such as the solvent, the duration of the reaction, the temperature, etc. (excluding "post-treatment") are substantially the same as those described in document EP-B1- 0 617 073 to which reference is made in particular on page 14. The only differences in this actual polymerization step relate to the addition of an additional chain-limiting reagent. The reaction conditions are moreover substantially the same.

However, and according to the invention, preferably, in the advantageous case where the ratio of the number of acetylenic functions to the number of halogen functions carried by the silane is used, must be as close as possible to 1, and preferably 0.9 to 1.1. The molar ratio of phenyl-acetylene to diethynylbenzene is preferably between 0.01 and 1.5 and ideally between 0.25 and 1

(percentage from 1 to 60%). This also applies to the variant of the first process in which the chain limiter is a monohalogenosilane.

According to the invention, due to the fact that a chain limiter is used, following the polymerization reaction, a final hydrolysis step is carried out directly, so there is no step compared to the analogous process of l prior art in particular in the case where the chain limiter is an organomagnesium. In fact, in document EP-B1-0 617 073, post-treatment of the already prepared polymer, the molecular mass of which is fixed, is carried out with a monohalosilane and then hydrolysis. It should be noted that in this case the monohalosilane does not play the role of chain limiter since it is not on the contrary of the present invention included in the starting reaction mixture and that its action has no influence on the molecular weight of the polymer.

According to the invention, at the end of the reaction, the polymer is hydrolyzed by a volume for example of 0.1 to 50 ml per gram of polymer of an acid solution, for example approximately 0.01 to 10 N of hydrochloric acid or d 'sulfuric acid.

The ideal solvent is tetrahydrofuran. In this case, the reaction mixture is then decanted and the solvent of the organic phase is substituted with a volume for example of 0.1 to 100 ml per gram of polymer and ideally of 1 to 10 ml per gram of polymer for any type of solvent immiscible with water, such as xylene, toluene, benzene, chloroform, dichloromethane or alkane with more than 5 carbons. In the case of a reaction carried out in a water immiscible solvent, this step can be omitted. The organic phase is then washed for example from 1 to 5 times and preferably 2 to 3 times with a volume of water, for example from 0.1 to 100 ml per gram of polymer and ideally from 1 to 10 ml per gram of polymer , so as to neutralize the organic phase and extract from it all the impurities such as magnesium and halogen salts. The pH of the organic phase should preferably be between 5 and 8 and ideally between 6.5 and 7.5. After evaporation of the solvent, the polymer is dried under a vacuum of between 0.1 and 500 mbar at a temperature between 20 and 150 ° C for a time between 15 minutes and 24 hours. The second process for preparing the polymers according to the invention is a process making call for dehydrogenation in the presence of a basic metal oxide.

Such a process differs essentially from the analogous process described in documents [1] and [4] as well as in document EP-B1-0 617 073 only in that a chain limiting agent is added to the reaction mixture.

The reaction mixture comprises a compound of formula (XIV) for example: 1, 3-diethylnylbenzene or (XV), and a chain-limiting agent which in this second process is a monoacetylene (XVI) analogous to that already described above for the first process.

The compound (XIV), or (XV), in mixture with the chain-limiting agent reacts with a dihydrosilane of formula (XVIIa) to (XVIIc).

The basic metal oxide used is preferably chosen from alkali metal, alkaline earth metal oxides, lanthanide oxides, scandium, yttrium, thorium, titanium, zirconium, hafnium, copper, zinc, cadmium oxides and their mixtures. .

Examples of such oxides are given in document EP-B1.-0 617 073 on pages 16 and 17 to which explicit reference is made here. These oxides can be subjected to an activation treatment as described in patent EP-B1-0 617 073.

The cured products prepared by heat treatment of the compositions according to the invention are for example produced by first mixing the polymer and the “plasticizer” compound (in liquid form) and then by melting this mixture; or well, first dissolving the polymer and the plasticizing compound in a suitable solvent.

Then, the composition is optionally put in the desired form, and it is heated in a gaseous atmosphere of air, nitrogen or an inert gas such as argon or helium.

The temperature of the treatment generally ranges from 50 to 500 ° C, preferably from 100 to 400 ° C and more preferably from 150 to 350 ° C, and the heating is generally carried out for a period of one minute to 100 hours.

Due to the similar structure of the polymers according to the invention and of the polymers of document EP-B1-0 617 073, their hardening process is substantially identical and reference may be made to this document on page 17, as well as in document FR-A-2 798 622, for more details.

The composition of the invention, that is to say the composition comprising the mixture of at least one poly (ethynylene phenylene ethynylene silylene) polymer and at least one compound capable of exerting a plasticizing effect in the mixture once the latter has hardened, in other words, the “plasticized” poly (ethynylene phenylene ethynylene silylene) resin can also be hardened at temperatures below the thermal crosslinking temperatures, under the action of a catalyst for the Diels reactions. Help and hydrosillylation. In particular, platinum-based catalysts, such as H ₂ PtCl ₆ , Pt (DVDS), Pt (DVDS), Pt (dba), where DVDS represents divinyldisiloxane, TVTS the trivinyltrisiloxane and dba, dibenzilidene acetone; and transition metal complexes, such as Rh ₆ (CO) ι ₆ or Rh ₄ (CO) ι _{2 /} ClRh (PPh ₃ ), Ir (CO) ι ₂ and Pd (dba) can be used for the catalysis of hydrosilylation reactions.

The catalysts based on transition metal pentachloride, such as TaCl ₅ , NbCl ₅ or MoCl ₅ will in turn be advantageously used to catalyze reactions of the Diels Aider type. The catalysis of these reactions makes it possible to use “plasticizing” compounds of low molecular mass and therefore of low boiling point. These compounds will be easily chosen by a person skilled in the art from the compounds capable of exerting a plasticizing effect mentioned above. These “plasticizers” will advantageously be used to lower the viscosity of the mixture before processing.

The nature and structure of the hardened materials or products obtained depend on the polymer (s) of poly (ethynylene phenylene ethynylene silylene) and on the compound capable of exerting a plasticizing effect (which may also be a polymer) used.

It is thus possible to produce cured polymer-polymer composite products or materials, consisting of a matrix of the polymer within which are dispersed nodules consisting of the compound exerting a plasticizing effect, such as a polymer (“plasticizer”) added . This scenario is encountered in particular when the polymer and the plasticizing compound such as a polymer, used, are not miscible. The proportion of each constituent conditions the nature of the matrix and the nodules.

It is also possible to obtain a material made up of two distinct matrices constituted respectively by the polymer and the compound exerting a plasticizing effect whose networks are interpenetrated so that no phase dissociation is perceptible. This scenario is notably encountered when the polymer (s) and the “plasticizer” compound, such as a polymer used in the formulation are perfectly miscible and when the polymer (s) and the compound, such as a polymer, simultaneously form hardened networks. Finally, the hardened material can also consist of a single network. This scenario is encountered in particular when the polymer and the compound such as a polymer present possibilities of reaction with each other. In particular, reactive "plasticizing" compounds, such as polymers functionalized with acetylenic functions or functions with hydrogenated silanes, are capable of reacting thus.

The preparation of organic matrix composites comprising the polymer of the invention can be done by numerous techniques. Each user adapts it to their constraints. The principle is generally always the same: namely, coating of a textile reinforcement with the resin, then crosslinking by heat treatment comprising a speed of temperature rise of a few degrees / minute, then a plateau close to the crosslinking temperature.

It should be noted that in the case described above, where one is in the presence of a cured polymer-polymer composite material, the presence of a textile reinforcement is not necessary.

The invention will now be described with reference to the following example, given by way of illustration and not limitation.

Example

Plasticization of poly (methylene silylene ethynylene phenylene ethynylene) with hexamethyltrisiloxane.

1. Principle

Poly (methylene silylene ethynylene phenylene ethynylene) is obtained by conventional magnesian coupling reactions between a dihalogenated silane and the difunctional GRIGNARD reagent of diethynylbenzene.

The viscosity of this polymer is adjusted by the introduction of phenyl-acetylene, in accordance with document FR-A-2 798 662 cited above. The plasticization of poly (methylene silylene ethynylene phenylene ethynylene) is obtained by reaction with the trisiloxane compound, that is to say hexamethyltrisiloxane, under the catalytic effect of a platinum-based catalyst. 2. Implementation

To 10 g of poly (methylene silylene ethynylene phenylene ethynylene), 2 g of hexamethyltrisiloxane and 50 mg of a THF solution containing H ₂ PtCl ₆ at a concentration of 20 g / 1 are added. The homogeneous mixture thus obtained is maintained at ambient temperature, until gelation. The gel can then be brought to temperature according to the standard conditions of this type of unplasticized polymers.

After post-curing under temperature conditions adapted to the applications, a hardened material is obtained, the mechanical properties of which are improved compared to the materials obtained without plasticizer.

By way of example, the hardened materials obtained according to the above example according to the invention have in particular an elongation at break three times greater than that which can be measured on an unplasticized material not in accordance with the invention.

REFERENCES

[1] "New Highly Heat-Resistant Polymers containing Silicon: Poly (silyleneethynylenephenylene éthynylène) s" by ITOH M., INOUE K., I ATA K., MITSUZUKA M. and KAKIGANO T., Macromolecules, 1997, 30, pp. 694 - 701.

[2] CORRIU Robert J. P. et al., Journal of polymer science: Part C: Polymer Letters, 1990, 28, pp. 431 - 437.

[3] “Copper (I) chloride catalyzed cross dehydrocoupling reactions between silanes and ethynyl compounds. A new method for the copolymerization of silanes and alkynes "by Liu H. Q.; HARROD J. F. The Canadian Journal of Chemistry, 1990, vol. 68, pp. 1,100 - 1,105.

[4] "A novel synthesis and extremely high Thermal stability of

Poly [(phenylsilylene) - (ethynylene-1, 3-phenylene ethynylene)] ”by ITOH M., INOUE K., IWATA K., MITSUZUKA M., KAKIGANO T.; Macromolecules, 1994, 27, pp. 7,917 - 7,919.

[5] KUROKI S.; OKITA K.; KAKIGANO T.; ISHIKAWA J.; ITOH M.; Macromolecules, 1998, 31, 2 804 - 2 808.

Claims

1. Composition comprising the mixture of at least one poly (ethynylene phenylene ethynylene silylene) polymer and at least one compound capable of exerting a plasticizing effect in the mixture, once the latter has hardened.

2. Composition according to claim 1, in which said compound capable of exerting a plasticizing effect is chosen from organic and inorganic polymers and resins.

3. Composition according to claim 2, in which the organic polymers are chosen from thermoplastic polymers and thermosetting polymers.

4. Composition according to claim 3, in which the thermoplastic polymers are chosen from fluorinated polymers.

5. Composition according to claim 3, in which the thermosetting polymers are chosen from epoxy resins, polyimides

(poly (bismaleimides)), polyisocyanates, formophenolic resins, silicones or polysiloxanes, and all other aromatic and / or heterocyclic polymers.

6. Composition according to any one of claims 1 to 5, in which the compound such as a polymer capable of exerting a plasticizing effect and the poly (ethynylene phenylene ethynylene silylene) are not miscible with each other .

7. Composition according to any one of claims 1 to 5, in which the compound such as a polymer capable of exerting a plasticizing effect and the poly (ethynylene phenylene ethynylene silylene) have partial miscibility with each other .

8. Composition according to any one of claims 1 to 5, in which the compound such as a polymer capable of exerting a plasticizing effect and the poly (ethynylene phenylene ethynylene silylene) are perfectly miscible with one another.

9. Composition according to any one of claims 1 to 8, in which the compound capable of exerting a plasticizing effect is a reactive compound.

10. Composition according to claim 9, wherein said compound capable of exerting a plasticizing effect comprises at least one reactive function chosen from acetylenic functions and hydrogenated silane functions.

11. Composition according to any one of claims 9 and 10, in which the reactive compound is chosen from hydrogenated silicone polymers and resins and / or comprising at least one acetylenic function.

12. Composition according to claim 11, in which the reactive compound is chosen from polymers and resins having the following formulas:

where Ri and R ₂ , identical or different, represent an alkyl group of 1 to 10 C and in particular a methyl group, and where one or more of the hydrogen atoms carried by the silicon atoms and the carbon atoms can be replaced by a reactive group, such as an acetylene group;

H- ^• ib)

where Ri, R ₂ and R ₃ , identical or different, represent an alkyl group of 1 to 10 C and in particular a methyl group, and where one or more of the hydrogen atoms carried by the silicon atoms and the carbon atoms can be replaced by a reactive group, such as an acetylene group; 6516

63

where RI represents an alkyl group of 1 to 10 C and in particular the methyl group, and where one or more of the hydrogen atoms carried by the silicon atoms and the carbon atoms can be replaced by a reactive group, such as a acetylene group;

where Ri, R ₂ and R ₃ , identical or different, represent an alkyl group of 1 to 10 C and in particular the methyl group and where one or more of the hydrogen atoms carried by the silicon atoms and the carbon atoms can be replaced by a reactive group, such as an acetylene group, x and y represent the molar fraction of each of the units concerned and are liable to vary between 0 and 1.

13. Composition according to any one of claims 1 to 12, in which the molar mass of the compound (s) capable of exerting a plasticizing effect is between 200 and 10 ⁶ g / mol.

14. Composition according to any one of claims 1 to 13, in which the amount of compound capable of exerting a plasticizing effect is between 0.1 and 200% and preferably between 10 and 50% of the mass of the poly ( ethynylene phenylene ethynylene silylene).

15. Composition according to any one of claims 1 to 14, in which the poly (ethynylene phenylene ethynylene silylene) polymer corresponds to the following formula (I):

or to the following formula (la)

in which the phenylene group of the central repeating unit can be in the form o, m or p; R represents a halogen atom (such as F, Cl, Br and I), an alkyl group (linear, or branched) having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms (such as methyl, ethyl, propyl, butyl, cyclohexyl), an alkoxy group having from 1 to 20 carbon atoms (such as methoxy, ethoxy, propoxy), an aryl group having from 6 to 20 carbon atoms (such as a group phenyl), an aryloxy group having 6 to 20 carbon atoms (such as a phenoxy group), an alkenyl group (linear, or branched) having 2 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 atoms carbon (such as vinyl, allyl, cyclohexenyl), an alkynyl group having 2 to 20 carbon atoms (such as ethynyl, propargyl), an amino group, an amino group substituted by one or two substituents having from 2 to 20 atoms carbon (such as dimethylamino, diethylamino, ethylmethylamino, methylphenylamino) or a silanyl ayan group t from 1 to 10 silicon atoms (such as silyl, disilanyl (-Si ₂ H ₅ ), dimethylsilyl, trimethylsilyl and tetramethyldisilanyl), one or more hydrogen atoms linked to the carbon atoms of R can be replaced by d atoms halogen

(such as F, Cl, Br and I), alkyl groups, alkoxy groups (such as methoxy, ethoxy and propoxy), aryl groups, aryloxy groups (such as a phenoxy group), amino groups, amino groups substituted with one or two substituents or silanyl groups; n is an integer from 0 to 4 and q is an integer from 1 to 40; R 'and R'', identical or different, represent a hydrogen atom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an alkoxy group having from 1 to 20 atoms carbon, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 carbon atoms , an alkynyl group having from 2 to 20 carbon atoms, one or more of the hydrogen atoms linked to the carbon atoms of R 'and R''may be replaced by halogen atoms, alkyl groups, alkoxy groups , aryl groups, aryloxy groups, amino groups, disubstituted amino groups or silanyl groups, examples of these groups have already been cited above for R; and Y represents a group derived from a chain-limiting agent.

16. Composition according to claim 15, in which the polymer corresponds to formula (I) and Y represents a group of formula (III):

in which R "'has the same meaning as R and may be the same or different from the latter, and does not have the same meaning as n and may be the same or different from the latter.

17. Composition according to claim 15, in which the polymer corresponds to formula (la) and Y represents a group of formula (IV):

(IV)

_{: ι} ",

wherein R ', R "and R"' which may be the same or different have the meaning already given in claim 15 and claim 16.

18. Composition according to claim 15, in which the polymer corresponds to the following formula:

where q is an integer from 1 to 40.

19. The composition as claimed in claim 15, in which the polymer is a polymer of determined molecular mass, capable of being obtained by 68 hydrolysis of the polymers of formula (la) and corresponding to the following formula (Ib):

in which R, R ', R' ', n and q have the meaning already given in claims 15 and 18.

20. The composition as claimed in claim 15, in which the polymer has a molar ratio of the end groups Y to the repeating units ethynylene phenylene ethynylene silylene from 0.01 to 1.5, preferably from 0.25 to 1.

21. The composition as claimed in claim 15, in which the molar proportion of the chain end Y groups is generally from 1 to 60 and preferably from 20 to 50% of the polymer of formula (I) or (la).

22. Composition according to Claims 15 and 19, in which the number-average molecular mass of the polymers (I), (la) and (Ib) is from 400 to 10,000, preferably from 400 to 5,000, and the mass weight average molecular is 600 to 20,000, preferably 600 to 10,000.

23. Composition according to any one of claims 1 to 14, in which the polymer of 76

69 poly (ethynylene phenylene ethynylene silylene) is a polymer comprising at least one repeating unit, said repeating unit comprising two acetylenic bonds, at least one silicon atom, and at least one inert spacer group.

24. The composition according to claim 23, wherein said polymer further comprises groups (Y) derived from a chain-limiting agent.

25. The composition of claim 23, wherein said inert polymer spacer group does not intervene during crosslinking.

26. The composition as claimed in claim 23, in which said polymer spacer group (s) is (are) chosen from groups comprising several aromatic rings linked by at least one covalent bond and / or at least a divalent group, polysiloxane groups, polysilane groups and all possible combinations of two or more of these groups.

27. The composition as claimed in claim 23, in which said polymer is a polymer comprising a repeating unit of formula (V):

76516

70 in which the phenylene group of the central repeating unit can be in the form o, m or p; R represents a halogen atom (such as F, Cl, Br and I), an alkyl group (linear, or branched) having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms (such as methyl, ethyl, propyl, butyl, cyclohexyl), an alkoxy group having from 1 to 20 carbon atoms (such as methoxy, ethoxy, propoxy), an aryl group having from 6 to 20 carbon atoms (such as a group phenyl), an aryloxy group having 6 to 20 carbon atoms (such as a phenoxy group), an alkenyl group (linear, or branched) having 2 to 20 carbon atoms, a cycloalkenyl group having 3 to 20 atoms carbon (such as vinyl, allyl, cyclohexenyl), an alkynyl group having 2 to 20 carbon atoms (such as ethynyl, propargyl), an amino group, an amino group substituted by one or two substituents having from 2 to 20 atoms carbon (such as dimethylamino, diethylamino, ethylmethylamino, methylphenylamino) or a silanyl ayan group t from 1 to 10 silicon atoms (such as silyl, disilanyl (-Si ₂ H ₅ ), dimethylsilyl, trimethylsilyl and tetramethyldisilanyl), one or more hydrogen atoms linked to the carbon atoms of R can be replaced by d atoms halogens (such as F, Cl, Br and I), alkyl groups, alkoxy groups (such as methoxy, ethoxy and propoxy), aryl groups, aryloxy groups (such as a phenoxy group), amino groups , amino groups substituted with one or two substituents or silanyl groups; R, R _Ξ , R ₆ , R ₇ , identical or different, 76516

71 represents a hydrogen atom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, an aryl group having from 6 with 20 carbon atoms, an aryloxy group having from 6 to 20 carbon atoms, an alkenyl group having from 2 to 20 carbon atoms, a cycloalkenyl group having from 3 to 20 carbon atoms, an alkynyl group having from 2 to 20 carbon atoms, one or more of the hydrogen atoms linked to the carbon atoms of R ₄ , R ₅ , R ₆ and R ₇ may be replaced by halogen atoms, alkyl groups, alkoxy groups, aryl groups , aryloxy groups, amino groups, disubstituted amino groups or silanyl groups, examples of these groups have already been cited above for R, n is an integer from 1 to 4, and ni is an integer of 1 to 10, preferably 1 to 4, this repeating pattern is generally r pété n ₃ times with n ₃ being an integer, for example from 2 to 100.

28. The composition according to claim 23, wherein said polymer is a polymer comprising a repeating unit of formula:

76516

72

in which the phenylene group may be in the form o, m or p and R, R ₄ , R _s and n have the meaning already given in claim 27 and n ₂ is an integer from 2 to 10.

29. The composition according to claim 23, wherein said polymer is a polymer comprising a repeating unit of formula:

in which R ₄ and R ₆ have the meaning already given above, and R ₈ represents a group comprising at least two aromatic rings comprising, for example from 6 to 20 C, linked by at least one covalent bond and / or at least a divalent group.

30. The composition according to claim 23, wherein said polymer is a polymer comprising a repeating unit of formula:

76516

73 in which R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and ₂ have the meaning already given in claims 27 and 29.

31. A composition according to claim 23, in which said polymer is a polymer comprising a repeating unit of formula:

in which R ₄ , R ₆ , Rs and n ₂ have the meaning already given in claims 27, 28 and 29.

32. Composition according to any one of claims 27 to 31, in which the group R ₈ of the polymer is chosen from the following groups:

076516

74

where X represents a hydrogen atom or a halogen atom (F, Cl, Br, or I).

33. Composition according to any one of claims 23 to 32, in which the polymer comprises a repeating unit repeated n ₃ times, with n ₃ being an integer, for example from 2 to 100.

34. The composition of claim 23, wherein the polymer comprises several different repeating units comprising at least one inert spacer group.

35. A composition according to claim 34, in which said repeating units of the polymer, comprising at least one inert spacer group - are chosen from the repeating units of formulas (V), (Va), (Vb), (Vc) and (Vd), defined respectively in claims 27, 28, 29, 30 and 31.

36. Composition according to claim 35, in which the said repeating units of the polymer are repeated respectively x ***., X ₂ , x ₃ , x ₄ and x ₅ times, xi, x ₂ , x ₃ , x ₄ and x ₅ representing whole numbers from 0 to 100,000, provided that at least two of x _i7 x ₂ , x ₃ , x ₄ and x ₅ are different from 0.

37. Composition according to any one of claims 23 to 36, in which the polymer further comprises one or more repeating units not comprising an inert spacer group.

38. A composition according to claim 37, in which said repeating unit of the polymer which, not comprising an inert spacer group, corresponds to the formula:

39. Composition according to claim 37 or

38, in which said repeating unit of the polymer, not comprising an inert spacer group, is repeated Xth times, x ₆ representing an integer from 0 to 100,000.

40. Composition according to any one of claims 34 to 39, in which the polymer corresponds to the formula:

41. A composition according to any one of claims 34 to 39, in which the polymer has a number average molecular weight of 400 to 10,000 and a weight average molecular weight of 500 to 1,000,000.

42. Cured product capable of being obtained by heat treatment at a temperature of 50 to 500 ° C of the composition according to any one of claims 1 to 41, optionally in the presence of a catalyst, such as a catalyst for the reactions Helping Diels and Hydrosillylation.

43. The cured product according to claim 42, consisting of a matrix of the poly (ethynylene phenylene ethynylene silylene) polymer within which are dispersed modules consisting of the compound exerting a plasticizing effect.

44. The cured product according to claim 42, consisting of two distinct matrices constituted respectively by the polymer and the compound whose networks are interpenetrated.

45. The cured product according to claim 42, consisting of a single network.

46. Matrix for composite comprising the composition according to any one of claims 1 to 41.