RU2293746C1 - Functional polymetallosiloxanes - Google Patents

Abstract

FIELD: organosilicon polymers.

SUBSTANCE: invention provides novel functional polymetallosiloxanes that could find use in modifying polymers and imparting new properties to materials. Novel functional polymetallosiloxanes are characterized by having statistic cyclolinear structure depicted by general formula I:

(I), where M represents bi- or trivalent metal selected from series: Zr, Zn, Fe(II), Fe(III), Ce, Cu, Cr, Sm, Eu and t corresponds to valence of metal; Alk is substituent CH₃, C₆H₅, or NH₂ (CH₃)₃-; R' is substituent CH₂=CH-; n=0 or 1; R" represents at least one unit from following series of units: -OSiR'n(OAlk)_2-n, -OSiR'R"(OAlk)_1-nO_1/2, and -OSiR'R"_n(O_1/2-)_2-n; k ranges from 2 to 500; and A represents at least one ordinary bond and/or Alk. Functional polymetallosiloxanes are prepared via hydrolytic polycondensation of functional metallosiloxane selected from those having general formula II:

(II), where M, m, R', R", A;k, and n are as defined above, whereas metallosiloxane-to-water molar ratio ranges from 1:0.05 to 1:1.

EFFECT: expanded synthetic possibilities in organosilicon polymer area.

24 cl, 3 dwg, 1 tbl, 9 ex

Description

The invention relates to the field of chemical technology of organosilicon compounds and may find industrial application in the production of modifiers, in particular thermal stabilizers, of various polymers. More specifically, the invention relates to new functional polymetallosiloxanes.

The use of metals, in particular salts of organic acids, as thermostabilizing additives to polymer compositions, in particular organosiloxane polymers, is based on their ability to inhibit free radical chain processes occurring during thermal oxidation, deactivating the formation of free radicals or intermediate oxidation products (US patent 3142655, 1964; ed. Certificate of the USSR No. 369131, 1973). However, for effective thermal stabilization of polymers, it is necessary to solve a number of problems, such as, for example, the possibility of homogeneous introduction of the additive, the absence of its volatility at high temperatures, bringing dispersion of stabilizing additives to nanoscale, including in rubber compounds, etc.

The addition of organic salts of a number of metals to polymer compositions as thermostabilizing additives is known (see, for example, US Pat. Nos. 4,193,885, 1980; 4,528,313, 1985). In the descriptions of the patents considered a fairly wide range of metals. However, the poor compatibility of such compounds and polymer matrices and the problems of their dispersion in the polymer significantly reduce their effectiveness and complicate the process of introducing additives.

Heat-resistant and partially functional metallosiloxane compounds are known, obtained by the interaction of 1,4-trimethylsiloxybenzene and sodium hydroxide, followed by the exchange of sodium for aluminum, zinc and calcium (J. Chem. Soc., Dalton trans., 1999, p. 4535-4540). These compounds have poor solubility, contain water residues, and their structure is non-deterministic.

Known oligomeric and polymeric organosilicon compounds containing metal atoms in the structure, effective as thermostabilizing additives (US patents 6336026, 6297302, 6297302, US 6037092). Such compounds are prepared by reacting metal organic acid salts of the series Zr ²⁺ , Zn ²⁺ , Fe ²⁺ , Fe ³⁺ , Ce ³⁺ , Cr ²⁺ , Cr ³⁺ and linear or cyclic organosiloxane oligomers with unsaturated groups on silicon atoms. The result of the reaction is siloxane oligomers or polymers containing a certain number of metal atoms. The patent descriptions indicate that the reaction mechanism is not installed, the reaction is not well understood, and the synthesized compounds have an indefinite structure. However, the obtained metallosiloxanes have several advantages, they are well compatible with various types of polymers, including various PICs, both liquid and solid, their molecular weight, regulated by the type of siloxane oligomer in the synthesis of metallosiloxane, is quite large.

Closest to the claimed functional polymetallosiloxanes are polymeric organosilicon compounds based on methylsilsesquioxane resin with metal atoms [(CH ₃ ) ₃ Si _0.5 ] [SiO ₂ ] (M), where M denotes a metal from the series Cr, Mo, W, Fe , Ni, Co, Mn, Re, Rh, Os, Ir (RF patent No. 1743173). Compounds are prepared by reacting methylsilsesquioxoxane resin with metal carbonyls. The yield of the target compounds is about 50%. The reaction is carried out in an environment of organic solvents at high temperatures. The resulting compounds are not considered as thermostabilizing additives, but only as catalysts for the conversion processes of organosilicon compounds.

Compounds closer in structure to the claimed functional polymetallosiloxanes are unknown.

The objective of the invention was to obtain a new technical result, which consists in creating new functional polymetallosiloxanes having the set of properties necessary for their effective use as thermostabilizing additives: contain in their structure a certain number of atoms of the corresponding metal, have good solubility in organic solvents and good compatibility with polymer matrix, contain functional groups capable of interacting action with the components of the polymer composition into which they will be introduced. In contrast to low molecular weight polymetallosiloxanes, they should have better compatibility with high molecular weight polymers, such as organosiloxane resins and rubbers.

The problem is solved in that new functional polymetallosiloxanes are created, characterized in that they have a statistical cyclolinear structure of the general formula (I):

where M means a divalent or trivalent metal from the series: Zr, Zn, Fe (II), Fe (III), Ce, Cu, Cr, Sm, Eu, and the value m corresponds to the valency of the metal;

Alk means a substituent of CH ₃ - or C ₂ H ₅ - ;.

R ′ is a substituent of CH ₃ - or C ₆ H ₅ - or NH ₂ (CH ₂ ) ₃ -;

R ″ means a substituent CH ₂ = CH—;

n is 0 or 1;

R '' 'means at least one link from a number of links:

OSiR'R " _n (OAlk) _2-n ; -OSiR'R" (OAlk) _1-n O _1/2 -; -OSiR'R " _n (O _1/2 -) _2-n ;

k is from 2 to 500;

And means at least one simple bond and / or Alk.

In particular, functional polymetallosiloxanes may have the general formula

where M is a divalent metal from the series Zr, Zn, Fe (II), Cu;

R ′, R ", A, n have the above meanings.

Moreover, in the case n is 1, they can be represented by the general formula

where R ′, R ", A, have the above meanings.

If n is 0, the general formula is as follows:

where R 'and A have the above meanings.

In particular, in the case of a trivalent metal, functional polymetallosiloxanes may have the general formula:

where M is a trivalent metal; R ′, R ", R '", A, n have the above meanings.

Moreover, in the case n is equal to 1, they can be represented by the general formula:

where R ′, R ", R" ', A have the above meanings,

or in the case n is 0 the general formula

where R ', R' ", A have the above meanings.

As in the case of a divalent metal, and in the case of a trivalent metal, Alk may mean CH ₃ - or C ₂ H ₅ -, R 'may mean CH ₃ - or C ₆ H ₅ - or NH ₂ (CH ₂ ) ₃ -. In particular, in cases where n is O, R "means a substituent CH ₂ = CH -.

In all cases, polymetallosiloxanes can have a molecular weight of from 500, which corresponds to k is 2, to 100,000, which corresponds to k is 500.

Functional polymetallosiloxanes are obtained by hydrolytic polycondensation of functional metallosiloxanes of the general formula

where R ', R ", Alk, n, M, m have the above meanings, which in turn are obtained by the interaction of natrioxy (alkoxy) organosilane selected from the series natrioxy (alkoxy) organosilanes of the general formula (III),

where R ', R ", Alk, n have the above meanings, with a metal salt selected from a number of metal salts of the general formula (IV),

where m, M have the above meanings;

X is C1 or Br or CH ₃ COO-.

The ratio of metallosiloxane / water in moles is from 1 / 0.05 to 1/1 in the process of hydrolytic polycondensation. In addition, metallosiloxanes as starting reagents for polycondensation do not have to be isolated from the reaction mixture.

The process of obtaining the starting metallosiloxanes (in the case of their separation from the reaction mixture) can be represented as follows:

In particular, the interaction process is carried out at a stoichiometric ratio of the components in the environment of an organic solvent from a number of lower alcohols: methanol, ethanol, propanol and ethers: ether, THF, dioxane, dibutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, mainly at temperatures ranging from - 5 ° to 50 ° C.

The process of the interaction of sodium nioxy (alkoxy) organosilane of the general formula (III) with metal salts of the general formula (IV) can be carried out, in particular, simultaneously with the process of formation of the sodium nioxy (alkoxy) organosilane of the general formula (III) by the interaction of sodium hydroxide with the alkoxyorganosilane of the general formula (V) :

where R ', R ", Alk, n have the above meanings. In this case, the process is carried out without isolation of the sodiumoxy (alkoxy) organosilane, and the metallosiloxane is obtained in one step according to the following general scheme:

The general scheme of the process for producing functional polymetallosiloxanes by hydrolytic polycondensation of the starting metallosiloxanes can be represented as follows:

The degree of polycondensation of metallosiloxane is determined by the amount of water introduced into the reaction - the molecular weight of polymetallosiloxane increases with decreasing amount of water. Thus, it is possible to obtain both low molecular weight and high molecular weight functional polymetallosiloxanes.

In particular, when M is Cu ^{+ 2} , R 'is CH ₃ -, n is 0, A means a simple bond and / or CH ₃ -, the resulting polymetallosiloxane is a statistical cyclolinear polymer of the form:

In the case of M, it is Fe ⁺³ , when R 'is CH ₃ -, Alk is C ₂ H ₅ -, n is 0, the final product is a statistical cyclolinear structure:

In the case of M, it is equal to Zr ⁺² , when R 'is equal to CH ₃ -, R "is CH ₂ = CH-; Alk is C ₂ H ₅ -, n is 1, the final product is the following structure:

In contrast to the known polymetallosiloxane, the claimed functional polymetallosiloxanes contain various organic substituents, including functional ones, on silicon atoms, as well as metals of different valencies. This makes it possible to significantly improve the compatibility of such compounds and polymer compositions of various types, including varnishes and liquids, to obtain various modifications of these compounds using functional groups, and also by varying the type of metal to improve their heat-stabilizing effect when introduced into the polymer.

The structure of the synthesized compounds was proved by elemental analysis, NMR and IR spectroscopy, and chromatographic analysis methods.

According to GPC, both the starting oligomer and the products of its polycondensation at k from 2 to 500 have a unimodal molecular weight distribution (see Figure 1 and Figure 2). According to GPC data obtained using linear polystyrene standards, the molecular weights of metallosiloxanes correspond to ~ 200 (Figure 1). A more accurate definition of MM is not possible due to the lack of appropriate standards for a branched structure. Figure 2 shows as an example the GPC curve of the polymer iron-containing ethoxy-functional metallosiloxane, with M _p ~ 100000.

The claimed compounds have a structure that is optimal for incorporation into siloxane polymer compositions due to their polymer nature and the presence of functional groups, the use of which allows polymer-like transformations to further improve compatibility with certain polymer compositions, in contrast to known compounds, or monomeric, poorly compatible with polymers, or expensive polymer and not having functional groups. The presence of chemically bonded transition metal atoms in their structure allows the use of these compounds as effective thermostabilizing additives. The thermal stability of the functional metallosiloxanes themselves was rated as high based on data from studies of their thermal degradation (see figure 3). Figure 3 shows the TGA curves of the iron-vinyl siloxane oligomer in air and in an inert medium. As follows from the above results, their thermo- and thermo-oxidative degradation is not accompanied by the destruction of the molecular skeleton and the formation of fragments. Mass losses begin rather early (due to the high concentration of end groups) - the total losses in argon are less than 10%, and in air about 25%, which is significantly less than the real organic component of metallosiloxane.

The study of thermal stabilization of the polymer in the presence of synthesized metallosiloxane additives was carried out by the DTA method (the procedure is given in the examples). Methylsilsesquioxane resin was used as the polymer of the thermally stabilized polymer. The introduction of metallosiloxane additives in the composition of the resin was carried out by co-dissolution. The obtained results of the DTA tests, shown in the table, show that the activity of the obtained additives as heat stabilizers is high. As a comparative example, the table shows the parameters for silsesquioxane resin without the addition of metallosiloxanes.

In all cases, the amount of added additive was 2-3% calculated on pure metal. As can be seen from the data presented, in all cases, the stabilization effect is observed, so that the temperature of 10% loss with the introduction of methylethoxyzhelezosiloxane shifts by 90 ° C, and in the case of aminopropylethoxyceryl siloxane - by more than 120 ° C towards high temperatures. The coke residue content does not change, however, the maximum position on the DTA curve shifts in the case of the first additive by almost 180 ° C, and in the case of a cerium-containing modifier, by 140 ° C. Aminopropylethoxyzhelezosiloxane turned out to be less effective, but even in this case the properties of the composition are higher than in the comparative system.

Figure 1 presents the GPC curve of iron-containing methyldiethoxysiloxane.

Figure 2 presents the GPC curve of the product of hydrolytic polycondensation of iron-containing methyldiethoxysiloxane.

Figure 3 presents the TGA curves of iron-methylvinyl ethoxysiloxane;

curve 1 - heating in an argon medium, 2 - heating in air (heating rate of 5 ° C / min).

The table shows the DTA data of methylsilsesquioxane resin in the presence of metallosiloxanes as thermostabilizing additives according to examples 5 and 8. As a comparative example, the DTA data of pure methylsilsesquioxane resin are given. The invention can be illustrated by the following examples:

Synthesis of functional polymetallosiloxanes

Example 1. Synthesis of poly (copper) methylvinylsiloxane:

11.9 g (0.04 mol) of copper-containing methoxyfunctional methylvinylsiloxane Cu [OSiMeVinOMe] _{2 is} dissolved in 100 ml of THF and 0.08 ml (0.004 mol) of water is added with stirring in a ratio of 1 mol of metallosiloxane / 0.05 mol of H ₂ O. After 10 hours of stirring at room temperature, the volatiles were removed in vacuo. Product yield 73%. GPC: wide monomodal distribution M _p ~ 100000 (by polystyrene standards). NMR - ¹ H spectrum in CDCl ₃ : δ = 0.15 ppm. (p. 3H); δ = 1.2 ppm (m. 9H); δ = 3.71 ppm (m. 3H); δ = 5.92 ppm (m. 3H).

Example 2. Synthesis of poly (iron) methylsiloxane:

The synthesis is carried out according to the procedure described in example 1, but instead of Cu [OSiMeVinOMe] ₂ take Fe [OSiMe (OEt) ₂ ] ₃ . Product yield 73%. GPC: wide monomodal distribution M _p ~ 500 (by polystyrene standards). NMR - ¹ H spectrum in CDCl ₃ : δ = 0.15 ppm. (p. 3H); δ = 1.2 ppm (m. 9H); δ = 3.71 ppm (m. 3H); δ = 5.92 ppm (m. 3H).

Example 3. Synthesis of poly (cerium) methylvinylsiloxane:

The synthesis is carried out according to the procedure described in example 1, but instead of Cu [OSiMeVinOMe] _2, Ce [OSiMeVinOEt] _{3 is} taken, and the amount of added water is calculated from the ratio of 1 mol of metallosiloxane / 1 mol of H ₂ O. Product yield 73%. GPC: wide monomodal distribution M _p ~ 500 (by polystyrene standards). NMR - ¹ H spectrum in CDCl ₃ : δ = 0.15 ppm. (s.3H); δ = 1.2 ppm (m.); δ = 3.71 ppm (m.); δ = 5.92 ppm (m. 3H). According to infrared spectroscopy: band-Si-O-Si- - 1100 cm ^-1 ; band —Ce-O-Si- —790 cm ⁻¹ .

Example 4. Synthesis of poly (zirconium) methylsiloxane:

0.0274 mol of zirconium chloride, 0.0822 mol of methyltriethoxysilane and 3.29 g (0.0822 mol) of sodium hydroxide are mixed in 200 ml of THF, at a temperature of 0 ° C, in an inert gas medium. The reaction mixture was stirred for 4 hours at room temperature. 0.0274 mol of water is added to the reaction mixture with stirring, in a ratio of 1 mol of metallosiloxane / 1 mol of H ₂ O. After 10 hours of stirring at room temperature, volatile components are removed in vacuo. Product yield 73%. GPC: wide monomodal distribution M _p ~ 500 (by polystyrene standards). NMR - ¹ H spectrum in CDCl ₃ : δ = 0.15 ppm. (s.3H); δ = 1.2 ppm (m.); δ = 3.71 ppm (m.); δ = 5.92 ppm (m. 3H).

Synthesis of starting oligomers:

Example 5. Synthesis of iron-containing ethoxy-functional methylsiloxane.

To 4.45 g (0.0274 mol) of iron (III) chloride in 200 ml of THF, a solution (0.0822 mol) of sodium oxymethyldiethoxysilane in 70 ml of THF was added dropwise at a temperature of + 5 ° C. The reaction mixture was stirred at 50 ° C for 28 hours. The precipitate of sodium chloride is filtered off, the volatiles are removed in vacuo. Product yield 68%. According to the elemental analysis found: Fe 9.39%; Si 17.41%; C 36.28%; H, 8.02%. Calculated: Fe 11.09%; Si 16.74%; C 35.8%; H 7.75%.

Example 6. The synthesis of samarium-containing ethoxyfunctional methylsiloxane.

7.036 g (0.0274 mol) of samarium chloride, 14.64 g (0.0822 mol) of methyltriethoxysilane and 3.29 g (0.0822 mol) of sodium hydroxide are mixed in 200 ml of THF, at a temperature of 0 ° C, in an inert medium gas. The reaction mixture was stirred for 4 hours at room temperature. The precipitate of sodium chloride is filtered off, ethanol and excess methyltriethoxysilane are removed in an oil pump vacuum. Product yield 79%. GPC: monomodal distribution of M _p = 200 according to polystyrene standards. According to elemental analysis, found: Sm 24.52%; Si 14.46%; C 43.03%; H 6.99%. Calculated: Sm 25.11%; Si 14.06%; C 42.19%; H 6.53%.

Example 7. Synthesis of copper-containing ethoxy-functional methylvinylsiloxane.

The synthesis is carried out according to the method described in example 6, but instead of samarium chloride, copper chloride is used, instead of methyltriethoxysilane, methylvinyl diethoxysilane is used, all in an equimolar amount. The yield of 82.2%. GPC: monomodal distribution M _p = 200 (by polystyrene standards). NMR ¹ H spectrum in CDCl ₃ : δ = 0.15 ppm. (s.9H); δ = 1.2 ppm (m. 9H); δ = 3.71 ppm (m. 6H); δ = 5.92 ppm (m. 9H). Elemental analysis: found%: Si 22.68; Cu 13.39; C 29.76; H, 5.71. Calculated%: Si 18.75; Cu 12.46; C 40.06; H, 7.35.

Example 8. The synthesis of cerium-containing ethoxyfunctional methylvinylsiloxane:

The synthesis is carried out according to the method described in example 7, but instead of copper chloride, cerium chloride is used in an equimolar amount. The product yield of 79.2%. GPC: monomodal distribution M _p = 200 (by polystyrene standards). NMR - ¹ H spectrum in CDCl ₃ : δ = 0.15 ppm. (s. 9H); δ = 1.2 ppm (m. 9H); 5 = 3.71 ppm (m. 6H); 5 = 5.92 ppm (m. 9H).

Example 9. Synthesis of zirconium-containing methoxy-functional siloxane:

The synthesis is carried out according to the method described in example 6, but instead of iron chloride, zirconium chloride is used in an equimolar amount. The product yield of 89.5%. GPC: monomodal distribution M _p = 200 (by polystyrene standards). NMR - ¹ H spectrum in CDCl ₃ : δ = 0.15 ppm. (s. 9H); δ = 1.2 ppm (m. 9H); δ = 3.71 ppm (m. 6H); δ = 5.92 ppm (m. 9H). Elemental analysis: Found%: Si 17.66; Zr 27.79; C 14.66; H, 5.71. Calculated%: Si 17.20; Zr 28.04; C 14.76; H 5.5.

Test procedure for the thermostabilizing action of metallosiloxanes.

A solution of 0.7 g of methylsilsesquioxoxane resin in 6.5 ml of methyl tert-butyl ether (MTBE) and a solution of 0.14 g of tris (diethoxymethylsiloxy) iron (or other synthesized metallosiloxane) in 2 ml of MTBE (1.8% Fe by weight of resin) are mixed. The resulting homogeneous solution is kept in air in a thin layer until the solvent dries. The obtained uniform transparent film is heated in a vacuum oven at a temperature of 200 ° C for 2 hours. Analyze the obtained sample by DTA and compare with the DTA data of methylsilsesquioxane resin without the addition of metallosiloxanes. The results of a number of tests are shown in the table.

Table Example No. Type of additive metallosiloxane T _10% , ° C % coke The maximum position on the DTA curve, ° C 5 Fe [OSi CH ₃ (OC2H5) ₂ ] ₃ 620 88 620 8 Ce [OSiCH ₃ (OS ₂ H ₅ ) ₂ ] ₃ 650 89 567 Comparative analysis no 533 88 437

Claims (24)

1. Functional polymetallosiloxanes, characterized in that they have a statistical cyclolinear structure of the general formula (I)

where M means a divalent or trivalent metal from the series: Zr, Zn, Fe (II), Fe (III), Ce, Cu, Cr; Sm; Eu, and the value of m corresponds to the valency of the metal; Alk is a substituent of CH ₃ - or C ₂ H ₅ -; R 'is a substituent of CH ₃ - or C ₆ H ₅ - or NH ₂ (CH ₂ ) ₃ -; R "means a substituent CH ₂ = CH-; n is 0 or 1; R '"means at least one link from a number of links: -OSiR'R" _n (OAlk) _2-n ; -OSiR'R '(OAlk) _1-n O _1/2 ; -OSiR'R '' _n (O _1/2 -) _2-n ; k takes values from 2 to 500; And means at least one simple bond and / or Alk. 2. Functional polymetallosiloxanes according to claim 1, characterized by the general formula

where M is a divalent metal from the series Zr, Zn, Fe (II), Cu; R, R "k, A, n have the above meanings. 3. Functional polymetallosiloxanes according to claim 2, characterized by the general formula

where n is 1, R, R ", k, A have the above meanings. 4. Functional polymetallosiloxanes according to claim 2, characterized by the general formula

where n is O, R ', k, A have the above meanings. 5. Functional polymetallosiloxanes according to claim 1, characterized by the general formula

where M is a trivalent metal from the series Fe (III), Ce, Cr, Sm, Eu; R, R ", R '", k, A, n have the above meanings. 6. Functional polymetallosiloxanes according to claim 5, characterized by the general formula

where n is 1, R, R ", R '", k, A have the above meanings. 7. Functional polymetallosiloxanes according to claim 5, characterized by the general formula

where n is O, R ', R' ", k, A have the above meanings. 8. Functional polymetallosiloxanes according to claim 2 or 5, characterized in that Alk means CH ₃ -. 9. Functional polymetallosiloxanes according to claim 2 or 5, characterized in that Alk means C ₂ H ₃ -. 10. Functional polymetallosiloxanes according to claim 2 or 5, characterized in that R 'means CH ₃ -. 11. Functional polymetallosiloxanes according to claim 2 or 5, characterized in that R 'means C ₆ H ₅ -. 12. Functional polymetallosiloxanes according to claim 2 or 5, characterized in that R 'is NH ₂ (CH ₂ ) ₃ -. 13. Functional polymetallosiloxanes according to claim 3 or 6, characterized in that R "means a substituent CH ₂ = CH-. 14. Functional polymetallosiloxanes according to any one of claims 1 to 7, characterized in that k is 2. 15. Functional polymetallosiloxanes according to any one of claims 1 to 7, characterized in that k is 500. 16. Functional polymetallosiloxanes according to any one of claims 1 to 7, characterized in that they are obtained by hydrolytic polycondensation of a functional metallosilox selected from a number of functional metallosiloxanes of the general formula (II),

where M, m, R ′ R, Alk, n have the above meanings, and the ratio of metallosiloxane / water in moles is from 1 / 0.05 to 1/1. 17. Functional polymetallosiloxanes according to clause 16, characterized in that the functional metallosiloxanes of the general formula (II) are first prepared by reacting natrioxy (alkoxy) organosilane selected from the series of natrioxy (alkoxy) organosilanes of the general formula (III)

where R ', R ", Alk, n have the above meanings, with a metal salt selected from a number of metal salts of the general formula (IV),

where M, m have the above meanings, X is Cl or Br or CH ₃ COO-, after which the obtained functional metallosiloxane selected from a number of functional metallosiloxanes of the general formula (II) is subjected to hydrolytic polycondensation. 18. Functional polymetallosiloxanes according to claim 17, characterized in that the ratio of metallosiloxane / water in moles is 1 / 0.05. 19. Functional polymetallosiloxanes according to claim 18, characterized in that the copper-containing methoxy-functional methylvinylsiloxane is used as the metallosiloxane. 20. Functional polymetallosiloxanes according to claim 18, characterized in that iron (III) containing ethoxy functional methylsiloxane is used as metallosiloxane. 21. Functional polymetallosiloxanes according to claim 17, characterized in that the ratio of metallosiloxane / water in moles is 1/1. 22. Functional polymetallosiloxanes according to item 21, characterized in that cerium-containing ethoxy-functional methylvinylsiloxane is used as metallosiloxane. 23. The functional polymetallosiloxanes according to claim 21, characterized in that zirconium-containing ethoxy-functional methylsiloxane is used as metallosiloxane. 24. Polymetallic siloxanes according to any one of claims 1 to 7, and 17-23, characterized in that they are intended for use as a thermostabilizing additive in polymer compositions.

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