RU2470958C1 - Method of producing elastomeric metal-containing composite materials - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: metal-containing compounds are entered into a polymer matrix and the metal-containing compounds in the polymer undergo high-speed thermal decomposition while stirring continuously. The polymer used is carbon-chain rubber. The metal-containing compounds are selected from variable valence metal formates.

EFFECT: invention simplifies the technique of producing said materials, high efficiency and obtaining elastomeric articles based on carbon-chain rubber.

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Description

The invention relates to nanotechnology for producing elastomeric composite materials modified with metals of variable valency, to increase their thermal conductivity, electrical conductivity, heat resistance under high temperature operating conditions and to give elastomers other specific and unique physical and operational properties.

A known technique for filling polymers with metals by mechanical mixing of metal powders and polymer binders in certain weight proportions with thorough mixing and subsequent processing (Fillers for polymer composite materials: reference manual / Edited by G.S. Katz, D.V. Milevsky - M .: Chemistry, 1981. - 575 p.).

The disadvantage of this method is the difficulty of using metal powders with a high degree of dispersion, while highly dispersed metal powders are rapidly oxidized in air, which reduces their useful characteristics and limits the storage time and temperature conditions of processing. In addition, when using this method, there is a deterioration in the properties of polymer composites after high-temperature aging and a decrease in the temperature at which the destruction of materials begins.

Also known is a method of producing metal polymers by the method of thermal reduction of metal formates in polymer melts (Natanson E.M., Ulberg Z.R. Colloidal metals and metal polymers - Kiev: Naukova Dumka, 1971. - 348 S.).

The disadvantage of this method is that elastomers in a highly elastic state are more viscous than melts of thermoplastics or thermosets, and the pour point of elastomers is usually above the temperature of destruction, which makes it difficult to obtain melts from elastomers.

A known method of producing magnetic polymer compositions on nanoscale ferrite particles for radio engineering products (Pat. 2315382 RF, IPC H01F 10/00, H01F 1/113 - 01/20/2008), including high-speed thermal decomposition of metal-containing compounds in a thermoplastic polymer melt when exposed to high-voltage short-pulse electric discharge voltage of 15-20 kV, duration 1-10 ms.

The disadvantage of this method is the high complexity, low product yield and the inability to wash the elastomer from mineral oil.

The closest in technical essence and the problem to be solved is a method for producing elastomeric metal-containing composite materials (Pat. 2412957 RF, IPC C08K 5/098, C08L 9/00 - 02/27/2011), including high-speed thermal decomposition of metal-containing compounds selected from acetates and metal formates of variable valencies in the polymer.

An ethylene propylene copolymer is selected as the polymer. The metal-containing compound is introduced into the polymer matrix before the decomposition process, carried out in a metal form, restricting the access of atmospheric oxygen, the degree of filling of which is 80-90%. The elastomeric composition is heated in a form restricting air access at a decomposition temperature of the precursor for 60 minutes.

The disadvantages of the proposed invention are the low yield, poor dispersion of the resulting metal particles in the elastomer and the inability to obtain elastomeric metal-containing composite materials based on unsaturated rubbers.

Thus, the known method does not allow to obtain elastomeric metal-containing composite materials based on unsaturated rubbers.

The reason that impedes the achievement of the required technical result when using the known method for producing elastomeric composite materials modified with metal particles is the need for long exposure of elastomers at a high temperature corresponding to the synthesis temperature of metal particles and close to the temperature of destruction of unsaturated rubbers. At the same time, during the time required for high-temperature synthesis of metal particles, partial destruction of the elastomeric matrix of unsaturated rubber occurs, which reduces the consumer and operational qualities of the metal-containing elastomeric composite.

The objective of the present invention is to develop a new method for producing elastomeric compositions modified by metal particles, which would allow to intensify the process of obtaining elastomeric metal-containing composite materials and to simplify the production cycle of the manufacture of heat-resistant elastomeric products based on them for high-temperature operating conditions.

The technical result of the proposed method is to simplify the production technology, increase productivity and obtain heat-resistant elastomeric products based on carbochain rubbers.

The technical result is achieved by the fact that in the method for producing elastomeric metal-containing composite materials, which includes introducing metal-containing compounds selected from metal formates of variable valency into a polymer matrix and subsequent high-speed thermal decomposition of metal-containing compounds in a polymer, carboxylic rubber is used as the polymer, and the metal-containing decomposition process compounds in carbochain rubber are carried out with continuous stirring, providing high sd igovye rubber deformation.

A binary mixture of carbochain rubber with a precursor is prepared on standard mixing equipment of the rubber industry (on rollers or in a rubber mixer), and then the elastomeric composition is heated in a rubber mixer with a rotor speed of the high-speed rotor of at least 40 rpm.

The essence of the invention lies in the fact that when heated, the precursor decomposes with the release of metal, the particles of which are stabilized by an elastomeric matrix:

Me (HCOO) ₂ = Me ↓ + 2CO ₂ ↑ + H ₂ ↑,

where Me is a metal of variable valency.

High shear deformations of rubber, which arise as a result of mixing of the reaction medium during the entire process of decomposition of the precursor, contribute to better dispersion of metal particles in the elastomeric composite material.

The stabilizing effect of ultrafine particles of metals of variable valency is explained by the following factors. The high-temperature thermo-oxidative degradation of polyolefins is caused, on the one hand, by the breaking of chemical bonds and the formation of R · macroradicals, and, on the other hand, by the formation of RO ₂ · radicals as decomposition products of hydroperoxides resulting from the oxidation of polymer macromolecules.

The high activity of ultrafine metal particles with respect to oxygen allows one to inhibit the formation of hydroperoxides and their decomposition products. In fact, colloidal particles of metals of variable valency act as an oxygen acceptor.

In addition, ultrafine metal particles can be active radical scavengers that inhibit thermal degradation. Well-known reactions of metals of variable valency with alkyl radicals leading to the formation of organometallic compounds, for example:

Me + 4R → MeR ₄

Thus, metal particles, entering into chemical interaction with alkyl radicals, inhibit the processes of thermal degradation and form secondary network structures, which leads to increased heat resistance of the elastomeric composite.

In the proposed method, the following components are used.

Copper formate dihydrate Cu (HCOO) ₂ · 2H ₂ O (TU 6-09-4384-77), nickel formate dihydrate Ni (HCOO) ₂ · 2H ₂ O (TU 6-09-02-478-88) are used as a precursor ) Other types of precursors may be used.

SKEPT-40 ethylene-propylene rubber (TU 2294-022-05766801-2002), SKI-3 isoprene rubber (GOST 14925-79), SKD-II butadiene rubber (GOST 14924-75), and butadiene-nitrile are used as carbochain rubbers SKN-18SM rubber (TU 38.40375-2001), styrene butadiene rubber SKMS-30ARK (GOST 15627-79), butyl rubber BK-1675N (TU 2294-017-48158319-2000).

The method of obtaining elastomeric copper-containing composite materials is as follows.

On a laboratory roll, for example, LB 450 225/225, a binary mixture of carbon chain rubber with a precursor is prepared.

The resulting polymer mixture with a precursor is placed in a rubber mixer, for example, a Brabender 0.1 micromixer. The decomposition of the precursor is carried out at a rotational speed of the high-speed rotor of 65 rpm.

Then, the resulting composite is extracted from the rubber mixer and can be further processed and studied.

The composition of the modified samples is determined on a DRON-3.0 general-purpose x-ray diffractometer in Cu _Kα radiation (Ni filter). When the speed of the counter is 2 deg / min - mark the corners after 1 degree. Phase identification is based on interplanar spacing data calculated using the Wulf-Bragg equation using the ASTM file cabinet.

The temperature of 5% (t ₅ ) and 10% (t ₁₀ ) of the mass loss of the studied composites is determined on a Paulik-Paulik-Erdey derivatograph of the MOM company (Hungary) in an air atmosphere in the temperature range of 20-600 ° C at a heating rate of 12 ° / min

The following examples illustrate but do not limit the essence of the invention.

Example 1

A binary mixture of 100 g of ethylene-propylene rubber with 29.8 g of copper formate Cu (HCOO) ₂ · 2H ₂ O was prepared on laboratory rollers.

The resulting mixture of carbochain rubber with a precursor was placed in a rubber mixer and heated with continuous stirring of the rubber with the precursor at a temperature of 190 ° C for 10 minutes. The temperature was maintained with an accuracy of ± 1 °.

Synthesis in a polymer matrix proceeds mainly by the reactions:

Cu (HCOO) ₂ · 2H ₂ O = Cu (HCOO) ₂ + 2H ₂ O ↑;

Cu (HCOO) ₂ = Cu ↓ + 2CO ₂ ↑ + H ₂ ↑.

The phase composition of the obtained binary composite material was studied by X-ray diffraction analysis on a DRON-3.0 apparatus, according to the results of which reflections from the planes of the metal crystal lattice are observed in the composite, the distances between which are d _hkl = 2.08; 1,798; 1.27; 1,083 and 1,038 Å, which corresponds to the ASTM card index series d _{hkl of} copper (figure 1).

The heat resistance of the obtained elastomeric copper-containing composite material is shown in table 1.

Example 2

Binary mixtures were prepared according to example 1, changing the temperature and duration of decomposition of the precursor.

The phase composition of the obtained elastomeric composite materials was studied by X-ray diffraction analysis on a DRON-3.0 apparatus (figure 1). According to the results of X-ray diffraction analysis, it is seen that at T <190 ° C, reflections from the planes of the crystal lattice are observed in the composites, which do not correspond to reflections characteristic of copper.

Example 3

Binary mixtures were prepared according to example 1, changing the rubber. Isoprene rubber, butadiene rubber, styrene butadiene rubber, butyl rubber, nitrile butadiene rubber were used as carbochain rubber.

The phase composition of the obtained binary composite materials was studied by X-ray diffraction analysis on a DRON-3.0 apparatus, according to the results of which reflections from the planes of the metal crystal lattice are observed in the composites, corresponding to the d _hkl series of copper according to the ASTM card file (figure 2).

The heat resistance of the obtained elastomeric copper-containing composite materials is shown in table 1.

Example 4

A binary mixture of 100 g of carbochain rubber with 31.5 g of nickel formate Ni (HCOO) ₂ · 2H ₂ O was prepared on laboratory rollers. Ethylene-propylene rubber, butadiene rubber, styrene butadiene rubber, butyl rubber, butadiene nitrile were used as carbochain rubber rubber.

The resulting mixture of carbochain rubber with a precursor was placed in a rubber mixer and heated with continuous stirring of the rubber with the precursor at a temperature of 220 ° C for 10 minutes. The temperature was maintained with an accuracy of ± 1 °.

Synthesis in a polymer matrix proceeds mainly by the reactions:

Ni (HCOO) ₂ · 2H ₂ O = Ni (HCOO) ₂ + 2H ₂ O ↑;

Ni (HCOO) ₂ = Ni ↓ + 2CO ₂ ↑ + H ₂ ↑;

Ni (HCOO) ₂ = Ni ↓ + CO ₂ ↑ + H ₂ O ↑ + CO ↑.

The phase composition of the obtained binary composite materials was studied by X-ray diffraction analysis on a DRON-3.0 apparatus, according to the results of which reflections from the planes of the metal crystal lattice are observed in the composite, the distances between which are d _hkl = 2.03; 1.76; 1.24 and 1.06 Å, which corresponds to the ASTM card index series d _hkl Nickel (figure 3).

The heat resistance of the obtained elastomeric metal-containing composite materials is given in table 1.

From the data presented in figure 1-3, it can be seen that the inventive method allows to obtain elastomeric metal-containing composite materials based on carbon chain rubbers.

From the data of table 1 it is seen that the temperature of a 5% weight loss by 10-35 ° and the temperature of a 10% weight loss by 5-20 ° increase in carbochain rubbers modified with metals of variable valency, which indicates an increase in the heat resistance of the obtained elastomeric metal-containing composite materials.

In addition, the use of the proposed method can significantly reduce the total time for producing elastomeric metal-containing composite materials (since the time of synthesis of free metal particles in an elastomeric matrix is reduced several times) and energy costs (since the proposed method allows to reduce the synthesis temperature by several tens of degrees), which leads to an increase in the yield of the finished product.

Table 1. Temperature of 5% (t ₅ ) and 10% (t ₁₀ ) mass loss of the studied composites Type of elastomeric material t ₅ , ° C t ₁₀ , ° C SKEPT-40 340 360 SKEPT-40 + Cu (10%) 370 385 SKEPT-40 + Ni (10%) 365 380 SKI-3 360 375 SKI-3 + Cu (10%) 375 385 SKD 360 380 SKD + Cu (10%) 370 390 SKD + Ni (10%) 370 385 SKN-18 400 425 SKN-18 + Cu (10%) 420 435 SKN-18 + Ni (10%) 415 430 SKMS-30 375 400 SKMS-30 + Cu (10%) 390 415 SKMS-30 + Ni (10%) 385 410 BK-1675 375 420 BK-1675 + Cu (10%) 410 445 BK-1675 + Ni (10%) 395 435

Thus, the above information indicates the fulfillment of the following set of conditions when using the claimed invention:

the method embodying the claimed invention in its implementation, allows to obtain elastomeric metal-containing composite materials to increase the heat resistance of polymer products under high temperature operating conditions;

The claimed invention allows to obtain elastomeric metal-containing composite materials for the development of heat-resistant rubber;

for the claimed invention, in the form described in the independent clause of the claims below, the possibility of its implementation using the means and methods described above or known prior to the priority date is confirmed;

means that embody the claimed invention in its implementation, is able to ensure the achievement of the perceived by the applicant technical result.

Therefore, the claimed invention meets the requirement of "industrial applicability" under applicable law.

Claims (2)

1. A method of producing elastomeric metal-containing composite materials, including the introduction of metal-containing compounds selected from formates of metals of variable valency into the polymer matrix and subsequent high-speed thermal decomposition of metal-containing compounds in the polymer, characterized in that the polymer used is carbon chain rubber, and the decomposition process of the metal-containing compound in carbochain rubber is carried out with continuous stirring, providing high shear deformations of kau UCA. 2. The method according to claim 1, characterized in that rubbers selected from the group are used as carbochain rubber: isoprene rubber, butadiene rubber, styrene butadiene rubber, butyl rubber, ethylene-propylene rubber, nitrile butadiene rubber.

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