EA007560B1 - Polyamide nanomaterial - Google Patents

Abstract

The invention relates to polymer materials science and can be used when developing composite materials of tribotechnical and structural use based on aliphatic polyamides.It is known the use of nanodispersed clayey materials for filling thermoplastic polymers, including aliphatic polyamides. But the level of tribotechnical and mechanical properties of aliphatic polyamides, filled with clayey minerals, is not high.The object of the present invention is to improve performance indices of tribotechnical properties of polyamide nanomaterials.According to the invention the problem is solved by using in the polyamide nanomaterial, which comprises aliphatic polyamide and modified addition, a mixture of initial and functionilized polyolefins with mass ratio from 1:13 to 15:1 and nanodispersed clayey mineral processed by products of refined oil purification. An additional improvement of operating properties of polyamide nanomaterial is achieved by introducing into it a fiberfill and (or) a mineral filler, as well as a stabilizer of thermal-acid destruction of polyamide and polyolefin.The proposed invention provides to improve indices of tribotechnical properties of nanomaterials based on aliphatic polyamide and is effective in using aliphatic polyamides, a mixture of olefin polymers and clayey minerals of different origin.

Description

The invention relates to polymer materials science and can be used to create composite materials for tribological and structural purposes based on aliphatic polyamides (PA).

It is widely known the use of dispersed clay materials for filling thermoplastic polymers, including aliphatic polyamides (Fillers for polymer composite materials (Reference manual) Translated from English, edited by G.S. Katz, D.V. Milevsky. M. Chemistry 1981, pp. 130-132, 152-159). However, the level of indicators of the tribological properties of aliphatic polyamides filled with clay minerals is not high enough.

The use of traditional antifriction (graphite, molybdenum disulfide, liquid and grease, etc.) and hardening additives (basalt or glass fiber, mica, glass beads, etc.) as fillers does not allow to achieve a combination of a high level of tribotechnical and physico-mechanical properties (Myshkin N.K., Petrokovets M.M. Tribology. Principles and applications. Gomel, 2002. S. 188-196).

It is known that the tribotechnical properties of PA can be improved by introducing other polymers, in particular polyethylene (Aderiha V.N., Dovgyalo V.A., Pleskachevsky Yu.M., Konopleva II. Effect of radiation-chemical modification polyethylene on the structure and tribological properties of polymer-polymer mixtures of polyamide-polyethylene. Friction and wear. 2000, T.2, No. 2. S. 167-173). However, the level of indicators of the mechanical properties of materials decreases in comparison with the initial PA, which negatively affects the load capacity of the parts.

The closest analogue (prototype) of the alleged invention is a nanomaterial, which is a composition of an aliphatic polyamide and a layered clay mineral, the surface of the particles of which is treated with octadecylamine (Li 1., Οί Ζ., Ιιιι ι. rgosekk. 1oitpa1 o £ Arrieb Ro1uteg 8s1epse. 1999. V. 71. P. 1133-1138, prototype). The use of nanodispersed clay filler as a reinforcing additive leads to the creation of polyamide compositions with improved mechanical characteristics. However, the material thus obtained has a relatively low level of indicators of tribological properties.

In addition, the well-known PA material containing a clay nanofiller has a high cost due to the high cost of ammonium surfactants and the complexity of the technology for treating the surface of clay mineral particles. This fact negatively affects the competitiveness of polyamide nanocomposites, for economic reasons.

The objective of the proposed invention is to improve the performance of the tribological properties of polyamide nanomaterial. The problem is solved in that in a polyamide nanomaterial including an aliphatic polyamide and a modifying additive, according to the invention, as a modifying additive, a mixture of the initial and functionalized, containing polar functional groups of polyolefins containing macromolecules in a mass ratio of from 1:13 to 15: 1 is used , and additionally nanodispersed clay mineral treated with refined products of vegetable oil in the following ratio of components (wt.%):

A mixture of polyolefins 1-30

Nanodispersed clay mineral 0.5-10

Aliphatic polyamide Else up to 100

An additional improvement in the set of indicators of the properties of the polyamide nanomaterial is achieved by the fact that it additionally contains fibrous aggregate in an amount of 2-20 wt.%, As well as powdered mineral filler in an amount of 1.5-15 wt.% And a thermal oxidative degradation stabilizer of aliphatic polyamide and polyolefin in an amount 0.2-0.5 wt.%.

The effectiveness of the proposed invention is confirmed by a series of comparative experiments shown in the table. In their implementation, the following materials are used. Aliphatic PAs: polyamide 6 (PA6), grade 210/310 manufactured by JSC GrodnoKhimvolokno (TU RB 00206262.151-97), polyamide 66 (PA66) manufactured by the Chernigov JSC Khimvolokno (OST 6-06-C23-84). Mixtures of polyolefins: mixtures of high density polyethylene (GOST 16338-85, grade 277) and functionalized HDPE containing polar groups in the composition of macromolecules (TU RB 03535279.027-97, grade PF-2). The HDPE / PF-2 mixtures in the ratios indicated in the table are obtained by coextrusion of the components at a temperature of 200 ° C (other polyolefin-based mixed systems were similarly prepared). To obtain the LDPE / PF-1 mixture, low-density polyethylene of the grade 15803-020 (GOST 1633677) and PF-1 (TU RB 03535270-015-97) are used; PP / PPF-1 - polypropylene grades 21030-16 (GOST 26996-86) and Sh1F-1 (TU RB 4000846.072-2003) (table). Clay minerals - bentonite powder (Sgabe B-160) manufactured by Epde1datb (USA), montmorillonite powder manufactured by B1ika (Switzerland) with an exchange cationic capacity of 100 mmol / 100 g. Octadecylamine (ODA, qualification “h”) manufactured by Megsk- 8cisbag! (Germany). Unrefined rapeseed and sunflower oil.

As fiber fillers, chopped glass fiber is used (EC grade 13-4.5-52C,

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TU RB 057 80349033-2002 produced by OJSC Fiberglass, Polotsk, Belarus) and low-modulus carbon fiber UIM (TU RB 400031289.127-2000, manufactured by OJSC Svetlogorskkhimvolokno, Belarus).

Mineral fillers are mica, grade SMF-100, GOST 855-74 and talc grade SMT№3U, TU 5727-001-40437333-00, manufactured by Amazolit CJSC, Russia).

As stabilizers of thermo-oxidative degradation, products are used, which are manufactured by C1Ba Ce1§u, Switzerland — irganox-1010 (pentaerytholtetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]) and a mixed stabilizer B-1171, which is a 1: 1 mixture (parts by weight) of a high molecular weight, nitrogen-containing sterically hindered phenolic antioxidant irganox 1098 (MI-hexane-1,6-diyl-bis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide ]) and thermostabilizer irgafos 168 (tri- (2,4-di-tert-butylphenol) phosphite).

The methods of preparation (preparation) of nanodispersed clay mineral powders, polyamide nanomaterials, as well as experimental samples and their properties are given in the description of the corresponding examples in the table.

Examples of polyamide nanocomposites and their properties

Components, performance indicators of compositions, units of measure The composition of the polyamide nanomaterial, the serial number of the experiment, the values of the properties Proto- type of Suggested Nanomaterial Outlawing compositions No. 1 Number 2 No. 3 Number 4 Number 5 Number 6 Number 7 Number 8 Number 9 Number 10 Number 11 Number 12 Number 13 Number 14 Number 15 Number 16 Number 17 Number 18 Number 19 Number 20 Number 21 Number 22 Number 23 Number 24 Number 25 Number 26 1. Components 1.1. Polyamide, wt. %: -PA6 -PA66 1.2. Modifying additive 1.2.1. Clay mineral, wt. %: - montmorillonite treated with ODA - PRTM treated montmorillonite - montmorillonite treated with PROPM - PRORM treated bentonite 1.2.2. A mixture of source and functionalized polyolefins, wt. % - HDPE / PF-2 (1:13) - HDPE / PF-2 (4: 1) - HDPE / PF-2 (15: 1) -PENP / PF-1 (4: 1) -PP / FPP-1 (4: 1) 97 5 97 5 98.5 0.5 one 80 5 fifteen 60 10 thirty 80 5 fifteen 80 5 fifteen 80 5 fifteen 80 5 fifteen 80 5 fifteen 80 5 fifteen 80 5 fifteen 86.5 0.5 one 70 5 fifteen 40 10 thirty 70 5 fifteen 97 0.5 one 73 5 fifteen 55 10 thirty 67 5 fifteen 79.8 5 fifteen 24.5 10 thirty 992 0.3 0.5 55 12 33 96.1 0.3 0.5 13,4 12 33

1.2.3. Fibrous filler, wt. %: - chopped CB - chopped hydrocarbon 1.2.4. Mineral filler, wt. % - mica -talc 1.2.5. The stabilizer of thermal oxidative degradation, wt. % - Irganox 1010 - Irganox B1171 2. Performance indicators 2.1. Yield strength in compression, MPa 83 96 95 84 75 95 86 85 87 82 80 88 2 105 10 110 twenty 107 10 112 1,5 105 7 115 fifteen 112 10 7 116 0.2 85 twenty fifteen 0.5 92 86 66 2 one oh 1 88 25 sixteen 0.6 68 2.2. Charpy impact strength, kJ / m ² 7 6 10 12 14 thirteen eleven 12 thirteen eleven 14 eleven eleven thirteen 12 14 10 12 eleven thirteen 12 eleven 7 nine 8 7 2.3. Coefficient of friction 0.44 0.42 0.4 022 020 023 022 022 025 021 026 027 0.33 027 024 024 035 026 025 026 024 0.19 0.42 0.19 0.34 023 2.4. Mass wear rate, • 10 ⁶ g / m 55 53 34 0.66 0.36 0.52 0.62 0.63 0.68 0.64 0.67 0.71 28 0.67 0.43 039 27 0.68 0.41 0.66 0.63 0.39 39 0.56 35 0.55

Examples 1, 2 characterize the properties of PA nanomaterials obtained according to the prototype. In this case, the surface of clay mineral particles used in the preparation of the compositions is modified as follows (I., ρΖ ΖΙ., ΖΙιιι X. Щ. , p. 1133-1138, prototype).

A clay mineral (montmorillonite or bentonite) in the amount of 80 g is dispersed in 5000 ml of hot water (80 ° C) with continuous stirring. ODA (31.1 g; 115 mmol) and concentrated hydrochloric acid (11.5 ml) were dissolved in 2000 ml of hot water (80 ° C). The resulting solution is mixed with a hot solution of montmorillonite in water and stirred vigorously for 5 minutes until a white precipitate is obtained. This precipitate is collected on a paper filter, it is washed three times with ~ 2500 ml of hot water (80 ° C) and dried by freezing in order to obtain a clay mineral with a surface of particles modified with ODA.

The pre-dried granules are treated with the obtained clay mineral powder

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PA6 and PA66 in the ratios given in the table. After that, the composition is extruded using a single-screw extruder (screw diameter 36 mm, b: 0 = 22) equipped with a special-purpose static mixer (Pc5c15ki 8.8. dGaGePd op BERE сп б б с б б то то то то то 11ep 51a1s. ί. LrrNsb Ro1ut. 8s1. 1997. ν. 65. Next, the extrudate in the form of strands is subjected to water cooling and granulation. The granulate obtained is dried to a residual moisture content of not more than 0.15% and processed by injection molding in order to obtain standard test specimens by compression method (cylindrical specimens with a diameter of 10 mm, height 15 mm, GOST 4551-82), and determine Charpy impact strength (bars 80x10x4 mm with a sharp notch, GOST 4647-80). The samples are cast on a DG3121-16P injection molding machine (injection volume 16 cm ³ ) according to the generally accepted and optimal modes for processing aliphatic polyamides (Kalinchev EL, Sakovtseva MB Properties and processing of thermoplastics. L. Chemistry. 1983). Tribotechnical testing of the sectors is carried out on a SMC-2 friction machine according to the scheme shaft - partial liner (sector). As a shaft using rollers made of steel 40X (NVS 50). The tests are carried out in sliding friction mode. At a speed of 0.63 m / s and a contact load of 1 MPa, the moment of friction is determined, and then the coefficient of friction is calculated by the formula:

£ = Μ / γ · Ν, here M is the moment of friction, Nm;

g is the radius of the roller, m;

N - load, MPa

The wear rate is determined by the formula

1 „= w / Y ·!, Here t is the loss of mass of the sample over time 1, g;

V is the sliding speed, m / s;

- test time (3600 s), s

Examples 3-12 characterize the compositions of materials and the properties of PA nanomaterials obtained in accordance with claim 1. At the same time, bentonite and montmorillonite treated with rapeseed oil (PRRM and sunflower oil (PRPM) refined products are used as clay minerals. Surface treatment of particles of clay minerals PRRM and PRPM is carried out as follows: in vegetable oil, previously heated to 90-95 ° С, clay mineral powder is added at the rate of 0.8 wt.% mineral when using rapeseed oil and 0.4 wt.% mineral when using sunflower oil.The mixture is continuously stirred for 35 minutes After which the suspension iltrated to separate clay mineral from clarified vegetable oil. The filtrate is used as a nano-filler for polyamide compositions. At the same time, it is applied to the surface of PA granules in a high-speed two-blade mixer at a temperature of polyamide granulate ~ 80 ° C. At the same time, other components of PA nanomaterials are introduced into the mixer. The technology for producing nanomaterials, experimental samples and their tests is similar to that described in examples No. 1-No. 2.

Examples 13-16 differ from examples 3-12 in that a fibrous filler is additionally introduced into the composition of the polyamide nanomaterial (claim 2). This operation is carried out at the stage of preparing a mechanical mixture of components and their subsequent coextrusion in a polyamide melt.

Examples 17-20 (claim 3 of the claims) differ from examples 13-16 in that instead of a fibrous filler, a powdered mineral filler or a mixture of chopped fibrous and powdered mineral fillers is used.

Examples 21-22 (claim 4 of the claims). Example 21 differs from examples 3-12 in that a thermal oxidative degradation stabilizer is additionally introduced into the composition of the polyamide nanomaterial.

Example 22 differs from example 21 in that, along with a stabilizer of thermal oxidative degradation, fibrous and powdery mineral fillers are additionally introduced into the composition of the polyamide nanomaterial.

Examples 23-26 (transcendental compositions).

Examples 23-24 differ from examples 3-5 in that the concentrations of the clay mineral and the mixture of polyolefins are outside the range of optimal component ratios.

Examples 25-26 differ from example 22 in that the concentrations of all additives included in the composition of the polyamide nanomaterial take a value lower (example 25) or higher (example 26), as specified in claims 1-4. Analysis of the experimental data presented in the table allows us to draw the following conclusions.

1. The use of the invention allows, in comparable experimental conditions, modeling the real conditions for compounding multicomponent polymer systems fairly well, to improve the set of indicators of the mechanical and tribotechnical properties of polyamide nanomaterials, while maintaining and slightly increasing the values of their mechanical properties: the friction coefficient decreases by 1.4- 2.3 times, the wear rate - 1.6-153 times, toughness increases by 40-50%.

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2. The invention is effective when using various types of aliphatic polyamides, layered nanodispersed clay minerals treated with refined products of various types of vegetable oils, as well as mixtures of different types of starting and functionalized polyolefins in the ratio specified in claim 1.

3. The introduction into the composition of polyamide nanomaterials fibrous or dispersed powdery fillers leads to an additional 6-42% increase in their compressive strength (claims 2, 3 of the claims).

4. The introduction of thermal oxidative degradation stabilizers into the composition of polyamide nanomaterials leads to an additional improvement in tribological performance.

The technical result of the proposed invention is as follows. Used in the case of the prototype polyamide nanomaterial, contains nanodispersed clay mineral that does not have antifriction properties. As a result of this, the tribotechnical parameters of the material are unsatisfactory and its use for the manufacture of parts intended for use in friction units is inappropriate. In the case of the present invention, the used (new) technology for preparing the surface of clay mineral particles leads not only to increase the mechanical properties of PA nanomaterials, but also helps to improve their tribological parameters in conjunction with additives of a mixture of the initial and functionalized polyolefins. The improved tribotechnical properties of the inventive polyamide nanocomposite are mainly explained by the presence in the clay mineral of fragments of fatty acids that are part of the products of refining vegetable oils (Tyutyunnikov VN Chemistry of fats. M., Food industry. 1968. S. 358-398) . In addition, liquid-acid fragments chemisorbed by the surface of clay minerals increase the adhesion strength of mineral particles with both a polyamide matrix and additives of polyolefin components. The latter circumstance is the obvious reason for the high level of indicators of the mechanical properties of materials.

The introduction of fibrous and (or) mineral fillers into the composition of the polyamide nanomaterial leads to an additional increase in the mechanical properties (especially compressive strength) for the following reasons: fillers contribute to a more uniform dispersion of clay mineral particles in the polymer matrix and limit the molecular mobility of the polymer components due to adsorption interaction .

The thermal oxidative degradation stabilizer (selected based on the need for simultaneous effective stabilization of the polyamide and polyolefin components that make up the nanomaterial) inhibits free macroradicals generated in the frictional interaction zone, thereby contributing to a decrease in the adhesion component of the friction force and increasing the resource of the metal-polymer friction pair.

Thus, the invention can be easily implemented, practically does not require additional capital costs and quite efficiently. It will be used in the production of polyamide nanomaterial for friction bearings, in particular, liners for ball joints of cars. The production of inserts will be organized at ZAO PO Track.

Claims (4)

CLAIM 1. Polyamide nanomaterial, including an aliphatic polyamide and a modifying additive, characterized in that as a modifying additive, a mixture of the initial and functionalized, containing polar functional groups of polyalephins containing macromolecules, is used in their mass ratio from 1:13 to 15: 1 and additionally nanodisperse clay mineral treated with refined products of vegetable oil in the following ratio of components, wt. %: A mixture of polyolefins 1-20 Nanodispersed clay mineral 0.5-10 Aliphatic polyamide Else up to 100 2. The polyamide nanomaterial according to claim 1, characterized in that it further comprises a fibrous filler in an amount of 2-30 wt.%. 3. The polyamide nanomaterial according to claim 1 or 2, characterized in that it further comprises a powdered mineral filler in an amount of 1.5-15 wt.%. 4. The polyamide nanomaterial according to any one of claims 1 to 3, characterized in that it further comprises a stabilizer of thermal oxidative degradation of aliphatic polyamide and polyolefin in an amount of 0.2-0.5 wt.%.