Method for assessing quality of mixing solutions of polymer composites

Abstract

FIELD: polymers.SUBSTANCE: invention relates to the field of quality control of the preparation of polymer composite solutions. The method for assessing the quality of mixing of polymer composite solutions includes measuring the estimated quality parameter and rejecting composite solutions with unsatisfactory mixing quality by comparing the value of the estimated quality parameter with the minimum rejection level. The evaluation parameter of the mixing quality is the specific electrical resistance.EFFECT: expansion of the functional capabilities of the method for monitoring the quality of mixing of polymer composite solutions.1 cl, 5 dwg, 3 tbl

Description

[0001] Field of technology to which the invention relates

[0002] The invention relates to the field of quality control of the preparation of polymer composite solutions after mixing the components.

[0003] Technology Level

[0004] A photometric method for assessing the quality of mixing a polymer composite solution by the uniformity of distribution of filler particles in the solution is known [1]. The method for assessing the quality of polymer composites includes: calibrating the device by measuring the intensity of the luminous flux I0 passed through the solution of unfilled polymer (“zero” solution); measuring the intensity of the luminous flux I t , passed through a polymer composite solution, previously subjected to mixing, and calculation of the transmittance coefficient of the polymer composite solution using the formula comparison of the average value of the transmittance of a polymer composite solution with a minimum level of culling and assessment of the quality of mixing (mixing is considered satisfactory when the condition is met ).

[0005] The specified method is implemented in assessing the quality of mixing aluminum nanoparticles in a solution of F-40S elastomer [1]. The manufacturer (Advanced Powder Technologies LLC) identifies the surface color of aluminum nanoparticles as gray [2], i.e. these are particles with a high light absorption coefficient α and, accordingly, a low reflectivity ρ ≤ 0.4 [3]. For gray bodies, the equality ρ + τ + α = 1 is valid [4]. If we take the color transmittance for aluminum particles τ = 0, the absorption coefficient of such particles is α≥0.6. When such particles are irradiated in a polymer solution, they, due to the high coefficient α, absorb most of the electromagnetic waves of light and, therefore, electromagnetic waves that have passed through the spaces between the particles in the polymer solution, as well as partially reflected from the filler particles, reach the photosensors of the light receiver. Due to the absorption of part of the light flux by particles, it is weakened. Calculation of the light transmittance coefficient Kt allows you to evaluate the uniformity of distribution of filler particles in the polymer solution and the quality of mixing.

[0006] The disadvantage of the method is its unsuitability for testing polymer solutions filled with white particles with a reflectance of ρ ≥ 0.6 [3]. The quality of mixing (uniform distribution) of aluminum oxide nanoparticles Al2O3 (α-phase) and aluminum nanoparticles Al in a solution of elastomer F-40S was assessed. The manufacturer (Advanced Powder Technologies LLC) identifies the surface color of aluminum oxide nanoparticles as white [2], i.e. these are particles with a high reflectance of ρ ≥ 0.6 and a low light absorption coefficient α ≤ 0.4. Comparative mixing of aluminum oxide and aluminum nanoparticles in a solution of elastomer F-40S was carried out manually and in an apparatus with a turbine stirrer for t = 1 min. During mechanized mixing, the stirrer rotation frequency was: for aluminum oxide nanoparticles n = 900 min -1, aluminum - n = 1300 min -1 .

[0007] The experimental results are presented in Table 1.

[0008]

[0009] It is obvious that the uniformity of nanoparticle distribution in the polymer solution will be higher after mechanical mixing than after manual mixing. Therefore, the transmittance of the luminous flux in the solution with aluminum nanoparticles after mechanical mixing is K. t =0.35, i.e. 1.6 times less than after manual mixing K t =0.56.

[0010] In a solution with aluminum oxide nanoparticles, the transmittance of the luminous flux has very high and almost identical values ​​after manual and mechanized mixing: K t =0.97u0.95.

[0011] Due to the high reflectivity ρ ≥ 0.6, white filler particles reflect most of the electromagnetic light waves back into the polymer solution, including in the direction of neighboring particles. The latter respond in kind, resulting in an overlap of electromagnetic waves, "illuminating" the entire volume of the solution. Therefore, the luminous flux reaching the photodetectors of the light receiver differs very little from the luminous flux intensity I t "zero solution" (3 and 5%), i.e. transmittance coefficient K t does not characterize or reliably reflect the uniformity of distribution of white particles in the volume of the solution.

[0012] Disclosure of invention

[0013] The objective of the claimed invention is to provide the ability to evaluate the quality of mixing in a polymer solution of filler particles of any color, including white particles with a high reflection coefficient ρ ≥ 0.6.

[0014] The technical result of implementing the invention will be the expansion of the functional capabilities of the method for assessing the quality of mixing of polymer composite solutions, namely: the ability to assess the quality of mixing of filler particles of any color in a polymer solution.

[0015] Description of the method

[0016] The claimed technical solution proposes evaluating the mixing quality of a polymer composite solution based on the uniformity of filler particle distribution within the solution. The mechanical properties of polymer composites are largely determined by the uniformity of filler particle distribution within the polymer matrix and the presence (or absence) of aggregation of these particles. The more uniform the filler particle distribution within the polymer matrix, the better the mechanical properties of the composite. Conversely, uneven particle distribution and the presence of aggregates of filler particles significantly impair the mechanical properties of the material.

[0017] Electrical resistance of the polymer solution composite ρ v also depends significantly on the distribution of particles in the solution.

[0018] The more uniformly the dielectric particles are distributed throughout the solution, the greater the electrical resistance of the composite solution. If the dielectric particles are unevenly distributed or aggregated, the current will flow between them through the polymer solution, which has lower electrical resistance (for dielectric particles). acetone SKN-40 rubber ). In this case, the electrical resistance of the composite solution will be less than with uniform distribution.

[0019] When filled with electrically conductive particles, the opposite occurs. The electrical resistance of the filler particles, which conduct electrical current, is lower than the resistance of the polymer solution. The more uniformly the electrically conductive particles are distributed throughout the solution, the more conductive bridges there are and the lower the resistance of the composite solution. If the conductive particles are unevenly distributed or aggregated, the polymer solution, which has a higher resistance, is located between them, so the resistance of the composite solution will be higher than with a uniform distribution.

[0020] The method for assessing the quality of mixing of polymer composite solutions includes:

[0021] 1. Measurement of electrical resistance R of a pre-stirred polymer composite solution and calculation of the specific volume electrical resistance of a particle-filled polymer composite solution

[0022] 2. Comparison of the average value of specific electrical resistance of the polymer composite solution with a minimum level of culling and assessment of the quality of mixing (mixing is considered satisfactory when the following condition is met: for dielectric particles conductor particles -

[0023] A significant distinguishing feature of this method from its prototype is that, when assessing the mixing quality in the claimed technical solution, the electrical characteristic of the polymer composite solution—its specific electrical resistance, which characterizes the distribution of filler particles within the polymer composite solution—is measured. This distinctive feature allows for assessing the mixing quality of filler particles of any color in the polymer solution, including white particles with a high reflectance coefficient of ρ ≥ 0.6, thereby expanding the functionality of the method for assessing the mixing quality of polymer composite solutions.

[0024] The implementation of the distinctive essential feature of the claimed method from the prototype allows for obtaining a technical result that allows for expanding the functionality of the method for assessing the quality of mixing of polymer composite solutions and assessing the quality of mixing of filler particles of any color in a polymer solution

[0025] Thus, the claimed technical solution has distinctive essential features from the prototype method and thus meets the invention criteria of significant differences and novelty.

[0026] Brief description of drawings

[0027] Fig. 1. Equipment for assessing the quality of mixing of polymer composite solutions: 1 - device E7-11; 2 - measuring device.

[0028] Fig. 2. Measuring device: 3 - body; 4 - central electrode; 5 - base; 6 - bolt; 7,8 - measuring rod; 9 - washer; 10 - nut.

[0029] Fig. 3. Dependence of strength σ рfrom the specific volume electrical resistance nanocomposite of elastomer F-40S filled with ceramic nanoparticles (Al2O3).

[0030] Fig. 4. Dependence of strength σ р from the specific volume electrical resistance nanocomposite of elastomer F-40S filled with aluminum nanoparticles.

[0031] Fig. 5. Mold-tool for producing polymer films: 11 - support plate; 12 - frame-stencil; 13 - film.

[0032] Implementation of the invention

[0033] The claimed method is implemented using the E7-11 device and a measuring device of an original design (Fig. 1). The E7-11 device is designed to measure electrical capacitance, inductance and resistance. The measuring device (Fig. 2) includes a housing 3, a central electrode 4 and a base 5. The housing 3 is made of a pipe of the 76×8×50kr - B - 10 grade GOST 32528-2013, the central electrode 4 is made of steel 40X GOST 4543-2016. The base is made by 3D printing from PETG plastic. The housing 3 is pressed into the base 5 with zero interference. Bolt 6 is screwed into the end of central electrode 4. Electrical resistance is measured by connecting the clamps of the E7-11 device's connecting cable to measuring rods 7 and 8, which are attached to bolt 6 and housing 3, respectively. The central electrode is connected to base 6 via washer 9 and nut 10.

[0034] The controlled solutions were solutions of elastomer varnish F-40S (TU 6-06-246-92) filled with dispersed metal and ceramic nanoparticles.

[0035] F-40S varnish (TU 6-06-246-92) is a solution of a rubber composition and modified phenolic resin in an organic solvent. F-40S varnish is a transparent brown liquid without mechanical inclusions, characterized by the following indicators [5]:

[0036] - mass fraction of dry residue - 20%;

[0037] - shear bond strength with steel at 20°C of at least 5.0 MPa. F-40 varnish composition:

[0038] 1) FKU resin (phenol-formaldehyde resin based on substituted phenol of vinyl acetylene structure) - 8 wt.%;

[0039] 2) synthetic butadiene-nitrile rubber grade SKN-40S - 12 wt.%;

[0040] 3) technical acetone, GOST 2768-84 - 80 mass%.

[0041] Al2O3 (α-phase) aluminum oxide nanoparticles were used as the first filler. The material was produced by electrical explosion of an aluminum conductor in an oxygen-containing atmosphere. Table 2 presents the parameters of the aluminum oxide nanopowder [2].

[0042]

[0043] Composition of the first nanocomposite: elastomer F-40S (TU 6-06-246-92) - 100 parts by weight, aluminum oxide nanopowder (TU 1791-003-36280340-2008) - 0.1 parts by weight.

[0044] Aluminum nanopowder (70) was used as the second filler. Aluminum nanopowder (70) was obtained by sputtering a metal conductor in an argon atmosphere and then passivated with a slow flow of dry air [2]. Table 3 presents the parameters of aluminum nanopowder (70).

[0045]

[0046] Composition of the second nanocomposite: elastomer F-40S (TU 6-06-246-92) - 100 parts by weight, aluminum nanopowder (TU 1791-003-36280340-2008) - 0.075 parts by weight.

[0047] The manufacturer of nanopowders is Advanced Powder Technologies LLC.

[0048] Determination of the minimum rejection level

[0049] The minimum rejection level was determined experimentally.

[0050] The nanocomposite components were weighed on a VK 3000.1 laboratory scale. The selected solution of unfilled F-40S elastomer was poured into a glass container, then the nanopowder was added, after which the composite was mixed with a mechanized stirrer with a working element rotation speed of: for aluminum oxide nanoparticles n = 900 min -1 , aluminum - n = 1300 min -1 . Mixing time t = 1.0; 3.0; 4.0; 5.0; 6.0 and 7.0 min.

[0051] After mixing, the nanocomposite solution was poured into the internal cavity of housing 3 of the measuring device to the required level. Two solution level marks are marked on the inner surface of the housing: the first level corresponds to a volume of 25 ml, the second to 50 ml.

[0052] In each of the six modes of mixing the nanocomposite solution, the electrical resistance R of three samples of nanocomposite solutions was measured and the measured values ​​were converted into values ​​of specific volume resistance using the formula [6]

[0053]

[0054] where - specific volume electrical resistance, Ohm x m; R -

[0055] resistance of the composite solution, Ohm; D and d are the diameter of the housing (inner) and the central electrode, m; H is the height of the composite solution level, m.

[0056] Then the average value of the specific volume resistance was determined

[0057] Rectangular films measuring 50×10×0.15 mm were produced from nanocomposite solutions. The working length of the films was 30 mm [1]. To obtain the films, a special mold-tool (Fig. 5) was used, consisting of a support plate 11 and a stencil frame 12 (material - Steel 3 GOST 380-94). The dimensions of the stencil frame are 130×100×0.5 mm. The stencil frame has three windows measuring 60×15×0.5 mm.

[0058] The tooling components were degreased twice with acetone and dried for 10 minutes. To prevent films 13 and stencil frame 12 from sticking to support plate 11, the latter's surface was covered with food-grade aluminum foil (GOST 32582-2013). Support plate 11 was then installed on a pre-set surface plate (GOST 10905-86). Frame 12 was placed on support plate 11, and the frame windows were filled with sublayers of the polymer solution using a #3 brush. Each sublayer was dried for 20 minutes.

[0059] The heat treatment of the samples was carried out in a SNOL-3.5,3.5,3.5 / 3 drying oven in stages: first stage: T=50°C for 1 hour; second stage: T=150°C for 2 hours. After heat treatment, the samples were conditioned for 24 hours at a temperature of 20°C.

[0060] The specimens were tested on an IR 5082-50 tensile testing machine. Load-deformation diagrams were recorded. The loading rate during testing was constant at 5 mm / min.

[0061] Film strength calculated using the formula

[0062]

[0063] where - breaking load, N; A - cross-sectional area of ​​the film, mm 2 .

[0064] Based on the test results, a graphical dependence of the strength of the samples was constructed under uniaxial tension from the specific volume resistance At the minimum permissible strength of the nanocomposite the minimum rejection level for specific volume resistance for a nanocomposite solution with ceramic nanoparticles is (Fig. 3), for a solution of a nanocomposite with aluminum nanoparticles is (Fig. 4).

[0065] Bibliographic data

[0066] 1. Lee, R.I. Method for assessing the quality of mixing polymer composite solutions [Text]: Russian Federation Patent for Invention No. 2833364. Claimed 04.05.2023. / Lee R.I., Kiba M.R., Erokhin V.E. / / Published 20.01.2025. - Bulletin No. 2.

[0067] 2. www.nanosized-powders.com

[0068] 3. Code of Practice for Design and Construction. Natural Lighting of Residential and Public Buildings. SP 23-102-2003.

[0069] 4. Fundamentals of lighting engineering: a tutorial / A.Ya. Leivi, A.A. Shulginov; edited by A.A. Shulginov. - Chelyabinsk: Publishing center of SUSU, 2016.-71 p.

[0070] 5. https: / / institut-plastmass.tiu.ru / p32507115-fenolnye-smoly-laki.html.

[0071] 6. Shipulin, M. A. Non-destructive testing of the quality of fixed joints of rolling bearings of agricultural machinery restored with polymer composite materials [Text]: dis. ... Cand. of Engineering Sciences: 05.20.03: / Shipulin M. A. - Michurinsk, 2012. - 141 p.

Claims

A method for assessing the quality of mixing of polymer composite solutions, including measuring an assessment quality parameter, rejecting composite solutions with unsatisfactory mixing quality by comparing the value of the assessment quality parameter with a minimum rejection level, characterized in that the assessment quality parameter of mixing is the specific electrical resistance.

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