Method of evaluating reinforcement properties of soot in rubber

FIELD: chemistry.

SUBSTANCE: method involves filling the surface of soot with a polymer and determining the polymer adsorption value of the soot, where the polymer used is rubber. Soot dispersion is mixed with a rubber solution. Sieve diametres of the soot aggregates are determined. The specific surface of the soot is determined and relative wear resistance of the rubber is calculated from the given relationship.

EFFECT: faster and high information content of analysis.

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The invention relates to methods of technical analysis carbon (soot) and can be used in the development of technology for production of new grades of carbon black for rubber. The main part of the carbon consumed in the rubber industry, is used to improve physical properties, improve durability and reduce the cost of rubber compounds. Improving the physical properties of rubbers, namely strength and durability, is determined by the reinforcing properties of the filler is carbon black.

There is a method of assessing the reinforcing properties of carbon black in the rubber on the end result - mechanical properties of rubbers (ultimate tensile strength, modulus at 300%elongation, relative elongation of the sample at break), made with the test sample and the standard soot IRB-7. To define them prepare standard rubber mixture according to the recipe ASTM D 3191 based on the best choice of rubber or ASTM D 3192 based on natural rubber using ingredients according to the method of ASTM D 3182-07. Rubber compound condition within 1-24 h, vulcanized, again condition of vulcanized rubber for 16-96 h and test their mechanical properties according to the method ASTM D 412. The results are expressed as the difference between the values obtained for mixtures with the test sample and the standard soot IRB-7. The disadvantage with the person is significant complexity, the material, the scatter of the experimental results, due to the quality of prepared rubber compound, different degree of dispersion of the filler and the method of obtaining a rubber mixture (the number of stages, the process temperature, time, mixing).

There is a method of assessing the reinforcing properties of carbon black in the rubber (Lezhnev N.N., Yakuhin K.A., Krasilnikova, M.K. way of assessing the reinforcing properties of carbon black in the rubber // A.S. 442919, BI No. 33, 1975) determination of the heat of interaction with soot model hydrocarbon (low-molecular olefin), adopted as the standard rubber when filling them 2-30% of the surface of carbon black. However, this method is long (5-6 hours), requires special purpose devices (calorimeter or carbomer for registration of adsorption isotherms) and does not give information about the relative durability of rubbers.

There is a method of assessment index of wear resistance of rubber on the analysis of rubber and filler. Determine the amount of bound filler in rubber compounds rubber, form factor (anisometry) and the volume of the primary soot aggregates, whose values are calculated index of wear resistance rubber (Dannenberg E.M. // Rubber Chem. Technol. 1986, V.54, No 3, P.497-511). The form factor F1and the volume V1primary aggregates of carbon black is determined by processing of electron microscopy images of primary aggregates by the Yu program PC Image Analysis by the method of ASTM D 3849. The disadvantage of this method is the considerable complexity (at least 6-8 hours on one analysis) and the use of special equipment (rubber mixer for the manufacture of rubber compounds, electron microscope).

Closest to the claimed is a method of assessing the reinforcing properties of carbon black (A.S. USSR №1756324, prototype). The method includes filling the surface of carbon black polyethylene glycol, determination of the rate of adsorption of a series of polyethylene glycols with soot and evaluation using this indicator reinforcing properties of carbon black. This method also long (2-4 hours), requires expensive imported reagents (monodisperse molecular standards glycols) and does not give information about the relative durability of rubbers.

The aim of the invention is the reduction of time for analysis and determination of the relative durability of rubbers.

The proposed method of assessing the reinforcing properties of carbon black in the rubber includes filling the surface of carbon black polymer, which is used as the rubber, the determination of the rate of adsorption of the polymer soot, mixing the carbon black dispersion with a solution of rubber, the definition of sieve diameters of soot aggregates, the degree of dispersion of carbon black and the calculation of the relative wear resistance of rubber by the formula

And1/2=a{(100·k1·G1·Dv3(1)·Dw3(2))/(k 2·G2·Dv3(2)·Dw3(1)} +

where is the abrasion of the vulcanizates with reference soot And1and tested And2, %;

G - specific adsorption of rubber reference soot G1testing G2; g/m2;

Dvand Dw- average screen diameters of single units of the reference carbon black Dv(1)Dw(1)and tested Dv(2)Dw(2);

k is the degree of dispersion of the reference carbon black (k1) and test (k2), %;

a and b are empirical coefficients (a=0,53; in=48).

The method is also distinguished by the fact that as use rubber isoprene or the best choice.

In the proposed method are applied directly to the rubber used to obtain rubbers, and General laboratory equipment. Preparing a dispersion of carbon black in an organic solvent (toluene, benzene, xylene) at high speed stirrer with glass beads and determine the degree of dispersion (E. Strizhak, Razzakova GI Study of agglomerates of carbon black in the rubber compound. Part 1. An improved method of optical microscopy for analysis of agglomerates // young Russia. Advanced technologies in the industry: mater. II the age of three. Molodin. scientific-technical. proc. - Omsk: Publishing house of Omsk University, 2009. - CN. - S-224, 248).

Prepare 0,2%solution of rubber in the same RA is the solvent, as the dispersion of soot.

Mix the dispersion of carbon black with a solution of rubber, stand 8-12 minutes and filtered. The concentration of the rubber before and after adsorption of soot is determined using an interferometer or viscometer according to calibration curve. Determine the value of the specific sorption of rubber soot. The analysis duration is 1 hour, the error (coefficient of variation) 3%.

Define screen diameters of aggregates of carbon black (Stacy C.J., Johnson R.N., Kraus G. Effect of carbon black structure aggregate size distribution on properties of reinforced rubber. - Rubber Chem. technol., 1975, V 48, No.2, P.538-547). To do this, pass the same volume of aqueous suspension of carbon black with the addition of anionic surfactants through the microfilters (membrane NUCLEPORE) with hole diameters from 0.1 to 0.6 μm by 0.1 μm and determine the concentration fractions of primary soot aggregates using fotoelektrokalorimetry (method optical weighting"). From the curve fractionation soot expect two average sieve diameter Dwand Dv. Scheme, clarifying concepts diameters of aggregates Dwand Dvshown in the drawing.

The duration of the analysis of the average diameter of the aggregates is 0.5 h, and the accuracy of their definition (coefficient of variation) of 6.8%, which is acceptable for the control method of analysis of such polydisperse powders as soot.

The use of the proposed method of assessing the reinforcing properties of soot is based on the ability of aggregates of carbon black to hold the rubber as adsorbed on the surface, and absorbed by the aggregates. The amount of rubber in the adsorbed layer in proportion to the activity of carbon black relative to the rubber and the specific external surface of carbon black when it is connected to the macromolecules of rubber, i.e. a high degree of dispersion of carbon black in the dispersion, it is difficult to achieve because of the parallel process redispersible soot. The balance of these two processes of dispersion and redispersible characterized by the degree of dispersion of carbon black. Analytical method evaluation absorbed by the aggregates of carbon black rubber does not exist. But this part of the rubber is mechanically protected from weak deformation and is a "reserve" strength of rubbers with their large deformations, especially when abrasion rubber. Thus, the index of specific adsorption of the polymer soot simultaneously characterizes the adsorption and absorption capacity of soot when the reached degree of its dispersion. Potential absorptive capacity soot and characterizes the volume of voids in the unit, which is proportional to the ratio sieve diameters of aggregates Dw3/Dv3.

Examples 1-8 (1-5)

Table 1
Brand samples of carbon black used is presented in examples 1-8
Non of the examples in tables 2-5
12345678
Brand soot sample
N330 (standard)N220Work No. 121N326P 245To 354P 145 sample 1P 145 sample 2

1. Preparation of rubber compounds filled with the reference and test Sagami, their vulcanizates and their physico-mechanical properties.

Cook on mixing rollsstandard rubber mixture at the ratio of the amount of load rollers, equal 4,00.

Rubber compound A (parts by weight)

Natural rubber (NC) SMR-L100
Stearic acid3
Zinc oxide5
Dibenzothiazepine 0,6
Sulfur gas2,5
Soot (table 1)50

Rubber compound B (parts by weight)

Butadiene-styrene rubber SKS-ARC100
Stearic acid1
Zinc oxide3
Sulfur gas1,75
TWS (sulfenamid T)1
Soot (table 1)50

Vulcanized rubber mixture under the following conditions:

Rubber compound And 30 minutes at a temperature of 145°C;

Rubber mixture B in 50 min at a temperature of 145°C.

Condition resulting vulcanizates a and B at a temperature of (23±2)°C for 48 hours before testing.

Determine the friction when sliding on renewable surface shopper Sabahu according to GOST 23509-79. Test data samples rubbers (examples 1-8) shown in table 2 and 3.

Table 2
Physico-mechanical whom their properties of vulcanizates And based NC
IndicatorsExamples
12345678
Abrasion, cm3/m·10-32,62,252,02,922,41of 2.262,1to 2.06
The relative wear resistance, %10011613089108115119117

Table 3
Physico-mechanical properties of vulcanizates B based on the SCS-ARC
IndicatorsExamples
12 378
Abrasion, cm3/m·10-32,4to 2.061,831,921,91
The relative wear resistance, %100116,5RB 131.1125,0125,7

2. The proposed method.

Preparation of dispersion of carbon black. A portion of soot mass of 1.26 g placed in the container of a high speed stirrer, add 50 cm3glass beads of 2 mm diameter, poured 100 g of an organic solvent (toluene, benzene or xylene). Mix the dispersion of carbon black in an organic solvent at high speed stirrer with glass beads for 10 minutes and determine the degree of dispersion.

Preparation of a solution of rubber in an organic solvent. Prepare 0,2%solution of rubber in the same solvent as the dispersion of carbon black (initial concentration of Cabout(g/g).

The determination of the specific adsorption of rubber soot (G). Mixed in a flask with a capacity of 50 cm311 g of a dispersion of carbon black and 20 g of a solution of rubber (m1), shake the contents of the flask for 8 minutes and Phil is trout. Determine the concentration of the rubber after adsorption of soot (Cp(g/g) using an interferometer or viscometer according to calibration curve.

The rate of adsorption of rubber soot G, g/m2, calculated by the formula

G=(Co-Cp)·m1/SNR·m2,

where m2- soot mass in the sample variance, g;

SNR- specific external surface of carbon black, m2/g, determined according to GOST 25699.2-90.

The concentration of the rubber after adsorption of Cp(g/g) calculated taking into account the dilution of the solution, rubber solvent from the dispersion of soot.

Definition screening of soot diameters Dwand Dv. Determine the average screen diameters of the tested and reference soot. This is prepared with the help of acoustic cavitation 44 KHz on the device UZDN-2T with open emitter for 10 min, the suspension of carbon black concentration of 0.001% in aqueous solution of surfactant-1019 concentration of 10-5mol/kg, Then the suspension is filtered through a membrane filter NUCLEPORE with a pore diameter of 0.9 µm. The obtained filtrate portions 5 cm3filtered through membranes with pore diameters 0,1; 0,2; 0,3; 0,4; 0,5 and 0,6 μm. The filtrates determine the optical density Diin a cell with a thickness of 1 cm at a wavelength of 490 nm on fotoelektrokalorimetry.

Average sieve diameter of aggregates of carbon Dw, µm calculated by the formula

di=(di+di+1)/2,

where di- the average value of the diameters of the holes of the membrane;

ΔA and A is calculated by the formula

ΔA=Ai-Ai+1,

A=Di/D0.6,

where Dfor 0.6- the optical density of the suspension on a filter with a pore diameter of 0.6 μm.

Average sieve diameter of aggregates of carbon Dv, µm calculated by the formula

Calculated values of the relative wear resistance of vulcanizates based on NCS and SCS by the formula

And1/2=0,53{(100·k1·G1·Dv3(1)·Dw3(2))/(k2·G2·Dv3(2)·Dw3(1)}+48.

The results of the calculations are shown in table 5.

Compare calculated (table 5) and experimental (table 2, 3) values of the relative abrasion resistance of the vulcanizates. Their error ν, %, calculated according to the formula

ν, %=(Andi/j expertAndi/j Rasch)/Andi/j expert.

Table 4
Experimental results determination of sieve diameters of the aggregates, the degree of dispersion and specific adsorption soots
Indicators Examples
1 (standard)2345678
brand soot sample
N330 (standard)N220Work No. 121N326P 245To 354P 145) sample 1P 145 sample 2
SNRm2/g76101,31087610692114,8115
Dw, mcm0,3350,3010,2080,2900,3650,2000,2020,200
Dv, mcm0,243 0,2470,1780,2300,2900,1670,1650,161
k in toluene, %9394939295969693
k in benzene, %9495939196969690
k metaxalone, %9495929096959588
G·103, g/m2(NC in toluene)0,820,690,790,530,660,710,750,78/td>
G·103, g/m2(NC in benzene)0,830,700,770,540,690,660,770,80
G·103, g/m2(NC in metaxalone)0,800,710,810,550,680,720,730,82
G·103, g/m2(SCS in toluene)0,710,620,710,470,590,640,670,70
G·103, g/m2(SCS in benzene)0,750,600,710,490,570,630,670,70
G·103, g/m2(SCS in metaxalone) 0,670,640,700,500,630,620,820,73

Table 5
Values are calculated relative abrasion resistance of the vulcanizates on the basis of the TC and SCS and relative errors of their determination.
Calculated relative wear resistance of the vulcanizates in % based on rubberExamples
1 (standard)2345678
JCBAndi/j, %100,0117,7133,893,5103,2120,6123,8129,4
ν,% 0-1-2-45-41-3
NCAndi/j, %100,0115,0130,7for 91.3105,9119,5118,4114,1
ν,%01-1-32-403

As can be seen from table 5, the absolute value of the calculated values of the relative wear resistance of rubber vary within wide limits, and the accuracy of their determination not exceed 5 Rel.%.

Using the proposed method at the enterprises producing and processing soot and engaged in development of technology for production of new grades of carbon black for rubber, not hard and will give an opportunity to advance, without the production of rubbers and their tests, to predict the synergistic effect of carbon black, namely the relative snooty the awn rubber with carbon black, when transferring production to another supplier or choice and input in the production of new grades of soot.

1. The way of assessing the reinforcing properties of carbon black in the rubber that includes filling the surface of carbon black polymer and determination of the rate of adsorption of the polymer soot, characterized in that the polymer used as the rubber, the carbon black dispersion is mixed with a solution of rubber, define screen diameters of soot aggregates, determine the degree of dispersion of carbon black and calculate the relative wear resistance of the rubber by the formula
And1/2=a{(100·k1·G1·Dv3(1)·Dw3(2))/(k2·G2·Dv3(2)·Dw3(1)}+b
where is the abrasion of the vulcanizates with reference soot And1and tested And2, %;
G - specific adsorption of rubber reference soot G1testing G2, g/m2;
Dvand Dw- average screen diameters of single units of the reference carbon black Dv(1)Dw(1)and tested Dv(2)Dw(2);
k is the degree of dispersion of the reference carbon black (k1) and test (k2), %;
a and b are empirical coefficients (a=0,53; b=0,48)

2. The method according to claim 1, characterized in that the quality of the rubber used isoprene or the best choice.



 

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2 dwg, 7 tbl, 2 ex

FIELD: weighing equipment; chemical mechanical engineering.

SUBSTANCE: method can be used for measuring content of binder in reel-up composite material produced by preliminary soaked thread. Method is based upon weighing. The constant values are determined according to the method as length of thread for specific type of items and value of linear density averaged for any reel before and after soaking by binder and reeling it up onto frame. Weighing is performed for item before reeling it up with soaked thread and after reeling-up and final polymerization of composite material to determine mass of composite. Basing upon the data received, content of thread is determined which value is subsequently used for finding mass content of binder in composite from relation of C=(M-LxT/M)x100%, where C is content of binder in composite, in mass percent; M is mass of composite, g; L is length of thread consumed for item, km; T is average arithmetic meaning of values of linear density of thread and its rests at any reel before and after impregnation, g/km.

EFFECT: higher stability of performance measures.

1 ex

FIELD: light industry.

SUBSTANCE: method comprises recording response of the material to be tested that represents an amplitude-frequency characteristic, calculating deformation characteristics, and determining the value of distributed mass of the vibrating part of the material. The response representing two amplitude-frequency characteristics is recorded for the same part of the material to be tested for various masses of two bodies that cause deformation. The deformation characteristics are calculated from equations of vibration theory for viscoelastic bodies.

EFFECT: enhanced precision and reliability.

FIELD: investigating or analyzing of materials.

SUBSTANCE: method comprises investigating threshold capabilities of the multi-layer polymeric material and determining maximum permeability of oil product and time period required for reaching the maximum permeability.

EFFECT: enhanced reliability.

1 dwg, 1 tbl

FIELD: investigating or analyzing of materials.

SUBSTANCE: method comprises preliminary conditioning of rubber specimens in paraffin hydrocarbon with 12-16 atoms of carbon in the atmosphere of neutral gas and in the fuel to be tested at a temperature of 130-150°C for 3-5 hours.

EFFECT: enhanced reliability.

1 dwg, 2 tbl, 1 ex

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