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Vapaev Murodjon Dusummatovich, doctoral candidate, basic doctoral studies of the department "Technology of plastics and high-molecular compounds" of the Tashkent Institute of Chemical Technology Uzbekistan, Tashkent
Akhmadzhonov Sardor Akhmadzhonovich, master of Tashkent Institute of Chemical Technology Uzbekistan, Tashkent
Teshabaeva Elmira Ubaidullaevna, doctor of Technical Sciences, professor, envious of the department "Technology of plastics and high-molecular compounds", Tashkent Institute of Chemical Technology Uzbekistan, Tashkent
Ibadullayev Akhmadzhon, doctor of technical sciences, professor, envious of the department "Chemical technology of oil and gas processing", Tashkent Institute of Chemical Technology Uzbekistan, Tashkent
E-mail: Ulug85bek77@mail.ru
INVESTIGATION OF MODIFIED ANGREN CAOLINE AS FILLING AND ACTIVATOR OF VULCANIZATION OF SOME ELASTOMERIC COMPOSITIONS
Abstract: This article presents the results of research into the feasibility of using modified kaolin as a filler and activator of rubber compounds based on butadiene nitrile rubbers. It is shown that it is influenced by the kinetics of the vulcanization process of rubber compounds on technological and technical parameters of elastomeric compositions. It was found that the optimum content of the modifier and Angren caolin in the composition of rubber compounds.
Keywords: rubber, rubber compound, ofAngren caoline, modification, activator, vulcanizing agent.
Introduction
On the base of analysis of literature of investigation of morden state of technological process of modification elastomers and compozitional materials on their base by filling it was determined that the most perspective direction at development of such compositions at present time is searching of multifunctional filling and elaboration of technology of obtain compositional elastic materials and articles on the base with specifical properties [1].
In accordance with this the aim of this investigation is concluded in modification ofAngren caoline by su-turated adsorbent ofprimery processing ofoil and gas.
Оbjects and methods of investigation. For car-ring out of this investigation copolymer butadienni-tryl- acrylic acid was used. Rubber mixtures on the base of this elastomer were prepared on laboratorial at 30-35 °C and then they were vulcanization on press. Modified and reached caoline of Angren deposite was used as vulcanizational agent, activater and filling. Technological properties of rubber mixtures have been investigated according to corresponded GOSTs; kinetics of vulcanization of rubber mixtures was investigated on reometr Mansanto 100-4L.
Discussion of obtained results. It is khown that vulcanization of elastomers with functional groups
sP
- C -o- earring out by action of Ca(OH)2 is characterised by presence in structure of forming rubbers side by side with ionic also cross-linking bonds. Their formation is course by fact that activater of salt vulcanization at the same time is used in by reaction of pereeterification with functional groups of elastomer. It was determined that threeethanolamine is vulcani-zational agent of elastomers which were structured by functional groups at temperatures don't lower than 180 °C only in presence of activator - Fe(OH)3.
On the base of carring out investigations [2; 3] and experimental investigations it was determined that Angren caoline with out correspouding physico-chemical modification and treatment can't be used in production of compositional elastomeric materials. Angren caoline contains to 2-3% of Fe2O3 (Table 1) what negatively influence on the complexe of properties of rubber compositions and articles from them. The main demand produced to mineral fillings at production of compositional elastomeric and articles from them is that containe of Fe2O3 was didn't more than 0.3%.
In result of carring out experimental investigations it was determined the possibility of modification of reached Angren caoline by saturated absorbent of primary processing of oil and gas, which is
presented by self suspension of yellow couler with temperature of boiling 541K.
Modification of Angren caoline was carried out by following way: enreached caoline has been modified by liquid modificator and was dried after this at temperature 373 + 5 °C befor constant mass. Carring out investigations have allowed to prepose, that using of modified Angren caoline has allowed to proposed principally new approach for construction of high-filling elastomeric compositions with specifical properties on the base of synthetical butadiennitrile elastomer (rubber).
Table 1.- Chemical composition of Angren caoline
Name of components Contain, was%
SiO2 51.20
Al2O3 43.40
TiO2 0.60
CaO 0.21
MgO 0.30
pe2°3 2.22
SO3 0.21
Cl" 0.01
SO-2 4 0.05
Water - soluble salts 0.10
Moisture 2.7
Figure 1. Dependence on kinetics of vulcanization of rubber mixtures on the base rubber CKH-26, containing 40 mass.% by modified Angren caoline (content of modificator (%):1-5%; 2-10%; 3-15%)
For investigation of influence of modified Angren caoline on the complex of properties of compositional elastomer materials some standart aproach-ers have been choosed which were elaborated on the base of synthetical butadien-styrol rubber. In this aproachers activator, vulcanization agent and technical carbon have been move away.
Kinetical curves of formation of cross - linking bonds have witnessed that vulcanization of rubber mixtures by modified Angren caoline has carried out intensivelly.
It was shown that Angren caoline has promoted to maximal absorbtion of modificator molecules and also has activated by Fe2O3 formation of more perfect regulating vulcanizational structures. This effect has shown that modified caoline not only has activated but also has accelerated processes of structuring processes. Very important advantage of modified Angren caoline is the fact it simultaneously has plaied role of filling, vulcanizational agent and activator what has influence on the nature and number of cross-linking bonds and properties of elastomeric compositions (Table 2).
Table 2.- Influence of modified caoline on structure of vulcanizational net of rubbers on the base CKH-26
Contain of filling and modificator Type of bonds,%
-C-Sx-C- -C-S-S-C- -C-S-C- -C-C-
40 mass.%. of Angren caoline, modified by 5% of modificator 30 26 25 19
40 mass.%. of Angren caoline, modified by 10% of modificator 20 25 27 36
40 mass.%. ofAngren caoline, modified by 15% of modificator 22 26 28 24
20 mass.%. ofAngren caoline, modified by 10% of modificator 18 23 25 34
In result of vulcanization of elastomer filling increasing stability of undervulcanization; higher
by modified caoline it was determined that it is mechanical characteristics, residual deformation of
characterised by number of advantages in com- pressing, water-stability and also frost-resistance
parasion with using vulcanization agent (S+ZnO): (Table 3).
Table 3.- Technological and physico-mechanical properties of rubbers on the base of elastomer CKH-26 filling by modified Angren caoline
№ Properties Properties of composition
Initial composition Composition filling by modified Angren caoline
1 2 3 4
1. Time of begining of undervulcanization at 120 oC, min. 28 45
2. Strain at elongation 300%, MPa. 21.5 13.9
3. Conditional stability at tension, Mpa 24.6 29.2
4. Relative elongation at break,% 386 500
5. Relative residual deformation,% 13 13
In composition of vulcanizational system can ment of properties of rubber compositions in par-be introduced some additional cross-linking agents ticular the residual deformation of pressing and wa-including peroxides proving of following improve- ter - resistance (table 4).
Table 4.- Technological and some physico-chemical properties of rubbers filling by combinational vulcanization reagen
1 2 3 4
6. Temperature of fragility, oC -40 -58
7. Coefficient of frost-resistance (K) at -25 oC 0.10 0.44
8. Residual deformation of pressing (24 h. x x 100 oC),% 71 35
Degree of equlibrium swelling,% in: water (70 oC x 24 h.);
9. water (100 oC x 24 h.); 6.2 1.5
mixture of isooctane: tolyol = 70:30 26.0 15.0
(20 oC x 24 h.) 34.4 33.0
Properties of composition
№ Properties Initial composition Composition filling by modified Angren caoline +peroxide
1. Time of begining of undervulcanization at 120 oC, min. 44 44
2. Time of vulcanization at 180 oC, min. 40 60
3. Strain at elongation 300%, MPa 18.8 19.8
4. Relative strain at elongation, MPa 21.4 25.1
5. Relative elongation at break,% 330 335
6. Relative residual deformation after break,% 7 6
7. Temperature at fragility, oC -57 -61
8. Residual deformation of pressing(l00 oC x x 24 h.),% 31.0 31.7
9. Degree of equlibrium swelling,% in: water (100 oC x 24 h.):
mixture of isooctane: tolyol = 70:30 7.56 7.4
(20 oC x 24 h.) 36 33
Resume. Obtained vulcanizating systems can be effectivly used fo manifucture of oil-benzo-stable articles different types by method ofvulcanization. At this owing to markedly increasing velosity of vulca-
nization of rubber articles on the base of syntetical butadiennitrilic elastomers containing modificated Angren caoline this process can be carried out at lower temperatures (150 oC).
References:
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3. Ибадуллаев А., Тешабаева Э. У Негматов С. С., Таджибаева Г. С. Исследование физико-механических свойств минеральных наполнителей и методы их модификации // Журнал «Композиционные материалы» - Ташкент, 2006.- № 1.- С. 27-29.
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