CC BY
27
UDC 678.01
V. E. Kablov, O. M. Novopoltseva, V. G. Kochetkov, N. V. Kostenko, K. A. Kalinova, G. E. Zaikov
INFLUENCE OF TRANSITION METAL COMPOUNDS ON FIRE AND HEAT RESISTANCE
OF RUBBER MIXTURES
Keywords: elastomers, rubbers, fillers, modifying additives, d-elements, fire resistance.
Development of modern industry requires an increase in the temperature limit of exploitation of elastomer materials that is achieved by using new components that provide the flowing ofphysical and chemical transformations enhancing their operational stability. In this paper, a possibility of using metal oxides with variable valence to create elastomer compositions has been shown. Impact of the oxides on flame and heat resistance of rubbers based on general-purpose raw rubbers has been considered.
Ключевые слова: эластомеры, резины, наполнители, модифицирующие добавки, d-элементы, огнестойкость.
Развитие современной промышленности требует увеличение температурного предела эксплуатации эластомерных материалов, что достигается использованием новых компонентов, обеспечивающих протекание физико-химических превращений, способствующих повышению их эксплуатационной стойкости. В работе показана возможность использования оксидов металлов с переменной валентностью для создания эластомерных композиций. Рассмотрено их влияние на огнетеплостойкость резин на основе каучуков общего назначения.
Preview
Development of modern industry requires an increase in the temperature limit of exploitation of elastomer materials including extreme conditions in the field of thermal decomposition which is achieved by using new components that provide the flowing of physical and chemical transformations enhancing their operational stability.
Additives that can change their structure under external influences (e.g., layered, intumescent additives, etc.) play an important role in improvement of rubber operational stability [1, 2].
In extreme operating conditions, at temperatures near and above the temperature working capacity of a material, functionally active fillers can play a stabilizing role in thermal destruction of the material [1, 2].
One of the perspective directions for solving the problem is to use intumescent and highly dispersed metal-containing fillers in elastomeric compositions, as also aluminum silicates, fillers with a catalytic activity, highly dispersed silicon carbide [3-5] including the compounds of the transition metals.
Some of the metals related to d-elements have properties which enable to apply them as protective and wear resistant coatings, a fireproof material for aircraft and rocket engines, a component of multilayer coatings for laser mirrors and beam splitters [6], for production of refractories for increasing campaign in furnaces for melting glass and aluminum. Such refractories are used in the metallurgical industry for gutters, glasses in the continuous casting of steel and crucibles for melting rare earth elements. They are also used in some ceramic-metal coatings, which have high hardness and resistance to many chemicals and keep short-term heating up to 2750 °C.
It is also known the use of metal organic compounds containing these elements as a crosslinking agent for polymers [7].
Experimental Results and Discussion
The research was devoted to a study of influence of transition metal compounds on the properties of rubber mixtures and their vulcanizates based on general-purpose raw rubbers.
Rubber mixtures were prepared according to the standard recipes based on styrene-butadiene raw rubber using the sulfur vulcanizing group with partial replacement of carbon black on the analyzing compounds (Table 1).
Table 1 - Filler content in the studied compositions
Filler Number of a rubber mixture
Z-0 Z-1 Z-2 Z-3 Z-4 Z-5
Carbon black П-324 40 35 30 25 20 15
ZrO2 - 5 10 15 20 25
Kinetic parameters of rubber mixtures were determined by using Monsanto 100S rheometer. Research has shown that introduction of transition metal compounds increases the induction period, but it practically does not change the vulcanization rate (Fig. 1). In addition, there is a reduction of elastic-strength properties, however, resistance to thermal-oxidative ageing and resistance to flame action rises (Table 2). To estimate fire resistance, the dependence of temperature on the unheated sample surface from the exposure time of the plasma torch flame was determined (Fig. 2). Temperature on the sample surface was generated about 2000 °C.For the experimental samples the heating time increases and degradation occurs at higher temperatures compared with the control sample.
When the experimental samples are exposed to flame, a dense and flame retardant coke which protects the sample from burning is formed on their surface (Fig. 3).
Fig. 1 - Kinetic curves of vulcanization: 1 - Control rubber mixture Z-0; 2 - mixture Z-1; 3 - mixture Z-2; 4 - mixture Z-3; mixture Z-4
Table 2 - Physical and mechanical properties of vulcanizates
Parameter Number of a rubber mixture
Z-0 Z-1 Z-2 Z-3 Z-4
Tensile strength (fp), MPa 18,0 14,0 15,0 12,2 13,3
Elongation at break, % 420 410 590 560 490
Relative residual elongation after fracture,% 12 9 11 9 9
Change of parameters after aging (100 °C x 72 hrs), %: A/P As -45 -67 -36 -61 -40 -63 -34 -64 -31 -59
Linear combustion velocity, mm/min 24,5 6 23,96 22,72 15,96 15,18
Warm-up time of the sample surface to 100 °C, sec 60 60 60 80 90
Time of burning-out of the sample, sec 100 110 110 120 130
Vulcanization mode:145°C, 30min
Fig. 3 - View of carbonized surface of an experimental vulcanízate sample (coke layer) under the flame exposure
Conclusion
So, the research has shown that the investigated transition metal compounds can be used to effectively enhance the fire resistance of elastomeric materials and reduce their cost.
References
1. Kablov V.F. System technology of elastomeric materials -integration processes in development of materials and products // Proceedings of XV International scientific and practical conference «Rubber industry. Raw materials, materials and technologies» (Moscow, 2009), P. 4.
2. Kablov V.F., Novopoltseva O.M., Kochetkov V.G. [et al]. Impact of perlite filler on heat resistance of rubbers based on ethylenepropylenediene raw rubber // Modern Problems of Science and Education. 2013. № 3, URL: www.science-education.ru/109-9370
3. Kablov V. F., Novopoltseva O. M., Kochetkov V.G. [et al]. Heat protective coatings containing perlite // International Journal of Applied and Fundamental Investigations. 2012. № 1. P. 174.
4. Lifanov V.S., Kablov V.F., Novopoltseva O.M. [et al].Study of elastomeric materials with microdispersed silica carbide wastes // Modern Problems of Science and Education. 2013. № 4. URL: www.science-education.ru/110-9971
5. Lifanov V.S., Kablov V.F., Lapin S.V., Kochetkov V.G., Novopoltseva O.M. Elastomeric materials with microdispersed silica carbide wastes// Kauchuk i rezina, 2013. №6, pp. 8-10.
6. E.G. Rakov, V.V. Golubkov, Hyu Van Nguen. Development of carbon nanomaterials// Herald of National Research Nuclear University "MEPhl", 2012. Vol. 1, № 2, pp. 167-171.
7. S.J. Monte, Kenrich Petrochemicals. Titanates and zirconates in thermoplastic and elastomer compounds // Rubber World, 2012, pp. 40-45.
Fig. 2 - Dependence of temperature on the unheated sample surface on the heating time
© V. Е. КаЫоу - д.т.н., проф., зав. каф. химической технологии полимеров и промышленной экологии, директор ВПИ (филиал) ВолгГТУ; kablov@volpi.ru; О. М ^УороШеуа - д.т.н., проф., зам. зав. той же кафедры, nov@volpi.ru; V. О. Kochetkov - асп. той же кафедры, nikol-kosten@yandex.ru; N. V. Kostenko - магистр той же кафедры; К. А. КаИпоуа -студ. той же кафедры; О. Е. Zaikov - д-р хим. наук, проф. каф. технологии пластических масс КНИТУ.
