CC BY
32
UDC 678.01
V. F. Kablov, O. M. Novopoltseva, V. G. Kochetkov, N. V. Kostenko, A. G. Lapina, V. S. Lifanov, G. E. Zaikov, Kh. S. Abzaldinov
INVESTIGATION OF HEAT PROTECTIVE POLYMERIC MATERIALS CONTAINING
FUNCTIONAL FILLERS
Keywords: elastomers, rubbers, fillers, modifying additives, fire resistance.
Articles of elastomeric compositions are used in missilery, aircraft and marine engineering, including constructions for special purposes, operating at extreme temperatures. Therefore, of particular interest are polymeric composite materials with heat resistance above 200 ° C, the product of which can be operated for a long time at elevated temperatures. In this paper, the possibility of using functionally active fillers to create elastomeric compositions is shown. Their impact on flame and heat resistance of rubbers based on general-purpose rubbers has been considered.
Ключевые слова: эластомеры, каучуки, наполнители, модифицирующие добавки, огнестойкость.
Изделия на основе эластомерных композиций используются в ракетной, авиационной и морской технике, в том числе для сооружений специального назначения, действующих в условиях экстремальных температур. Таким образом, особый интерес представляют собой полимерные композиционные материалы с теплостойкостью выше 200°С, изделия из которых могут эксплуатироваться в течение длительного времени при повышенных температурах. Показана возможность использования функционально активных наполнителей для создания эластомерных композиций. Рассмотрено их влияние на огне- и теплостойкость резин на основе каучуков общего назначения.
Introduction
Articles made from elastomeric compositions used in the rocket, aircraft and marine engineering, including constructs for special purposes, operating at extreme temperatures. Therefore, of particular interest are polymeric composite materials with thermal resistance higher than 200 °C, the product of which can be operated for a long time at elevated temperatures.
Heat and flame resistance of polymer materials and articles thereof defined in engineering features such as flammability, ignition temperature and self-ignition, burning rate and flame propagation on the surface, smoke emission during combustion, toxic products of combustion and pyrolysis [1, 2]. It should be noted that the above characteristics are often contradictory and improving one property may be accompanied by other deterioration. Introduction of additives, substances that increase the heat and fire resistance of polymer materials usually results in some deterioration of physical mechanical, dielectric, and other operational and processing properties, as well as increasing the material cost. Therefore, increasing the heat and flame retardant properties of polymeric materials is the task to optimize the complex characteristics of the produced material.
One of the promising ways of increasing the thermal stability of these materials is to use a part of the elastomer compositions of intumescent (perlite, vermiculite, thermally expandable graphite) and highly dispersed fillers, including highly dispersed silicon carbide [3, 4].
The purpose of research is to find ways to improve fire and heat resistance of elastomeric materials based on various types of rubbers by introducing fillers.
Experimental
Objects of investigation are vulcanizates based on SBR rubber with sulfuric vulcanizing group (Table
1) [4, 5]. Perlite and microparticulated silicon carbide are suggested as fillers.
Table 1 - Recipes of investigated rubber compounds
Ingredients Dosage, pbw. of 100 pbw. rubber
Cont rol С1 С2 С3
SKMS-30-ARKM-15 100,0 100,0 100,0 100,0
Vulcanizing group 9,5 9,5 9,5 9,5
Carbon black n324 40,0 30,0 25,0 20,0
Silicon carbide - 10,0 15,0 20,0
Perlite - - - -
Ingredients Dosage, pbw. of 100 pbw. rubber
Cont rol П1 П2 П3
SKMS-30-ARKM-15 100,0 100,0 100,0 100,0
Vulcanizing group 9,5 9,5 9,5 9,5
Carbon black n324 40,0 40,0 40,0 40,0
Silicon carbide - - - -
Perlite - 10,0 15,0 20,0
Kinetic parameters of rubber compounds were determined using a rheometer MDR 3000 Professional.
Results and Discussion
When introduced into the rubber compound microfine silicon carbide, an optimal combination of rheological parameters observed in the composition of 3 - the content of carbon black and silicon carbide to 20 parts by weight 100 parts rubber (Table 2). With such a combination of carbon black and silicon carbide is achieved increase the cure rate while increasing the induction period. Increasing the content of silicon carbide leads to faster curing that can be caused by the catalytic action of silicon carbide.
Table 2 - The cure characteristics of rubber compounds*
In case of introduction of perlite also increase the induction period is observed, but the cure rate is practically unchanged.
With simultaneous introduction of the composition of carbon black and microfine silicon carbide or perlite reached an acceptable level of physical and mechanical properties (Table 3).
This allows the use of silicon carbide and perlite to reduce the cost of rubber.
To estimate the heat resistance, the dependence of the temperature on the unexposed surface of the sample from the exposure time of the plasmotron flame was determined. Temperature on the sample surface was about 2500°C.
When exposed to flame on the control sample is practically not formed "coke cap" (Fig. 1a), while samples containing silicon carbide and pearlite (Fig. 1b, c) on the surface of formed a dense and resistant to fire coke, protecting the sample from burning.
Table 3 - Physical and mechanical properties of vulcanizates*
Parameter Control С1 С2 С3
Tensile strength /), MPa 10,2 11,1 6,3 4,5
Elongation at break (sOTH), % 560 637 417 310
Relative residual Elongation after break (0OCT), % 21 8 8 4
Hardness, Shore A 59 45 50 51
Density, g/cm3 1,06 1,13 1,10 1,08
Linear combustion velocity, mm/min 24,45 15,50 13,90 14,30
Warm-up time of the sample surface to 100 °C, sec 119 120 130 150
Change of parameters after aging (100 0C x 72 hrs.),%:
- A/p -38 -23 +16 +13
- Ae -60 -43 -32 -35
Parameter Control П1 П2 П3
Tensile strength /), MPa 10,2 11,1 10,8 8,8
Elongation at break (eOTH), % 560 476 490 453
Relative residual Elongation after break (0OCT), % 21 16 13 20
Hardness, Shore A 59 60 61 60
Density, g/cm3 1,06 1,08 1,06 1,05
Linear combustion velocity, mm/min 24,45 22,86 18,38 20,64
Warm-up time of the sample surface to 100 °C, sec 119 172 189 202
Change of parameters after aging (100 0C x 72 hrs.),%:
- A/p -38 -37 -35 -38
- Ae -60 -57 -48 -50
Mode of vulcanization 155 оС х 40 min
Parameter Control С1 С2 С3
Minimal torque (Mmm), N-m 1,23 1,46 1,25 1,32
Maximal torque (Mmax), N-m 9,24 7,39 9,20 9,41
Starting time of vulcanization (ts), 2,83 3,31 3,31 4,02
min
The optimum cure time (t90), min 31,00 31,89 26,93 26,46
Cure rate index (Rv), min"1 3,55 3,59 4,23 4,32
Parameter Control П1 П2 П3
Minimal torque (Mmin), N-m 1,23 1,30 1,23 1,95
Maximal torque (Mmax), N-m 9,24 9,17 9,86 11,78
Starting time of vulcanization (ts), 2,83 3,54 3,54 4,02
min
The optimum cure time (t90), min 31,00 31,00 29,50 35,91
Cure rate index (Rv), min"1 3,55 3,51 3,85 3,14
The temperature of vulcanization 155°C
c)
Fig. 1 - Changes in the structure of the sample, after exposure to flame: a) control; b) silicon carbide; c) perlite
b)
protects the rubber from burning under the action of fire. Plate-shaped silicon carbide particles allows to create kind of barrier layer protecting sample from exposure to flames.
So, the research has shown that silicon carbide and pearlite can be used to effectively enhance the fire resistance of elastomeric materials and reduce their cost.
The work has been done with support of project "Development of modifiers and functional fillers for fire and heat protective polymer materials" which was carried out within the government contract with Russian Ministry of Education.
References
1. Zaikov G.E. Burning, degradation and stabilization of polymers / Ed. GE Zaikova - St. Petersburg: Scientific bases of technology, 2008 - 420 p.
2. Investigation of rubber with microdispersed wastes of silicon carbide / Lifanov V.S., Kablov V.F., Lapin S.V., Kochetkov V.G., Novopoltseva O.M., Zaikov G.E. // High Performance Elastomer Materials. An Engineering Approach / ed. by D.M. Bielinski, R. Kozlowski, G.E. Zaikov. - Toronto ; New Jersey : Apple Academic Press, 2014. - P. 109-117.
3. Influence of transition metal compounds on fire and heat resistance of rubber mixtures / Kablov V.F., Kochetkov V.G., Novopoltseva O.M., Kostenko N.V., Kalinova K.A., Zaikov G.E. // Вестник Казанского технологического унта. - 2014. - Т. 17, № 8. - C. 134-135.
4. 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
5. 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
6. Lifanov V.S., Kablov V.F., Lapin S.V., Kochetkov V.G., Novopoltseva O.M. Elastomeric materials with microdispersed silica carbide wastes// Kauchukirezina, 2013. №6, pp. 8-10.
7. Investigation of the effect of transition metal compounds on fire and heatresistance of elastomeric compositions / Kablov V.F., Novopoltseva O.M., Kochetkov V.G., A.V. Lapina // News VSTU. A series of "Chemistry and Technology of Organoelement monomers and polymers." Vol. 13: Hi. Sat. scientific. Art. / VSTU. - Volgograd, 2014. - № 22 (149). - C. 68-71.
8. Investigation of heat-shielding polymeric materials containing functional fillers / Kablov V.F., Novopoltseva O.M., Kochetkov V.G., Kostenko N.V. // News VSTU. A series of "Chemistry and Technology of Organoelement monomers and polymers." Vol. 13: Hi. Sat. scientific. Art. / VSTU. - Volgograd, 2014. - № 22 (149). - C. 65-68.
Fig. 2 - Appearance of the coke surface under the action of flame : a) silicon carbide; b) perlite
Microplates silicon carbide on the surface of the coke can be seen in Fig. 2. Because silicon carbide highly thermal resistance and resistant to oxidation material, so the silicon carbide barrier layer effectively
© V. F. Kablov — Doctor of Engineering, Full Professor, Director, Head of Department, Volzhsky Polytechnical Institute (branch) VSTU, Volzhsky, Russia, O.M. Novopoltseva - Doctor of Engineering, Full Professor, VSTU, nov@volpi.ru, V. G. Kochetkov — Post-Graduate Student, VSTU, N. V. Kostenko - Student, VSTU, A. G. Lapina - Student, VSTU, V. S. Lifanov - Post-Graduate Student, VSTU, G. E. Zaikov - Doctor of Chemistry, Full Professor, Plastics Technology Department, KNRTU, Kazan, Russia, Kh.S. Abzaldinov - Ph.D., Associate Professor, Plastics Technology Department, KNRTU, Kazan, Russia.
© В. Ф. Каблов - д-р техн. наук, проф., дир., зав. каф., Волжский политехнический институт (филиал) ВГТУ, О. М. Новопольцева - д-р техн. наук, проф., ВГТУ, nov@volpi.ru, В.Г. Кочетков - асп., ВГТУ, Н. В. Костенко - студент, ВГТУ, А. Г. Лапина - студент, ВГТУ, В. С. Лифанов - аспирант, ВГТУ, Г.Е. Заиков — д-р техн. наук, проф., каф. технологии пластических масс КНИТУ; Х. С. Абзальдинов -канд. хим. наук, доцент той же кафедры.
