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AZERBAIJAN CHEMICAL JOURNAL № 1 2019
19
UDC 678.742.4-136.23.01:678.023
VULCANIZATION OF BUTYL RUBBER IN THE PRESENCE OF 2-(2-OXA-6-THIADECYL)OXIRANE
O.B.Abdiyev, B.A.Mamedov, *E.G.Mamedbeyli, A.M.Garamanov, N.Kh.Gusiyev
Institute of Polymer Materials, NAS of Azerbaijan Yu.GMamedaliyev Institute of Petrochemical Processes, NAS of Azerbaijan
ipoma@science.az
Received 22.06.2018
The vulcanization of rubber mixture of butyl rubber containing ether- or thioether-containing oxirane in its composition and physico-mechanical properties of the prepared vulcanizate have been determined. It has been revealed that its endurance in multiple stretching is higher than for vulcanizate prepared from rubber mixture not containing above-mentioned oxirane.
Keywords: vulcanization, butyl rubber, ingredient, 2-(2-oxa-6-thiadesil)oxirane, epichlorohydrin. https://doi.org/10.32737/0005-2531-2019-1-19-22
The rubbers on the basis of butyl rubber possess high heat- and ozone resistance, gas impermeability, resistance to aggressive media and swelling in the water, high dielectric properties. However, along with these positive properties, these rubbers possess also negative characteristics - low endurance at multiple stretching. Now there are scientific works devoted to elimination of this lack by application of new rubber mixtures. For example, it was carried out the sulphur vulcanization of rubber mixture of butyl rubber having ingredient mixture of glycidyl-1-methoxy-1 -cyclopentanecarboxylate (GMCPC) [1]. The rubbers prepared by vulcanization of this mixture had also this lack. The investigations of other authors [2-6] also did not bring tangible positive results.
The solution of this problem requires the carrying out of investigations with application of various classes of the compounds with strictly determined structure as an addition.
Taking into account above-mentioned one, this paper has been devoted to the preparation of vulcanizate on the basis of butyl rubber by vulcanization of the rubber mixture containing 2-(2-oxy-6-thiadecyl)oxirane (OTDO), sulphur and butyl rubber and also to the study of structure of OTDO.
Experimental part
For carrying out of vulcanization of butyl rubber in the presence of OTDO there have been made the rubber mixtures, a composition of which has been presented in Table 1. In Table the data of quantitative data of GMCPC,
taken from literature [1] with the aim of comparison of the physico-mechanical parameters of vulcanizates prepared in the presence of GMCPC with physical-mechanical parameters of vulcanizates prepared in the presence of OTDO and GMCPC have been also presented.
The vulcanization was carried out by pressing for 20, 40 and 60 min at temperature 1430C.
OTDO has been prepared by interaction of 4-thia-1-octanol (TO) with epichlorohydrin (ECH). TO was synthesized by addition of n-butyl mercaptane to 2-propen-1-ol on methodology [8]. Bp. - 105-1060C/0.5 kPa, df =
0.9660, n^0 = 1.4832.
Preparation of OTDO. The mixture 23 g (0.2 mol) of TO, 12.43 g (0.31 mol) of NaOH, 21.5 g (0.23 mol) of epichlorohydrin and 140 ml of toluene was heated at 850C for 3 h. After neutralization, drying, filtration of organic layer, toluene sublimation and residue distillation it has been prepared 25.5 g (57%) of OTDO. B.p. -1120C/0.2 kPa, < = 1.4740, d420 = 0.9957. Found, %: C 59.03, H 10.16, S 15.97. C12H16O2S. Calculated, %: C 58.78, H 9.87, S 15.69.
OTDO, TO used at synthesis can consist of mixture of two isomers: 4-thia-1-octanol and 3-thia-1-heptanol. The prepared product should also consist of two similar isomers: OTDO (forming from 4-thia-1-octanol and ECH) and 2-oxa-5-thia-4-methylnonanyl oxirane (OTMNO) (forming from 4-thia-1-octanol and ECH).
Table 1. Optimal composition of mixture of ingredients in mass part (m.p.) for preparation of vulcanízate of butyl rubber
Composition of rubber mixture Known mixtures Suggested mixtures (samples), having OTDO in the composition
quantity of ingredients in mixture, not containing OTDO and GMCPC [1] quantity of ingredients in mixture, containing GMCPC [2] example 1 example 2 example 3
Butyl rubber of mark 2045 100 100 100 100 100
Steraic acid 3.0 3.0 3.0 3.0 3.0
Captax 0.65 0.65 0.65 0.65 0.65
Thiuram 1.3 1.3 1.3 1.3 1.3
Zinc oxide 5.0 5.0 5.0 5.0 5.0
Carbon black DG-100 50 50 50 50 50
Sulphur 1.5 2.0 2.0 2.0 2.0
GMCPC - 3.0 - - -
OTDO - - 1.0 3.0 8.0
The determination whether the product consists only of OTDO or OTMNO or from mixture of these isomers, makes it possible to accurately determine the physico-mechanical properties of the rubber prepared after vulcanization. The structure of the synthesized product has been investigated by spectroscopic methods, GLC and elemental analysis.
In the IR spectrum of the prepared product there are frequencies 3060, 1255, 850, 920 cm-1, characteristic for C-S-C group. There have been also found the bands at 1120, 1240 and 1375 cm-1, characteristic for ether bond, oxirane and methyl groups, respectively. The intensive bands at 2874-2961, 1485 cm-1 belong to -CH2-C,
I I
CH— (—CH— is in oxirane ring) groups.
In the spectrum 1H NMR there are appeared the following signals of protons (CD3COCD3, 5, ppm): 0.84 s (3H, CH3-C-C-), 1.2-1.89 m (6H, -CH2CH2-C-S-, -CH2-),
2.47d (2H, ^C—CH2 ), 2.63 q (4H, -CH2-S-CH2-), 3.41-3.72 m (5H, CH2-O-CH2-,
2 CH ). An absence of duplicate at 2.86 ppm
S—CH
belonging to -CH- proton in fragment I ,
CH3
and also an appearance of only one peak belonging to OTDO in GLC (Figure) shows that as a result of reaction only OTDO was prepared.
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a «
и
о
dn
Time, mill
Chromatogram of OTDO (column lK = 3m; 10% apiezone on zeolite 545; t = 2000C; Jdet. = 100 mA, gas-bearer rate (helium) - 37 ml/min).
Results and discussion
With the aim of elucidation of dependence of the physico-mechanical parameters values on nature and composition of 2-(2-oxa-6-thia-decyl)oxirane there has been carried out the vulcanization of rubber mixture containing above-mentioned oxiranyl sulphide and without it. In the literature [1] the physico-mechanical parameters of rubber prepared from rubber mixture of the similar composition, but with the participation of GMCPC have been taken (Table 2).
O.B.ABDIYEV et al. 21
Table 2. Physico-mechamcal parameters of rubbers prepared by vulcanization of rubber mixture of butyl rubber
Parameters Known rubbers Rubbers having OTDO in the composition (samples)
rubber, not containing OTDO and GMCPC rubber, containing GMCPC example 1 example 2 example 3
Vulcanization time, min 40 20 40 40 40
Modulus at 300% elongation, MPa 8.0 8.1 8.4 8.2 7.8
Modulus at 400% elongation, MPa 11.5 10.8 11.2 11.0 9.3
Breaking resistance, kgs/cm2 22.0 24.0 23.5 26.2 22.5
Specific elongation, % 600 650 700 730 760
Residual elongation, % 36 28 32 36 50
Hardness on TM-2 64 58 56 58 54
Rebound elasticity, % at 200C 8.0 9.0 10.0 10.0 11.5
Endurance at multiple stretching (500 cycle/min), min-1 67.5 114.13 120.39 196.5 142.43
Mooney viscosity at 1200C - - 51 48 45
Time to beginning of prevulcaniza-tion at 120°C, min - - 23.5 20.0 18.2
In passing from one experiment to another one a quantity of oxiranyl sulphide was changed as shown in Table 1, and a quantity of the remaining ingredients was kept mainly constant. The carrying out the investigations in this style creates a possibility to reveal the causes of changes of the obtained results.
It is seen from Table 2 that the rubbers forming from mixtures of ingredients containing OTDO have higher endurance in multiple stretching (EMS) than the rubbers not containing OTDO in the composition. In addition, the rubber containing GMCPC shows also the higher EMS value than the rubber of butyl rubber not containing OTDO. This index is also differed in rubbers containing OTDO and GMCPC in ingredient mixture. In the first case (example 1) its value is higher than in the second case (example 2). It is also seen that with increase of a quantity of OTDO from 1 to 3 m.p., in the mixture EMS value of rubber increases from 120.39 to 196.5 cycles/min. Further increase of a quantity of OTDO up to 8 m.p., leads to a decrease of EMS to 142.43. These results can be explained by the fact that, as shown in [8], during vulcanization, owing to availability of epoxide compound in the rubber mixture, due to interaction of epoxide ring with labile rubber atoms, its structuring can be activated and, consequently - increase of its some physico-mechanical properties, including EMS.
If one agree with this assumption, the rubber prepared from mixture of ingredients containing GMCPC, having in molecules such
groups, as oxirane, carboxyl and ether helping increase of EMS by structuring during its preparation by vulcanization should have EMS value higher than the rubber containing OTDO, having only oxirane and ether group in the molecule, helping structuring, in the composition of ingredient mixture. However, the results of experiments showed the reverse result and, consequently, this assumption cannot be accepted.
The obtained data can be explained, taking into account the fact that in addition of above-mentioned one, the finding factor of sulphide group C-S-C in the composition of OTDO influences on the vulcanization process. Due to this, it better dissolves the sulphur (incoming in composition of ingredients of a mixture) than GMCPC. Especially, it has been shown in work [9] that some compounds, dissolving such sulphur, convert the vulcanization mixtures to homogeneous ones.
Under this condition, at rubber vulcanization, the particles of the ingredients are permitted to interact with each other to an even greater degree, than in the absence of OTDO in the composition of ingredients. Finally, it is prepared the rubber having higher EMS values than the rubbers not having OTDO in the composition of ingredients or containing GMCPC.
The above-mentioned decrease of EMS value in increase of a quantity of OTDO in the ingredient mixture to 8 m.p., can be explained by increase of softness of the rubber and consequently, by decrease of its physico-mechanical properties, including EMS.
Conclusions
1. It has been shown that at vulcanization of butyl rubber in the presence of OTDO the prepared rubber has a higher endurance value in multiple stretching in comparison with rubbers prepared in the presence of GMCPC and without participation of OTDO and GMCPC.
2. It has been revealed that the vulcanization of butyl rubber in the presence of OTDO leads to a preparation of rubber having a great endurance value in multiple stretching than the rubber prepared in the presence of GMCPC.
3. It has been detected that at vulcanization of butyl rubber having OTDO in the ingredient mixture with increase of a quantity of OTDO in the mixture from 1 to 3 m.p. EMS value of the rubber is increased from 120.39 to 196.5 min-1. The further increase of a quantity of OTDO to 8 m.p., leads to a decrease of this index to 142.43 min-1.
4. It has been established that at synthesis of OTDO by interaction of ECH with 4-thia-1-octanol (addition product of butyl mer-captane to 2-propen-1-ol) instead of the expected mixture of isomers of OTDO and OTMNO it is prepared an individual OTDO.
References
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3. Vagizova R.R., Hakimualin Iu.N., Stepanov P.A., Bylev V.A. Svoistva i struktura rezin na osnove butilkauchuka i ego radiatcionnogo regenerata // XIII Vserossiiskaia konf. "Struktura i dinamika molekuliarnykh sistem". Ch. 1. Ufa. IFMK UNTC RAN. 2006. S. 155-159.
4. Markov V.V., Monahova T.V., Popov A.A., Reznichenko S.A. Vliianie polietilena na kineti-ku okisleniia kislorodom syrykh rezinovykh smesei na osnove butilkauchuka i etilenpro-pilendieno-vogo kauchuka // Tezisy docl. IV Vseross. nauchn. konf. "Fizikohimiia protcessov pererabotki poli-merov". Ivanovo. 2009. S. 87.
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8. Mamedov Sh.M. Osnovy tekhnologii sinteza, pererabotki i vulkanizatcii butadiennitrilnykh kauchukov. Baku: AGNA. 2013. 322 s.
9. §ixaliyev K. Rezin texnologiyasi. Baki: Maarif n9§riyyati. 1979. 264 s.
2-(2-OKSA-6-TiADESiL)OKSiRAN i§TiRAKI iLЭ BUTiLKAUCUKUN VULKANLA§DIRILMASI
O.B.Abdlyev, B.A.Mэmmэdov, E.H.MэmmэdbэyH, A.M.Qaramanov, H.X.Hйsiyev
ТэгЫЫМэ sadэ eflr, tioeflr qruplan о1ап 2(2-oksa-6-tiadesil)oksiran i§tirakl Иэ butilkauдakun vulkanla§dlnlmasl Ьэуа1а кедпЛт^ш А1тап rezlnin fizlkl-mexamki kэmiyyэt1эrlnin qlymэt1эrl tэyln edilmi§dir Gбstэrilmi§dir Ы, Иэшт шэИ8и1ип dэfэ1эr1э dartllmaya qar§l davamllllgl kauдukun бzйndэn акпап rezlnin davamllllgшa nisbэtэn дох yйksэkdlr.
Адаг sдzlэri: vulkanla§ma, ЬШШащЛ, inqredient, 2-(2-oкsa-б-tiadesil)oкsiran,epixlorhidrin.
ВУЛКАНИЗАЦИЯ БУТИЛОВОГО КАУЧУКА В ПРИСУТСТВИИ 2-(2-ОКСА-6-
TИДДЕЦИЛ)ОКСИРАНА
О.Б.Абдыев, Б.А.Мамедов, Э.Г.Мамедбейли, А.М.Гараманов, Н.Х.Гусиев
Исследована вулканизация резиновой смеси бутилкаучука, содержащего в составе эфир- или тиоэфирсодержа-щий оксиран, и определены физико-механические свойства полученного вулканизата. Выявлено, что его выносливость при многократном растяжении выше, чем у вулканизата, полученного из резиновой смеси бутилка-учука, не содержащего вышеуказанный оксиран.
Ключевые слова: вулканизация, бутилкаучук, ингредиент, 2-(2-окса-б-тиадецил)оксиран, эпихлоргидрин.
