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Section 10. Chemistry
Section 10. Chemistry Секция 10. Химия
Ahmedov Aladdin Islam ogli, Azerbaijan National Academy of Sciences Academician A. M. Guliyev Institute of Chemistry of Additives, doctor of technical Sciences, professor E-mail: aki0S@mail.ru Hamidova Jeyhun Shafayat gizi, Azerbaijan National Academy of Sciences Academician A. M. Guliyev Institute of Chemistry of Additives, PhD in Chemistry, associate professor, E-mail: c.hamidova@mail.ru Isakov Elxan Urshan ogli, Azerbaijan National Academy of Sciences Academician A. M. Guliyev Institute of Chemistry of Additives, PhD in Chemistry, associate professor E-mail: vmsh_14@mail.ru Hasanova Elnara Ismatgizi, Azerbaijan National Academy of Sciences Academician A. M. Guliyev Institute of Chemistry
of Additives, PhD in Chemistry E-mail: amea.elnara@mail.ru
Synthesis of copolymers of decylmethacrylate with 4-methylpentene-1 as a viscosity additive
Abstract: The results of synthesis of copolymers of decylmethacrylate with 4-methylpentene-1 by method radical polymerization in the presence of the initiator are given in this article. The synthesized copolymers were studied as viscosity additives for petroleum oils.
Key words: decylmethacrylate, 4-methylpentene-1, coopolymerizatation, viscosity additives, thermal stability.
Lubricating oils have a composite structure, and contain various additives of functional action. Among these polymer additives occupy a special position, as additives, along with other performance characteristics improve the viscosity-temperature characteristics of lubricants, i. e. increases the viscosity index. If base oil
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on viscosity index value does not meet the requirements, then on the basis thereof a lubricant composition is not developed [1, 139].
In order to improve the viscosity-temperature features of oil, the viscosity additives, synthetic components for petroleum oils, blending them with synthetic oils are used.
Viscosity additives, relative high polymers or copolymers of vinyl monomers (M = 8000-12000) are used in concentrations of up to 3%, and economically very beneficial. However, during operation they are subject to degradation and viscosity of oil thickened by them drops below the minimum rate, which leads to premature failure of the machinery.
Synthetic components, a relatively low molecular weight oligomers of a- olefins (M= 3000-5000) are used at a concentration of 20-30%, and very resistant to disruptive influences. However, the way to improve the viscosity-temperature properties of petroleum oils is not economically profitable.
Finally, the use ofa synthetic oil composed of mineral oils. This way is forced, because, in some cases, petroleum oils, despite the presence of the most effective additives in them do not satisfy the increasing demands ofmodern technology. In such cases, semi-synthetic or partially synthetic oils are used for the development of lubricating compositions.
In our opinion, a more simple and cost-effective way to obtain oils with good viscosity — temperature characteristics is the use of viscosity additives that are highly resistant to the destructive influences, i. e. development of more advanced viscosity additives.
Among the known viscosity additives polyalkylmethacrylates have advantages before the hydrocarbon polymers — they are obtained by a more ecological technologies (by free radical polymerization), and they are irreplaceable to improve the viscosity-temperature, especially the low-temperature properties of petroleum oils [2, 36-52].
Based on the above, studies have been conducted on the synthesis of viscosity additives copolymerization Decylmethacrylate with 4-methylpentene-1.
Decylmethacrylate was prepared in the laboratory by reacting methacrylic acid and decyl alcohol.
4-methylpentene -1 some kind of dimer propylene:
CH2 CH + CH2^CH ----------------*~CH2^CH-----------CH2-----CH—CH3
CH3 CH3 CH3
Both monomers are used in the copolymerization in freshly distilled state. This copolymer was synthesized buy us for the first time.
Copolymerization of these monomer pairs is conducted by radical polymerization in the presence of an initiator — benzoic peroxide. The influence of various factors on the results of the process (Table1) has been studied.
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Table 1. - Copolymerization decylmethacrylate with 4-methylpentene-1
Copolymerization conditions Copolymer characteristics
Decylmethacrylate: 4-methylpentene -1,% Т, 0 С Initiator consumption,% Output,% Molecular weight
90: 10 60 0,7 92,5 12000
90: 10 70 0,7 92,8 11000
90: 10 80 0,7 92,8 10000
80: 20 70 0,7 84,3 9000
70: 30 70 0,7 76,9 7000
90:10 70 0,3 65,4 13000
90: 10 70 0,5 72,4 12000
As seen from Table 1, the temperature increase in the range of 60-80 0C results in a lower molecular weight of 12000 to 10000. This is because the temperature rise accelerates all reactions, including reactions that lead to the cessation of growth of the polymer chain. At that the output varies slightly.
Increase of composition of 4-methylpentene-1 in the initial monomer mixture reduces both the output and molecular weight of the copolymers. As it is known, a-olefins are not polymerized by a radical mechanism, therefore their involvement in the copolymerization on radical mechanism for inhibitory effect on the process.
Reduction ofconsumption of initiator ofless than 0.7% ofa mixture ofmonomers is purposeful, so at that a reduction in output of the copolymer occurs.
The composition and structure of the synthesized copolymers are studied by methods of elemental analysis and spectroscopy. The formation of a mixture of decylmethacrylate homopolymer with the copolymer of decylmethacrylate with 4-methylpentene-1 was established. On the basis of these studies the following general formula for the copolymer is suggested:
CH
CH2—C
CH2 CH
COOC10H21
CH2CH(CH3)2
m
Where n = 3-40; m = 5-70
The synthesized copolymers were studied as viscosity additives for petroleum oils. First their effect on viscosity-temperature characteristics of less viscous industrial oil И-12А is studied.
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И-12Л oil was solidified to a viscosity level 8±0,5 mm 2/s. For comparison polydecylmethacrylate and industrial viscous additive Viscoplex of brand V-2-670 were used. The results of these studies are shown in Table 2.
As can be seen from the data presented in Table 2, the increase in the composition of a- olefin units in the copolymer significantly affects the viscosity-temperature properties of solidified oils; a slight deterioration in viscosity- temperature properties occurs: viscosity index decreases from 140 to 134, the kinematic viscosity at minus 18 °C increases from 1300 to 1400, due relatively short substituent in the molecule of 4-methylpentene-1 as compared to decylmethacrylate.
Table 2. - Affect of copolymers decylmethacrilate with 4-metylpentene (4-MP-1) on viscosity-temperature characteristics of oil И -12Л
Characteristics of solidified oil
Number of chains of 4-MP-1 in copolymer,% Kinematic viscosity at 100 0 С, mm 2/s Viscosity Index Kinematic viscosity, mm 2/s, at minus 18 0 С
0 8,2 140 1300
(polydecylmethacrylate) 5 7,9 136 1320
10 8,00 134 1350
15 8,10 134 1350
20 8,20 134 1400
25 8,06 134 1400
V-2-670 7,30 126 1400
However, these values obtained are within the permissible norms on GOST (State Standard) 17.479.1-85. Solidified oils with viscosity at 100o C should have a viscosity index not leas than 125 and a kinematic viscosity at minus 18 °C not more than 2600 mm 2/s.
The next step in study of the influence of the synthesized copolymers on the viscosity- temperature properties of solidified by them oil И-12Л was to study the effect of molecular weight values to the specified index. The results of these studies are shown in Table 3.
As can be seen from Table 3 И-12Л oil is solidified with copolymers of different molecular weights to the same level of viscosity about ~ 8 mm 2/s. Regardless of the molecular weight of the copolymer used to thicken the И-12Л oil, viscosity-temperature properties of the base oils are within normal range.
However, it should be noted that with the reduction of molecular weight of the copolymer its consumption to solidify to achieve the desired kinematic viscosity at 100o C increases.
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Section 10. Chemistry
Table 3. - The influence of the values of the molecular weight of the copolymer on the viscosity-temperature characteristics of the oil И-12Л
Characteristics
Copolymer Solidified oil
Molecular weight Concentration, % Viscosity, mm 2/s at temperature, оС Viscosity Index
100 minus 18
7000 10,0 8,0 1700 130
9000 8,6 7,9 1650 134
11000 7,8 8,1 1500 136
13000 6,0 7,9 1400 138
15000 5,1 8,0 1300 140
Therefore, the composition and molecular weight of the copolymer used as the viscosity additives is determined from the specific requirements for the quality of the developed solidified oil.
Another important indicator of viscosity additives is their resistance to thermal shocks. There are various methods for determining the thermal stability of the polymer compounds. With respect to viscosity additives more effective additives are a common method [1], the essence of which is in heating of 5% solutions of the samples in the turbine oil “L” at 200°C for 12 hours. During testing at intervals the reduction of viscosity (r. v.) is determined according to the following formula:
v — v
r .v. = —--- 100%v
vuu
Where vu - Initial kinematic viscosity of solidified oil
vk - The same after the test
The results of the study of the thermal stability of the copolymers decylmethacrylate - 4-methylpentene-1 are shown in Table 4.
As can be seen from Table 4, the increase of molecular weight of copolymers within 1000-14000 limits reduces their thermal stability, reducing the viscosity of oil thickened by degradation increases from 2.1 to 4.8%. So, macromolecules affect their behaviour during heat exposure - a relatively high molecular weight samples hardly move without breaking the chemical backbone.
Increase of composition of units of 4-methylpentene-1 in the copolymer leads to an increase in stability of solidified oils - reducing the viscosity drops from 4.8 to 2.6%. So a a-olefin unit in the polyalkylmethacrylate chain has a stabilizing effect on the copolymer. This is due, firstly, formation of new connections during copolymerization (chemical modification), i. e. copolymerization is a method of directional changes in physical and mechanical properties of polymeric compounds. Second, poly-a-olefin
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polymers are characterized by a higher resistance to the destructive effects than polyalkylmethacrylates.
Table 4. - Results of thermal degradation of copolymers decylmethacrylate 4-methylpentene-1 (4-MP-1) in the oil
Copolymers characteristics Reduction of viscosity%, due to destruction at duration of tests, hours
Molecular weight Composition of chain of 4-MP-1 in copolymers,% 1 4 8 12
10000 10 0,4 0,8 1,3 2,1
12000 10 0,6 1,9 2,3 3,0
14000 10 1,8 2,0 3,4 4,8
14000 20 0,4 1,5 2,2 2,9
14000 30 0,4 1,4 2,0 2,6
Therefore the introduction of units of a-olefin in the polymer chain increases the thermal stability of the samples tested.
By changing the molecular weight of the synthesized copolymers and their composition their thermal stability can be regulated in order to obtain the desired results.
Thus, summarizing the results of the research, it can be concluded that by copolymerization of decylmethacrylates with 4-methylpentene-1 polymer compounds were obtained, which when examined as viscosity additives meet modern requirements. In this direction, the Institute of Chemistry ofAdditives of the National Academy of Sciences of Azerbaijan conducts extensive studies. The material presented here is a special case of the studies conducted.
References
1. Кулиев A. M. Химия и технология топлив и масел. - Л.: Химия, 1885.
2. Ахмедов А. И., Фарзалиев В. М., Алигулиев Р. М. Полимерные присадки и масла. - Баку: Элм, 2000.
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