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Urinov Ulugbek Komiljonovish, associate professor Tashkent chemical-technological institute Maksumova Oytura Sitdikovna, Doktor of Chemistry, professor Tashkent chemical-technological institute E-mail: omaksumovas@mail.ru
COPOLYMERIZATION OF ACRILONITRILE WITH DIFFICULT ETHERS (MET)ACRYLIC ASIDS
Abstract. This article presents the results of the study of fiber-forming copolymers based on N-morpholine-3-chloroisopropyl acrylate and isohexyl methacrylic ester with acrylonitrile. Keywords: copolymer, unsaturated esters, acrylonitrile, radical polymerization, initiator.
Introduction
Chemical, textile, aircraft and mechanical engineering and a number of other industries are in dire need of structural materials based on carbon fibers, one of which is polyacrylonitrile fibers. The mechanical properties of PAN fibers are very close to wool, and in this respect they are superior to all other chemical fibers. Polyacrylonitrile fibers have a good range of consumer properties. Polyacrylonitrile fibers, in particular nitrone, attracts the attention of many researchers due to their availability. They are often called "artificial wool". They have maximum light resistance, high strength and relatively high tensile properties (22-35%). The disadvantages of polyacrylonitrile (PAN) fibers are their
low hygroscopicity, relatively high rigidity and electrification [1, 19-22; 2, 26-30].
Findings and their discussion
It is known that an effective method of imparting specific properties to chemical fibers is an includation modification carried out in the process of their production. In this regard, we were interested in the synthesis ofbinary fiber-forming copolymers on the bases of acrylonitrile with heterofunctional compounds. As the nitrogen and oxygen-containing reagent selected unsaturated ester - N-morpholine-3-chloroisopro-pylacrylate (MHIPA) [3, 88]. Its synthesis was carried out according to the following reaction: and as the oxygen-containing isohexyl methacrylic ester (IH-MEA) [4, 260-261]. The scheme of its formation was carried out according to the following scheme:
ch2
o
h+
ch2=c—ch2—ch2—ch
I
ch2
■2"
12-
13 +
ch2=c—c.
CH3 oh
h3c—c 3 I c=o I
0
1
ch3—c—ch2—ch2—ch3 ch3
The structure of the obtained compounds was determined by IR-spectral analysis (table 1). Table 1. Results of IR-spectr of the synthesized connections
№ Name of compound IR-spectrum
C=C c=o c-o-c
1. MHIPA 1642 1728 1297
2. IHMEA 1636 1730 1280
The copolymerization of acrylonitrile with N-morpholine-3-chloroisopropyl-acrylate and iso-hexylmethacrylic ester was carried out in organic solvents in the presence of dinitrilazobisisobutyric acid initiator (DAK). In the technology ofproducing nitron fibers, aprotic solvents are most widely used: dimethylformamide, dimethylacetamide, dimethyl sulfoxide, 51.5% aqueous solution of NaSCN. However, dimethylformamide and dimethylsulfoxide are the most promising solvents in the copolymerization
of acrylonitrile, since they are the most accessible and less toxic in comparison with aqueous solutions ofso-dium thiocyanate. In this regard, dimethylformamide and dimethyl sulfoxide are chosen as the solvent.
The copolymerization of acrylonitrile with the above comonomers was investigated by the gravimetric method at temperatures of 50-70 °C. The influence of the duration of the copolymerization reaction on the yield of the resulting copolymer was studied (fig. 1).
100-
20
40
60
80 100
120 140
t, i èi
Figurel. Dependence of the yield of copolymer based on acrylonitrile with isohexyl methacrylate ether at a ratio of: 1-0.97: 0.03; 2-0.95: 0.05 mole fraction, T = 60 °C; DMSO solvent
As can be seen from the figure, with a ratio of acrylonitrile: IHMEA equal to 0.97:0.03, the highest reaction rate is observed.
In studies, the duration of the polymerization process was changed (60, 120, 150, 180 min.) and the composition of the copolymer - AN: MHIPA and AN: IHMEA = 0.95: 0.05; 0.97: 0.03 mole fraction (table 2).
The samples were obtained in the form of films by dissolving the copolymer in dimethylformamide, followed by casting. Analysis of the results showed that the optimum polymerization time is 150 minutes. During this period, when the content in the reaction mass was 0.03 mole fraction of the indicated esters, the copolymer yield was 95-97%. It was experimentally established that radical polymerization
p,
of acrylonitrile with N-morpholin-3-chloroisopro- at high speed in the presence of DAA in dimethyl pyl acrylate and isohexylmethacrylic ether proceeds sulfoxide condition.
Table 2. Dependence of the composition of acrylonitrile copolymers on the ratio of monomers in the initial mixture. DAK = 5 • 10-2 mole/l, T = 60 oC, DMFA
The initial ratio of monomers, mole fraction Yield,% Composition of copolymer, mole fraction
М1 М2 m1 m2
AN: IHMEA
G.95 G.G5 97.G G.S6 G.14
G.97 G^ S6.G G.9G G.1G
AN: MHIPA
G.95 G.G5 9S.5 G.S1 G.19
G.97 G^ 97.G G.SS G.12
The main parameters of polymerization in solution: temperature, 50-70 °C; duration, h: 2-4. Synthesis of a binary copolymer based on acrylonitrile with isohexyl methacrylate ether proceeds by a chain radical polymerization mechanism in three stages using as the initiator - DAA. The homogeneous copolymerization of acrylonitrile in solution
CH3 CH3 I 3 I 3
H3C—C-N = N-C—CH3 -
3 I I 3
CN CH3
is well described by the general scheme of radical polymerization, which includes the stages of initiation, growth, transfer, and chain termination.
1. The formation of an active radical. At the initiation stage, free radicals are formed in the reaction system, which are capable of adding monomer molecules:
2CH3
CH3
I 3
f * CH3
N2A
2. Chain growth occurs as a result of sequential radical formed at the initiation stage, and then to the addition of monomer molecules first to the primary growing chain:
CH3 CH3 CH3
2CH3—C' + CH2=CH
3 I 2 I CN CN
H3C—C—CH2—HC' + CH3=C
2
CN
I
CN
3-
CO CH3 I I 3 O—C—CH2-I 2
CH3
CH2—CH
3
CH3
CH3
CH3— C— CH2— HC—CH2— C'
CN CN CO CH3
I I 3
O—C— CH2— CH2— CH3 CH3
3. Chain breakage occurs during the bimolecular mechanism and the structure of the copolymer can interaction of macroradicals by the recombination be represented as follows:
CH3 CH3
2CH3—C—CH2— HC—CH2— C' -
M 2 I 2 I
CN CN CO CH3
I I 3
O—C—CH2— CH2— CH3 CH3
CH3 CH3 I 3 I 3 2CH3— C— CH2— HC—CH2— C-CH2
M 2 I M 2
CN CN CO
I
O
The chemical structure of the obtained copolymers is confirmed by the data of IR-spectral analysis. In the IR-spectra of copolymers based on acry-lonitrile with isohexylmethacrylic ether, absorption bands were found in the region of2900-3000 cm-1, which belong to methylene and methyl groups. The characteristic absorption bands of the nitrile groups (CN) are in the region of 2250-2260 cm-1, the stretching vibrations of the ester group in the region of 1100 and 1300 cm-1, and the absorption bands in the region of 1655 cm-1 correspond
CH3 I 3 -C' I
CO
I
o
I I
H3C—C—CH3 H3C—C—CH3
CH2 CH2
I 2 I 2
CH2 CH2
I 2 I 2
CH3 CH3
to the stretching vibrations of the carbonyl group. The absence in the spectra of the absorption bands of double bonds C=C at 1600-1670 cm-1 indicates that the reaction proceeds beyond the opening of the double bonds of both monomers. Conclusion
The radical copolymerization of acrylonitrile with N-morpholine-3-chloroisopropylacrylate and isohexylmethacrylic ester was studied. The influence of the ratio of the initial monomers on the yield of the final product was studied
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3. Maksumova O., Urinov U. Synthesis of Derivatives of morpholinium with acrylic and metakrilovy asids // International conference on thermophysical and mechanical properties of advanced materials, 2014. Izmir, - Turkey.- 88 p.
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