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17
UDC 541.64: 547:512
SYNTHESIS OF AN OPTICALLY TRANSPARENT COPOLYMER ON THE BASIS OF N-
VINYL CARBAZOLE AND STYRENE
12 1 2 1 S.B. Mammadli , F.A. Amirov , A.V. Alamdarlyi , U.B. Orucaliyeva , D.R. Nurullayeva
institute of Polymer Materials of Azerbaijan National Academy of Sciences, AZ 5004 Sumgait, S.Vurgun str., 124, e-mail: seide.mamedli@yandex.ru 2Azerbaijan State University of Oil and Industry, Baku, AZ 1010, Azadlig ave., 20 e-mail: unalaorujaliyeva12@gmail.com
Received 21.09.2022 Accepted 20.11.2022
Abstract: As a result of copolymerization of N-vinyl carbazole with styrene, the optically transparent copolymer was synthesized and the regularities of the copolymerization process, the composition and structure of the copolymer determined. The copolymerization constant values were determined by the Fineman-Ross method (r=0.032, r2=5.5). It found that the styrene shows higher activity than N-vinyl carbazole. The parameters value of the copolymer microstructure was reveled. The obtained copolymer has a sufficiently high light-refractive index (n^0 =1.6504). The light transmission capacity of the copolymer is 87-89%. Varying the initial composition of the copolymer, the influence of the composition on the physical-mechanical properties of the copolymer was determined. It found that with an increase in N-vinyl carbazole links, the thermal stability in the copolymer increased proportionally. It was established that the mass loss of this copolymer at 280°C during thermal degradation was ™5-6 %.
Keywords: N-vinyl carbazole, styrene, copolymerization, microstructure, optically transparent materials DOI: 10.32737/2221-8688-2022-3-3 74-380
Introduction
The opto- and microoptoelectronic devices of the future generation are in need of optically transparent, heat-resistant, as well as electrical-isolating materials [1-4]. This new idea for optical discoveries inspired the researchers to create new optically transparent materials. One of the perspective representatives is the copolymer of N-vinyl carbazole with styrene.
Poly-N-vinyl carbazole (PVC) is a transparent, colorless, amorphous thermoplastic polymer and has sufficiently high light transmission coefficient (n^0 = 1.6830). PVC absorbs light in the UV field of the spectrum, but its photosensitivity extends to X = 1 |im [5, 6]. The large-volume carbazole groups add this polymer a relatively high heat resistance, which is higher than polymethylmethacrylate and polystyrene (PS) (pv = 1013-1015 Omm) [7, 8]. PS has a high degree of optical transparency, excellent dielectric properties [9-12]. At the
same time, the specific weight of PS is low and is easily processed. However, PS is a hard fragile amorphous polymer with low mechanical strength and chemical resistance [13-14].
PS is rarely used in its pure form due to the above-mentioned weak properties. In order to increase the flexibility and heat resistance of PS and decrease its solubility, the styrene is purposefully copolymerized with other monomers. Also, the styrene is modified by monomers with sufficiently optical transparency and high physical-chemical properties [15-18]. As a result, the improved material with a unique set of properties is obtained.
The main purpose of this paper is the preparation of new heat-resistant optically transparent polymer material. For this purpose, the copolymerization of N-vinyl carbazole (VC) with styrene was carried out. The dependence of the composition of the copolymer on the composition of the mixture of monomers was investigated by changing the molar ratio of
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monomers in wide range. The indices of optical transparency and light transmission of the
obtained copolymer were determined.
Results and discussion
Using IR spectral analysis of the copolymer, the availability of the following absorption bands has been shown: 753 cm-1, 696
cm-1 (CH unsubstituted phenylene rings of
carbazole nucleus); 839 cm-1 (C-N aliphatic
nitrocompound), 1598, 1492 cm-1 (benzene nucleus), (Fig. 1). In the IR spectrum of copolymer on the basis of VC and styrene, the valence vibrations of the vinyl bond in the field of 1630-1635 cm-1 are not observed.
Fig. 1. IR spectrum of VC copolymer with styrene.
The link content in the copolymer was established on the nitrogen element in VC. It found that the copolymerization reaction proceeds with the opening of the vinyl group in VC and styrene monomers.
The synthesized copolymer is a white solid substance, which is soluble in benzene, chloroform and carbon tetrachloride.
The structure of VC copolymer with styrene can be presented as follows:
+ n CH2 = CH
—
The copolymerization constants of monomers of VC (M1) and styrene (M2) were established by the Fineman-Ross method (Fig. 2), and the activity coefficients were calculated according to the Alfrey-Price's Q-e scheme (Table 1). The found copolymerization
constants values r1 and r2 (r1<r2) found that M1 monomer shows less activity than M2 monomer in the radical copolymerization, and this difference was due to the chemical nature and activity of molecules in M1 and M2 monomers.
The increase of the quantity of VC in the
initial mixture in the range of 10^90 mol. % leads to the increase of mols% of links of carbazole-type in the composition of copolymers up to ~1.95-44.42 mol.%. At this time, the quantity of N atoms in the composition
of copolymers is naturally increased from 0.3% to 13.65%, and in parallel the quantity of styrene links is decreased from 98.05% to 55.58%.
10
15
20
25
30
F2/f
0
5
0
-2
Fig. 2. The dependence of F/f(f-1) on F2/f for determination of the copolymerization constants
r1 and r2 by the Fineman and Ross method.
Table 1. Conditions of the copolymerization reaction and the quantity of various links (t=70°C,
Initiator - BP)
Quantity of monomers in the initial mixture, mol % Conversion, % Quantity of monomers in the polymer chain, mol % Copolymer r1 r2
M1 M2 m1 m2 N, %
11
10 90 30 69 1.95 98.05 0.3
12
25 75 32 74 12.85 87.14 2.62
50 50 14 36 81 16.88 83.12 4.72 0.032 5.5
20
75 25 43 85 27.85 72.15 10.01
35
90 10 56 92 44.42 55.58 13.65
Qi=0.41, ei=1.40; Q2=1.00, e2=-0.80
In all cases of comonomers conversion, the polymer is soluble. Consequently, in the copolymerization process, the chain transfer to the polymer or structuring processes does not practically occur.
The parameters of the copolymer microstructure were established. It can be seen
from values of the microstructure parameters that the minimal blocking of m2 links is observed in the quantities of -27.85-72.15 mol% and -44.42-55.58 mol%. The high values of the Harwood constant are consistent namely with this interval of capacities in m2 (Table 2).
Table 2. Microstructure parameters of copolymers of VC+St obtained at various initial molar ratios
of monomers
№ Compos initial r mo ition of nixture l.% Composition of copolymers, mol.% Copolymer microstructure
M1 M2 m1 m2 LM1 LM2 R
1 10 90 1.95 98.05 1.003 50.5 3.88
2 25 75 12.85 87.14 1.01 17.5 10.80
3 50 50 16.88 83.12 1.032 6.5 26.55
4 75 25 27.85 72.15 1.096 2.83 50.94
5 90 10 44.42 55.58 1.28 1.61 69.01
LMl and Lm2 - average length of monomer link blocks; R - Harwood's block factor
Changing the ratio of styrene and VC in the initial mixture of monomers, one can vary the composition of the macromolecule and, apparently, the average molecular weight values of the copolymer, and as a result, the glass transitions temperature and the degree of swelling of the copolymer in solvents. As the content of mi fragment in the copolymer increases, the thermal stability of the polymer increases. The increase of a quantity of link of styrene type in the composition of copolymers leads to an increase of the optical transparency values of the copolymers.
The optical transparency of the obtained copolymer was determined on the device Anton Paar Abbemat 200. The given index is equal to n20 = 1.6504. Also, it was established that the light transmission of the copolymer is 87-89%.
The study of the heat-physical properties of a material made from VC copolymer with styrene is an important condition for determination of the areas of its further
application. The heat resistance of this copolymer depends to some extent on its composition. Thus, with an increase of the content of links in the composition of copolymer, the thermal stability of the copolymer increases proportionally. It found that the mass loss of this polymer at 280°C during thermal destruction is ~ 5-6%. The products made from styrene copolymers (about 15%) and vinyl carbazole are notable for high heat resistance. The beginning of deformation of such products under load is observed only at 127°C (instead of 70-75oC for polystyrene products). The advantage of this copolymer over other styrene copolymers is that it maintains the good dielectric properties inherent to PS and PVC.
The obtained polymer has a sufficiently high optical transparency and heat resistance. The obtained polymer can be used in the manufacture of appropriate details of optics, micro- and optoelectronics.
Experimental part
The reaction of radical binary copolymerization was carried out at various molar ratio of VC and styrene, in ampoules, in the presence of the initiator of benzoyl peroxide,
in a thermostat, at temperature 70°C for 3-4 h.
The copolymer was precipitated with methanol, washed and dissolved in benzene and purified by re-precipitation in methanol. The
isolated polymer was first dried at room temperature, and then in a vacuum box at 313 K and its weight was established.
The characteristic viscosity of the polymer was specified in Ostwald viscometer in a benzene solution at 20°C ([n]=1.16 dl/g for copolymer of VC + styrene). The viscosity was established for the copolymer of VC + styrene including 23.44 and 41.66 mol% VC links, respectively.
The results of elemental analysis are as follows (%): C-88.88; H-6.39, N-4.7, found (%): C-88.25; H-5.92, N-4.5.
The composition of the copolymer was calculated on the content of nitrogen groups established on the methodology given in [19].
When establishing the copolymerization constant, the conversion of monomers was 8-
10%. However, during the synthesis and investigation of the copolymers, the conversion was 80%.
The deformation of the copolymer under the influence of heat under load was studied on the device "Kanafts". The parameters of the copolymer microstructure were established using the equation from the work [20].
IR spectra of the initial monomers and the synthesized copolymer were registered on the spectrometer "Agilent Cary 630 FTIR" of the firm "Agilent Technogies".
The refractive index was determined using a device Anton Paar Abbemat 200.
The spectral transmission coefficients of the copolymer samples were measured using SF-46 spectrophotometer in the wavelength range - 200-1000.
Conclusions
The copolymerization constant values of copolymers (r1=0.032, r2=5.5) have been found. It has been established that M2 monomer shows higher activity than M1 monomer in the radical copolymerization.
The optical transparency of the synthesized copolymer is n^0 = 1.6504, light
transmission - 87-89%.
It found that the copolymer of VC with styrene has good dielectric properties characteristic for PS and PVC. The loss of its mass at 280°C during thermal destruction is ~ 56%.
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N-ViNiLKARBAZOL УЭ STiROL 9SASINDA OPTiKi §9FFAF BiRG9POLiMERiN
SiNTEZi
1S.B. Mammadli, 2F.9. 9mirov, 1A.V. 9bmdarh, 2U.B. Orucaliyeva, 1D.R. Nurullayeva
1Polimer Materiallari institutut, AMEA AZ 5004 Sumqayit, S.Vurgun kug,, 124, e-mail: seide.mamedli@yandex.ru 2Azsrbaycan Dovldt Neft vd Ssnaye Universiteti, AZ1010, Baki, Azadliqpr., 20; e-mail: unalaorujaliyeva12@gmail.com
Xulasa: N-vinilkarbazolun stirol ila birgapolimerla§masi hayata ke^rilmasi naticasinda optiki §affaf birgapolimer sintez edilmi§dir. Birgapolimerla§ma prosesinin qanunauygunluqlari, birgapolimerin tarkib va qurulu§u muayyan edilmi§dir. Fayneman-Ross usulu ila birgapolimerla§ma sabitlarinin qiymatlari muayyan edilmi§dir (ri=0.032, r2=5.5). A§kar edilmi§dir ki, stirol N-vinilkarbazola nisbatan daha yuksak aktivlik gostarir. Birgapolimerin mikroqurulu§ parametrlarinin qiymati muayyan edilmi§dir. 9lda olunan birgapolimer kifayat qadar yuksak i§iqsindirma gostaricisina (n^0 = 1.6504) malikdir. Birgapolimerin i§iqburaxma qabiliyyati 87-89% ta§kil edir. ilkin monomer tarkibini muxtalif nisbatda dayi§makla alinan birgapolimerin tarkibinin onun fiziki-mexaniki xassalarina tasiri muayyan edilmi§dir. Bela ki, birgapolimerin tarkibinda N-vinilkarbazolun manqalarinin miqdari artdiqca birgapolimerin temperaturaya davamliligi duz mutanasib olaraq artir. Muayyan edilmi§dir ki, termodestruksiya zamani bu birgapolimerda 280°C-da kutla itgisi ~5-6%-a barabardir.
A?ar sozlar: N-vinilkarbazol, stirol, birgapolimerla§ma, optiki §affaf birgapolimer.
СИНТЕЗ ОПТИЧЕСКИ ПРОЗРАЧНОГО СОПОЛИМЕРА НА ОСНОВЕ ^ВИНИЛКАРБАЗОЛА И СТИРОЛА
12 1 2 С.Б. Мамедли, Ф.А. Амиров, А.В. Аламдарли, У.Б. Оруджалиева,
1Д.Р. Нуруллаева
1 Институт Полимерных Материалов Национальной АН Азербайджана
АХ 5004 Сумгайыт, ул. С. Вургуна, 124, е-шаИ: seide. mamedli@yandex. ги 2 Азербайджанский Государственный Университет Нефти и Промышленности, АИ010, Баку, пр. Азадлыг, 20; е-шаИ: unalaorujaliyeva12@gmail.com
Аннотация: В результате сополимеризации К-винилкарбазола со стиролом синтезирован оптически прозрачный сополимер. Определены закономерности процесса сополимеризации, состав и структура сополимера. Значения констант сополимеризации определяли методом Фейнемана - Росса (г1=0.032, г2=5.5) Установлено, что стирол проявляет более высокую активность, чем К-винилкарбазол. Определено значение параметров микроструктуры сополимера. Полученный сополимер имеет достаточно высокий показатель светопреломления (п^0=1.6504). Способность светопропускания сополимера составляет 8789%. Варьируя исходный состав сополимера определено влияние состава на физико-механические свойства сополимера. Выявлено, что с увеличением К-винилкарбазолных звеньев пропорционально возрастает термостойкость сополимера. Установлено, что потеря массы этого сополимера при термодеструкции при 280°С составляет ^5-6 %. Ключевые слова: К-винилкарбазол, стирол, сополимеризация, микроструктура, оптически прозрачные материалы
