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AZERBAIJAN CHEMICAL JOURNAL No 3 2020
ISSN 2522-1841 (Online) ISSN 0005-2531 (Print)
UDC 541.64
DEFORMATION PROPERTIES OF COMPOSITE MATERIALS ON THE BASIS OF UNSATURATED POLYESTERS AND EPOXY RESIN
Yu.N.Gahramanly, A.M.Mustafayev*, I.A.Guseynov*, R.I.Ismaylova*, B.N.Babanly,
N.T.Kakhramanov*
Azerbaijan State Oil and Industry University * Institute of Polymer Materials, NAS of Azerbaijan
najaf1946@rambler.ru
Received 22.10.2019 Accepted 17.04.2002
The synthesis of the unsaturated polyester method by the interaction of bicycloheptene dicarboxylic anhydride with glycerin and methacrylic acid and the properties of the obtained product are shown, the results of a study of the influence of various formulation of compositions based on epoxy and polyester resins on the physicomechanical properties and thermomechanical curves of the dependence of deformation on temperature are presented. The paper presents the results of a study of the influence of various formulation of compositions based on epoxy and polyester resin on the physicomechanical properties and thermomechanical curves of the dependence of deformation on temperature. It is shown that compositions with 20 wt. % content of a polyester resin have comparatively better properties.
Keywords: polyester resin, epoxy resin, thermomechanical properties, ultimate tensile stress, elongation at break, heat resistance.
doi.org/10.32737/0005-2531-2020-3-6-10
Introduction
The literature provides a large number of studies on the modification of the structure of epoxy resin ED-20 by loading various modifiers into its composition [1]. The main objective of research, as a rule, is dedicated to the problem of strengthening composite materials, which are widely used in aviation, military, space, military-space technology, shipbuilding, automobile production, building industry etc. Certainly, such a wide range of applications for resin-based potting and impregnating compounds is due to the specific features of their structure and properties. However, regardless of the application areas of the potting compounds, the problem of their strength and heat resistance has always been on the agenda. This circumstance is explained by the fact that precisely these indicators today determine the quality of the material. Obviously, in order to achieve the goal left, it becomes necessary to conduct a series of studies on the development of new composite materials based on epoxy binders of anhydride curing. It is this feature of composite materials that allows them to be used as potting and impregnating compounds in the production of various structural products.
In this regard, the goal of this work was the development of composite materials based on epoxy resin with improved deformation characteristics.
Experimental part
An ED-20 epoxy resin and a synthesized by us polyester resin were used as an object of study.
1. Synthesis of a,«-dimethacrylate-(1.3)-(6is-glycerin)-2-bicyclo [2.2.1]hept-5-ene-2.3-dicarboxylate
In a reaction flask equipped with a mechanical stirrer, a thermometer, a nitrogen capillary, a Dean-Stark nozzle with a reflux condenser, a mixture of 164 g (1 mol) of anhydride and 184 g (2 mol) of glycerin, 392 g (4 mol) of methacrylic acid and 5 g of ^ara-toluenesulfonic acid, 4 g hydroquinone, 500 ml of toluene is heated at 150-1600C, stirring for 4-5 hours until the reaction water is completely stopped.
At the end of the synthesis, the reaction mass, cooled to room temperature, is washed with a 10% aqueous solution of sodium chloride containing 5% sodium carbonate and finally washed with a 5% solution of sodium chloride.
The neutral toluene solution of the oligoester is dried with anhydrous sodium sulfate,
Table 1. Properties of unsaturated polyester (I)
Molecular weight by cryoscopic method in benzene Acid number, mg KOH/g Ether number, mg KOH/g Bromine number g Br/100g OH, % Kinematic viscosity at 300C in 40% styrene
Found Calculated Found Calculated Found Calculated
1100 ± 20 40 ± 10 645 585 35 30 10 7 45 cSt при 200С
after which the solvent is distilled off in vacuo at a temperature of a water bath of 50-600C. The yield of ether is 80-83% of theoretical.
Average molecular weight of the resulting oligoester is the determined by the cryo-scopic method.
The physico-chemical properties of unsaturated polyesters (USPE) are shown in Table 1.
2. Compositions for studying their phy-sicomechanical characteristics were prepared at various ratios of USPE to epoxy resin (10, 20 and 30 parts by weight) polyethylenepoly-amine (PEPA) was used as a curing agent
Samples in the form of spatulas were obtained according to the following procedure. USPE was added to the resin heated to 800C with stirring in small portions. After that, the required amount of PEPA was added to the mixture. The mixture was poured into molds and cured for 24 hours at room temperature, then cured for 6 hours at 800C, 4 hours at 1200C, 3 hours at 1500C.
The degree of curing of the samples 9798% was determined by extraction in the soxhlet apparatus with acetone.
The resulting samples are dark brown in color, transparent, odorless, with a shiny surface. The samples were tested on an FMPW-500 pendulum tensile testing machine with a lower clamp speed of 30 mm/min. The arithmetic average of five measurements was taken as the test results.
On the basis of the C5 fraction obtained during the pyrolysis, dibasic dicarboxylic acid anhydrides were synthesized according to the scheme:
(I)
The unsaturated polyester was synthesized by reacting bicycloheptenedicarboxylic anhydride with glycerin and methacrylic acid:
.CO o
HO II —H2O
O O O 0
-vV^o^yvY
(II)
X = Cl, Br
Based on the C5 fraction obtained during the pyrolysis, dibasic dicarboxylic acid anhydrides, by-products - glycerin and maleic anhydride were synthesized.
Based on these products, unsaturated polyesters were prepared, which at various ratios, were loading into the composition based on ED-20. The use of PEPA made it possible to obtain 3 cured compositions, the formulation of which is given below:
Composition - 1 ED-20 - 45g (90 wt. %) Unsaturated polyester - 5g (10 wt. %) PEPA - 4.5g (10 wt. % in ratio to epoxy resin) The degree of cure of the epoxy composition -98%.
Composition - 2
ED-20 - 45g (80 wt. %) Unsaturated polyester - 10g (20 wt. %) PEPA - 4.0g (10 wt. % in ratio to epoxy resin) The degree of cure of the epoxy composition -98%.
Composition - 3
ED-20 - 35g (70 wt. %) Unsaturated polyester - 15g (30 wt. %) PEPA - 3.5g (10 wt. % in ratio to epoxy resin) The degree of cure of the epoxy composition -98%.
Thermomechanical characteristics of this compositions were studied on a Kanavts instrument in a wide temperature range. Deformation was measured at successively varying temperatures (T). At constructing the thermomechanical curve of the polymer A = f (T), it is very important to cover, if possible, the entire temperature range of the polymer's existence - glassy (crystalline), highly elastic and viscous flow conditions. Thermomechanical curves reflect all possible physical, physico-chemical and chemical changes that occur in the sample in the process of changing the temperature of the experiment and, thus, provide reliable information about the temperature transitions that are significant for polymer processing.
Heat resistance was determined by the Vicat method.
Physicomechanical characteristics were determined by standard methods: ultimate tensile
stress (as) and elongation at break (s) were determined in accordance with GOST 11262-80.
Results and discussion
The composition and ratio of the components included in the main chain of the unsaturated polyester, their mutual compatibility, the degree of polycondensation, polydispersity, the nature of the end groups, the distribution of the structural units of the polymer chain, the composition of the unsaturated units - all together have a significant impact on the properties of the cured resins. In order to get a clear idea of the processes occurring in the ED-20-based polymer composition, it seemed interesting to first consider the regularities of changes in their thermo-deformation characteristics determined by the thermomechanical analysis method. Figure 1 shows the thermomechanical curves of the temperature dependence of deformation for 3 compositions differing in the content of unsaturated polyester. As can be seen from this figure, an increase in the concentration of unsaturated polyester in the composition is accompanied by a significant change in the thermomechanical curves. When the unsaturated polyester content in the composition is within 10 mass. %, noticeable changes in deformation from -48 to +9 |im are observed (Figure 1, curve 1). Moreover, an increase in the experimental temperature from 20 to 500C is accompanied by an increase in the volume of the sample in the range up to 5 |im. At temperatures above 500C, the process of softening of the sample begins, accompanied by an increase in deformation to 9 |im at 700C. Then a further increase in temperature again leads to the reverse process, accompanied by a decrease in deformation and the transition of the composition into a solid glassy state. This state is characterized by the occurrence of intense crosslink-ing, as a result of which an increase in the volume of the sample is observed.
As can be seen from Figure, curve 2, when the content of unsaturated polyester in the composition of ED-20 is within 20 mass. %, an increase in the test temperature to 700C is accompanied by an increase in deformation to 16
|im due to softening of the sample. A further increase in temperature (over 700C) promotes the occurrence of intense crosslinking, which contributes to an increase in the volume of the sample.
The effect of the concentration of the polyester resin in the composition of ED-20 on the ther-momechanical curves of composite materials: composition 1, composition 2, composition 3.
In Figure, curve 3 the thermomechanical curve of the dependence of deformation on temperature is presented for compositions with a 30 mass. % polyester content. According to the data shown in this figure, this dependence is fundamentally different from the thermomechanical curves of the previous two samples. The main difference is expressed in a slight deformation of the samples from the temperature and a shift in the softening temperature of the samples to high temperatures. So, for example, the first softening of the sample begins not at 500C, but at 600C. The curing process does not occur at 700C, but at 820C. And finally, the most important point and distinguishing feature of sample 3 is expressed in the fact that at
1050C the softening of the sample again occurs, accompanied by an increase in deformation.
There is reason to believe that at 30 mass. % of the polyester, such a wave-like course of the process of softening and crosslinking (curing) indicates complex and ambiguous physico-chemical processes taking place in this composition. In addition, there is reason to believe that the curing process of polyester and ED-20 in the composition can proceed in several stages, which is regulated by the viscosity of the mixture. Should take into account the fact that the chain length, as well as the chemical structure of the reagents used, to a certain extent predetermine the structure and properties of the cured polyester.
The ultimate tensile stress and elongation at break of the considered ED-20 compositions were investigated. As can be seen from table 2, all 3 compositions of ED-20 differ in the content of polyester. From a comparative analysis of the data presented in this table, it can be established that composition 2 has a comparatively better strength properties, in which the ultimate tensile stress is 17.0 MPa, the elongation at break is 15%, and the heat resistance is 1600C. In this case, the high heat resistance of the composition is determined, first of all, by that limiting concentration of polyester, at which a uniform redistribution of the crosslinking density is achieved over the entire volume of the sample, and the maximum speed and degree of crosslinking are also ensured.
Table 2. Physico-mechanical properties of composite materials based on ED-20 and polyester resin_
Ultimate Elongation Heat
Composition tensile stress, at break, resistance,
MPa % 0C
Composition 1 11.0 10 150
Composition 2 17.0 15 160
Composition 3 14.0 10 155
Similarly, the compressive strength of the samples was investigated. During the research, it was found that the compressive strength of the samples changes as follows: Composition 1 -4.70 N/mm2, composition 2 - 26.27 N/mm2, composition 3 - 1.08 N/mm . Comparative analysis of the data can establish the maximum value
of compressive strength has a composition with 20 mass. % content. There is reason to believe that in the composition at a polyester concentration of more than 20 mass. %, a certain part of it does not participate in the polycondensation reaction, which leads to a noticeable decrease in the compressive strength of the sample. All obtained experimental data are analytical, since 5 samples were used in the test.
Thus, based on the foregoing, it can be stated that the maximum effect of improving the properties of cured resins is achieved when the content of polyester in the composition ED-20 in the amount of 20 mass. %.
References
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hlor-1,2-epoksipropana. Azerb. him. zhurn. 2006. № 2. S. 127-131.
2. Alekberov N.A., Mustafaev A.M., Murshudova S.D., Arzumanova N.B. Gibridnye matrichnye kompo-zicii na osnove dianovoy smoly ED-20 i trekhlu-chevogo triglicidilovogo oligoefira. Plast. massy. 2008. № 10. S. 20-22.
3. Toropceva A.M., Belogorodskaya K.V., Bondaren-ko V.M. Laboratornyy praktikum po himii i tekh-nologii vysokomolekulyarnyh soedinenij. Leningrad: Himiya, 1972. 415 s.
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6. Hoang The Vu, Osinchik V.S. Modifikacii epok-sidnyh oligomerov alkoksisilanami. Uspekhi v himii i himicheskoj tekhnologii. 2008. T. XXII. № 5 (85). S. 95-98.
DOYMAMI$ POLiEFiRLЭR VЭ EPOKSiD QATRANI ЭSASINDA OLAN KOMPOZiSiYA MATERiALLARININ DEFORMASiYA XUSUSiYYЭTLЭШ
Y.N.Qэhrэmanh, A.M.Mustafayev, i.A.Hйseynov, R.i.ismayllova, B.N.Babanll, N.T.Qэhrэmanov
Bitisklohepten dikarbon anhidridinin qliserin vэ metakril tur§usu ilэ qar§lllqll tэsirindэn doymaml§ poliefirin sintezi usu1u vэ а1шт1§ mэhsulun xassэlэri verilmi§, epoksid qatraш vэ poliefir эsasmda о1ап kompozisiyalanшn muxtэ1if tэrkibinin fiziki-mexaniki xususiyyэt1эrэ vэ deformasiyaшn temperaturdan asl1l1lq эуп1эппэ tэsiri tэdqiqat1aпшn nэticэ1эri tэqdim o1unmu§dur. Tэrkibindэ 20 МАз % ро^и- o1an kompozisiya1ann muqayisэdэ daha yax§l xusu-siyyэt1эrэ ma1ik o1dugu gбstэri1mi§dir.
Лдаг sбzlэr: роНе/гг qatram, epoksid qatram, termomexaniki xususiyyэtbr, dartllmada mдhkэmlik hэddi, тапта, istШyэdavamllllq.
ДЕФОРМАЦИОННЫЕ СВОЙСТВА КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ НА ОСНОВЕ НЕНАСЫЩЕННЫХ ПОЛИЭФИРОВ И ЭПОКСИДНОЙ СМОЛЫ
Ю.Н.Кахраманлы, А.М.Мустафаев, И.А.Гусейнов, Р.И.Исмайлова, Б.Н.Бабанлы, Н.Т.Кахраманов
В работе показано синтез метода ненасыщенного полиэфира взаимодействием бициклогептен дикарбонового ангидрида с глицерином и метакриловый кислотой и свойства полученного продукта, приведены результаты исследования влияния различных составов композиций на основе эпоксидной и полиэфирной смол на физико-механические свойства и термомеханические кривые зависимости деформации от температуры. Показано, что сравнительно лучшими свойствами обладают композиции с содержанием - 20 масс. %. полиэфирной смолы.
Ключевые слова: полиэфирная смола, эпоксидная смола, термомеханические свойства, разрушающее напряжение, относительное удлинение, теплостойкость.
