CC BY
8SMART COMPOSITE IN CONSTRUCTION
УДК 678.019.31
ИССЛЕДОВАНИЕ СВОЙСТВ БАЗАЛЬТОПЛАСТИКА В ПРОЦЕССЕ КЛИМАТИЧЕСКОГО СТАРЕНИЯ
А.Н. Блазнов1'2, В.Б. Маркин3, А.С. Кротов4, В.В. Фирсов4 Н.В. Бычин4, З.Г. Сакошев 4
Алексей Николаевич Блазнов1,2 E-mail: blaznov74@mail. ru
Виктор Борисович Маркин3 E-mail: [email protected]
Анатолий Сергеевич Кротов4 E-mail: [email protected]
Вячеслав Викторович Фирсов4 E-mail: [email protected] Николай Валерьевич Бычин4 E-mail: [email protected] Захар Германович Сакошев4 E-mail: [email protected]
Лаборатория материаловедения минерального сырья, Институт проблем химико-энергетических технологий Сибирского отделения Российской академии наук (ИПХЭТ СО РАН), ул. Социалистическая, 1, Бийск, Алтайский край, Российская Федерация, 659322;
Кафедра машин и аппаратов химических и пищевых производств, Бийский технологический институт (филиал) Алтайского государственного технического университета им. И.И. Ползунова, ул. им. Героя Советского Союза Трофимова, 27, Бийск, Алтайский край, Российская Федерация, 659305; Кафедра современных специальных материалов, Алтайский государственный технический университет им. И.И. Ползунова, пр. Ленина, 46, Барнаул, Алтайский край, Российская Федерация, 656038;
Лаборатория материаловедения минерального сырья, Институт проблем химико-энергетических технологий Сибирского отделения Российской академии наук (ИПХЭТ СО РАН), ул. Социалистическая, 1, Бийск, Алтайский край, Российская Федерация, 659322.
Приведены результаты климатических испытаний однонаправленных базальтопла-стиков после выдержки в климатической камере GRÖNLAND при температуре 60 °С и влажности 100% в течение 1, 2 и 3 мес. Показано, что в первый месяц механические свойства не меняются, после второго и третьего месяца экспозиции модуль упругости образцов возрастает на 6-10 %, предельная деформация уменьшается на 5-7%, прочность практически не изменяется. По результатам термомеханических исследований методом дифференциальной сканируещей калориметрии установлено постепенное повышение температры стеклования образцов от 124.4 °С (1 мес.) до 125.8 °С (2 мес.) и 126.4 °С (3 мес.). Это свидетельствет о дополнительной полимеризации связующего в температурно-влажностных условиях климатической камеры. По результатам цифровой обработки микрофотографий поверхности образцов установлена качественная корреляция между измененем свойств и состоянием поверхности.
Ключевые слова: однонаправленные базальтопластики, климатическое старение, механические свойства, продольным изгиб, температура стеклования, диференци-альная сканируюшая калориметрия, микрофотографии по - верхности, цифровая обработка.
For citation:
Блазнов А.Н., Маркин В.Б., Кротов А.С., Фирсов В.В., Быьчин Н.В., Сакошев З.Г. Исследование свойств базальтопластика в процессе климатического старения. Умные композиты в строительстве. V. 2. No 1. Р. 29-39 URL: http://comincon.ru/index.php/tor/V2N1_2021
DOI: 10.52957/27821919_2021_1_29
UDC 678.019.31
BASALT PLASTIC PROPERTIES UNDER CLIMATIC AGING CONDITIONS
A.N. Blaznov12, V.B. Markin3, A.S. Krotov4, V.V. Firsov4, N.V. Bychin4,
Laboratory of Mineral Materials Science, Institute of Chemical and Energy Technology Problems, the Siberian Branch of the Russian Academy of Sciences (IPCET SB RAS), Socialisticheskaya st., 1, Biysk, Altai Region, Russia, 659322;
Department of Machines and Devices for Chemical and Food Production, Biysk Technological Institute (branch), Altai State Technical University named after I.I. Polzunov, Trofimova st., 27, Biysk, Altai Region, Russia, 659305;
Department of Modern Special Materials, Altai State Technical University named after I.I. Polzunov, Lenina st., 46, Barnaul, Altai Region, Russia, 656038;
Laboratory of Material Science of Mineral Raw Materials, Institute of Chemical and Energy Technology Problems, the Siberian Branch of the Russian Academy of Sciences (IPCET SB RAS), Socialisticheskaya st., 1, Biysk, Altai Region, Russia, 659322.
Zakhar Germanovich Sakoshev 4 E-mail: [email protected]
Z.G. Sakoshev4
Aleksei Nikolaievich Blaznov1,2 E-mail: [email protected]
Viktor Borisovich Markin3 E-mail: [email protected]
Anatoliy Sergeievich Krotov4 E-mail: [email protected]
Viacheslav Viktorovich Firsov4 E-mail: [email protected]
Nikolai Valerievich Bychin4 E-mail: [email protected]
The paper presents results of climatic tests of unidirectional basalt plastics after curing in GRONLAND climatic chamber at 60 °C and 100% humidity for 1, 2, and 3 months. The mechanical properties do not change in the first month, but after the second and third months of exposure elasticity modulo of samples increases by 6-10%, ultimate strain decreases by 5-7%, strength sees almost no change. The results of thermomechanical research using differential scanning calorimetry show the gradual increase of temperature of glass transition of samples from 124.4 °C (1 month) up to 125.8 °C (2 months) and 126.4 °C (3 months). It means that the binder is additionally polymerized in the temperature and humidity conditions of the climatic chamber. After the digital processing of photomicrographs of samples' surfaces, we have established a qualitative correlation between the change in properties and the surface condition.
Key words: unidirectional basalt plastics, climatic aging, mechanical properties, longitudinal bending, glass transition temperature, differential scanning calorimetry, surface photomicrography, digital processing.
For citation:
Blaznov A.N., Markin V.B., Krotov A.S., Firsov V.V., Bychin N.V., Sakoshev Z.G. Basalt plastic properties under climatic aging conditions. Smart Composite in Construction. V. 2. No 1. Р. 29-39 URL: http://comin-con.ru/index.php/tor/V2N1_ 2021
DOI: 10.52957/27821919_2021_1_29
INTRODUCTION
The climatic tests are necessary because of the increasing use of polymer composite materials in chemical industry, aviation, car manufacturing, shipbuilding, various branches of mechanical engineering, and modern construction [1]. The polymer composite materials (PCM) age under operating conditions, which is the result of various physical, chemical, and structural transformations on the surface and inside the structural elements. It is not possible yet to predict reliably the change of mechanical parameters of PCM when using more than 30-50 because there is insufficient knowledge about their ageing considering the synergistic effect of daily and seasonal cycles of temperature, humidity, solar radiation, precipitation, wind, and mechanical loads [1].
There is a significant impact on polymer composites used in construction that comes from atmospheric factors (temperature, humidity, solar radiation, etc.), which, as aging facilitators, contribute to the development of physical and chemical processes in the materials and during the operation may significantly reduce their properties [1, 2]. Most PCM used in construction are in direct contact with air or water. A great number of modern studies in Russia [3-8] and internationally [9-18] are devoted to problems of durability of PCM under the effect of increased temperature, humidity, and mechanical loads.
There are studies of the durability of carbon and glass plastics in seawater [10, 11], UV resistance of wood-polymer [12] and hybrid composites [13]. The durability of fiberglass plastics under the combined effects of moisture and mechanical loads was investigated in [14], of temperature and load — [15]. Glass-epoxy, car-bon-epoxy and hybrid composites under hydrothermal aging conditions were studied in [9, 16]. The long-term strength of polymer composite reinforcement was also studied in a concrete environment [17], and the durability of basalt plastics was studied at an increased temperature [18].
The current world practice is to establish relationships between surface degradation and changes in composite material properties [19-24]. This allows a non-destructive way to perform an express analysis of its condition and evaluate the critical change of properties as a result of aging. The authors propose an original method for analyzing climatic aging of PCM based on digital processing of surface photomicrographs [25], which follows the advanced trends in the field of polymer construction materials science. The method has been tested and the relationship between the sample surface condition and the change in physical-mechanical and thermome-chanical properties as a result of climatic aging has been established [8].
The purpose of this work is to study the degradation of basalt plastic properties during climatic aging under conditions of elevated humidity and temperature.
EXPERIMENT
Samples for research were produced in the form of unidirectional basalt plastics using basalt roving BCF17-2520-KV13 (Kamenniy Vek, Dubna) and hot-cured epoxyhydride binder EDI: ED-22
epoxy resin (100 wt. %), iso-MTGFA hardener (85 wt.%), accelerator UP-606/2 (1 wt. %) [26].
Unidirectional samples of basalt plastics were made by winding using the authors'patented method [27]. The technology of making such samples is described in more detail in [28]. The method of producing unidirectional plates is based on tight winding (turn to turn) of a cylindrical shell of binder-impregnated roving on a metal mandrel (Fig. 1, a), followed by cutting (Fig. 1, b), unfolding to sheet (Fig. 1, c), under-pressing in the mold, and polymerizing the product as follows: 0.5 h at 120°C, then 4 h at 150°C. Thus, three unidirectional sheet samples of basalt plastic (named Z1, Z2, Z3 for convenience) were produced. All 3 sheets were produced with the same binder, same batch of roving, same winding, pressing, and curing.
After the sheets were cured, thin plates were cut out of them as samples (12 mm wide and with the same sheet thickness without treating the outer surface) and tested as is by the longitudinal bending method [29, 30] (Fig. 1, d). The test results are shown in Table 1.
The samplesfrom each batch were subjected to unloaded climatic testing at 60°C and 100% humidity in a GRÖNLAND climatic chamber: samplesfrom batch Z1 - for 1 month, samplesfrom batch Z2 - for 2 months, samplesfrom batch Z3 - for 3 months.
The choice of temperature and humidity for testing was based on publicly available data and previous studies of the authors. The territory of Russia is notable for its large geographical length that covers a large number of climatic zones - from extremely cold (Yakutsk, Far North, and the Arctic) to warm humid sea (Sochi, Gelendzhik). It is established that cold and moderate climate renders the least destructive influence on a composite, and warm humid climate impacts it the most. Therefore, the choice of temperature 60 °C and humidity of 100% in the climatic chamber is due to the worst-case scenario of PCM operation.
After climatic aging, the samples were subjected to mechanical longitudinal bending tests, DSC analysis to determine the thermo-mechanical properties and examine the surface state of the samples by digital processing of photomicrographs.
The data of mechanical tests for longitudinal bending of samples after climatic exposure are given in Table 2.
The data in Tables 1, 2 show that in the first month of exposure there was almost no change in the mechanical properties of basalt plastic samples. In the second and third months the elastic modulus E increased noticeably (by 6-10%), the critical strain £, respectively, decreased by 5-7% with the strength a practically unchanged. Additional polymerization of material at temperature 60°C and humidity 100% could result in the increase of elastic modulus (increase of stiffness of samples) [8].
To study the thermomechanical properties, tests were conducted according to ISO 11357-2:1999 [31] by differential scanning calo-rimetry (DSC). We determined exo-effects on NETZSCH DSC 204 F1 with the speed of heating samples 10 ° C / min to 200-250 ° C in an inert nitrogen environment flowing through the measuring cell at 30 ml / (min- ° C). Typical DSC diagrams of the field samples of climatic tests are shown in Fig. 2.
c d
Fig. 1. Demonstration of the method of manufacturing sheet samples of winding products [28]: a-wet winding of the roving on the mandrel (turn to turn); b - cutting of the wound billet along the axis; c - reaming and pressing of the sheet; d - testing of samples for longitudinal bending
Table 1. Test results of unidirectional basalt plastics in the initial state
Batch marking L, mm b, mm s, mm £, % Е, MPa a, MPa
Z1 99.9 11.97 2.09 4.27 42684 1569
99.8 11.75 2.27 4.20 41900 1629
100.2 11.53 2.19 4.02 42504 1516
Average value 4.16 42363 1571
Z2 100.0 12.53 1.99 3.97 45739 1613
100.3 12.75 2.08 3.71 42754 1298
100.3 11.97 2.06 3.97 45393 1611
Average value 3.88 44628 1508
Z3 100.0 11.89 2.23 4.12 42190 1501
100.0 11.92 2.20 4.06 41870 1610
100.0 11.97 2.19 4.02 41398 1488
Average value 4.06 41819 1533
Legend: L - sample length, b - sample width, s - sample thickness, £ - critical strain (at crushing), a - strength, E - elasticity modulus.
The peak on the curves corresponds to the glass transition temperature. Note that as the samples stay in the thermo-moisture conditions of the climatic chamber, the glass transition tempera-turegradually increases-from 124.4 °C (Z1, 1 month) to 125.8 °C (Z2, 2 months) and 126.4 °C (Z3, 3 months). This confirms the f-fect of binder post-curing, an increase in the elastic modulus observed earlier in [8] and explained by the catalytic effect of moisture on epoxy polymer post-curing in [24, 32, 33]. The essence of
the effect: when plasticizing with moisture, the efficiency of intermolecular interaction decreases, the active groups acquire greater mobility, due to which additional transverse bonds are formed. The glass transition temperature, elastic moduli, and strength of epoxy polymers increase after removing moisture [8, 24, 32, 33].
УМНЫЕ КОМПОЗИТЫ В СТРОИТЕЛЬСТВЕ
SMART COMPOSITE IN CONSTRUCTION
Table 2. Results of longitudinal bending tests of unidirectional basalt plastics after climatic aging in the GRONLAND chamber at a temperature of 60 ° C and a humidity of 100%
Batch marking, exposure time L, mm b, mm s, mm £, % Е, MPa a, MPa
Z1 (1 month) 100.0 11.99 2.07 3.49 40072 1307
100.0 12.05 2.02 4.20 43703 1562
100.0 11.95 1.97 4.10 42203 1512
100.0 12.04 2.23 4.21 40641 1546
100.0 12.04 2.22 3.97 39650 1433
Average value 3.99 41254 1472
Z2 (2 months) 100.0 12.06 1.88 3.81 46384 1579
100.0 12.01 1.77 3.67 46150 1487
100.0 12.07 1.89 3.84 45756 1517
100.0 12.08 1.90 3.39 48313 1524
Average value 3.68 46651 1527
Z3 (3 months) 100.0 11.99 1.96 3.37 46713 1490
100.0 12.04 2.12 4.08 43232 1538
100.0 11.99 2.17 4.08 45181 1543
100.0 12.11 2.12 3.68 45514 1509
100.0 11.89 1.93 3.91 46784 1561
Average value 3.82 45485 1528
The changes on the surface of samples as a result of climatic effects was studied using the original method of digital processing of surface photomicrographs [25]. Anaconda 3 development environment (https://www.anaconda.com/) was used to make histograms that show the gradation distribution of gray depicted in the photomicrographs of samples taken from three types of basalt plastics in
the initial state and after climate aging. Examples of histograms are presented as follows: Top - the original image, next - the histogram of shades of gray (blue columns), and the cumulative distribution function (CDF) - a red curve (https://en.wikipe-dia.org/wiki/cumulative distribution function) (Fig. 3).
a)
SMART COMPOSITE IN CONSTRUCTION
c)
Fig. 2. DSC diagrams of basalt plastic samples after climatic aging in the GRONLAND chamber at a temperature of 60 ° C and humidity of 100%: a - sample Z1 after exposure for 1 month, b - sample Z2 after exposure for 2 months, c - sample Z3 after exposure for 3 months
SMART COMPOSITE IN CONSTRUCTION
Pixel intensity
c)
Fig. 3. Photomicrographs of the surface of the samples basalto-plastica (magnification x 500) after the climatic aging in the camera GRONLAND at a temperature of 60 ° C and humidity
100% and their digital processing: a - Z1 sample after incubation for 1 month, b - Z2 sample after incubation for 2 months, c - sample Z3 after incubation for 3 months
The difference between the states of exposure (initial, after climatic effect) were assessed by comparing the cumulative distribution function (CDF) (Fig. 4).
The difference of CDF functions for samples Z1 and Z2, Z1 and Z3 shows the structural changes in the surface of the samples after their exposure in the climatic chamber for 2 and 3 months. Comparing these data with the results of mechanical and thermome-chanical tests, it can be stated that there was a climatic impact, but the destruction of the surface and structure of the composite did not occur (the properties even slightly improved). This is due to the short time of the basalt plastic samples in the climatic chamber.
b)
Pixel intensity
Fig. 4. Comparison of cumulative distribution functions (CDF) of samples from batches Z1-Z3 after climatic aging (solid lines), dotted lines - the difference between the CDF functions
CONCLUSIONS
1. The climatic research of unidirectional basalt plastics has been carried out at exposure in unloaded condition at 60 °C and 100% humidity in climatic chamber GRONLAND for 1, 2, and 3 months.
2. Determining the mechanical properties of the samples by the longitudinal bending method, showed that the properties of the samples stayed almost the same in the first month of climatic aging, but in the second and third months, the elastic modulus increased by 6-10%, the critical deformation during the destruction decreased by 5-7% compared to the initial samples, while the strength also stayed at the same level.
3. The study of the thermomechanical properties of samples by the method of differential scanning calorimetry showed an increase in glass transition temperature from 124.4 °C (1 month) to 125.8 °C (2 months) and 126.4 °C (3 months). This occured due to the catalytic effect of moisture on curing of epoxy polymers.
4. The digital processing of photomicrographs of the samples' surface after climate aging revealed structural changes for samples after 2 and 3 months of exposure. Thus, a qualitative relationship is established between the change in the properties of the samples (on the macro level) and the change in the state of their surface (at the micro level) according to the data obtained from the photomicrographs of the surface.
5. Climatic tests of basalt plastic samples at 60 °C and 100% humidity for 3 months led to an improvement in mechanical and thermomechanical properties. It follows from this that the exposure time was insufficient in order for noticeable destructive changes in composites.
The work was conducted using the equipment of the Biysk Regional Center for Collective Use, Siberian Branch of the Russian Academy of Sciences (IPCET, Siberian Branch of the Russian Academy of Sciences, Biysk).
REFERENCES
Startsev V.O. Climatic stability of polymer composite materials and protective coatings in a moderately warm climate: abstract of dis. ... Doctor of Technical Sciences. 05.16.09. M. 2018. 48 p. (in Russian).
Kablov E.N., Startsev O.V., Krotov A.S., Kirillov V.N. Climatic aging of composite materials for aviation purposes. III. Significant factors of aging. Deformation and destruction of materials. Deformatsiya i razrusheniye materialov. 2011. N 1. P. 34-40. (in Russian).
Startsev O.V., Erofeev V.T., Selyaev V. P. Climatic tests of building materials: monograph. M.: Publishing house ASV. 2017. 558 p. (in Russian).
Startsev O.V., Blaznov A.N., Petrov M.G., Atyasova E.V. A
Study of the Durability of Polymer Composites under Static Loads. Polymer Science, Series D. 2019. V. 12. N 4. P. 440448.
Blaznov A.N., Zimin D.E., Anisimov E.E., Sinitsin A.V., Zhurkovsky M.E. Study of the durability of composites under the influence of load and high humidity. Nauchno-tekhnich-eskiy vestnik Povolzhia. 2018. N11. P. 98-101. (in Russian). Blaznov A.N., Krotov A.S., Zhurkovsky M.E., Zimin D.E., Samoylenko V.V., Firsov V.V. Moisture diffusion in basalt plastics. Polzunovskiy vestnik. 2019. N 4. P. 95-100. (in Russian).
Startsev O.V., Medvedev I.M., Krotov A.S., Panin S.V. Dependence of the surface temperature of samples on the characteristics of the climate during exposure in natural conditions. Korroziya: materialy i zashchita. 2013. N 7. P. 43-47. (in Russian).
Blaznov A.N., Krotov A.S., Markin V.B., Firsov V.V., Zhurkovsky M.E., Bychin N.V., Sakoshev Z.G. Changes in
the physical-mechanical and thermomechanical properties of basalt plastics as a result of climatic aging. Yuzhno-Sibirskiy nauchnyy vestnik. 2019. N 3(27). P. 116-120. (in Russian).
9. Noamen Guermazi, Amira Ben Tarjem, Imen Ksouri. On the durability of FRP composites for aircraft structures in hy-grothermal conditioning. Composites Part B: Engineering. 2016, V. 85. P. 294-304.
10. Kootsookos A., Mouritz A.P., John N.A. St. Comparison of the seawater durability of carbon- and glass-polymer composites. URL: http://iccm-central.org/Proceedings/ICCM13pro-ceedings/SITE/PAPERS/Paper-1200.pdf
11. Dikne Ndiaye, Elisabeth Fanton, Sandrine Morlat-The-rias. Durability of wood polymer composites: 1. Influence of wood on the photochemical properties. Composites Science and Technology. 2010. N 68 (13). P. 2779.
12. Demkowicz, Mackenzie. Environmental Durability of Hybrid Braided Polymer Matrix Composites for Infrastructure Applications (2011). URL: https://digitalcom-mons. library.umaine.edu/etd/1575.
13. Jun Wang, Hota GangaRao, Ruifeng Liang et al. Durability of glass fiber-reinforced polymer composites under the combined effects of moisture and sustained loads. Journal of Reinforced Plastics and Composites. 2015. V. 34. P. 1739-1754.
14. Jaehyeuk Jeon, Anastasia Muliana, Valeria La Saponara. Thermal stress and deformation analyses in fiber reinforced polymer composites undergoing heat conduction and mechanical loading. Composite Structures. 2014. V. 111. P. 31-44.
15. Abdel-Hamid Ismail Mourad, A mir Hussain Idrisi, Maria Christina Wrage. Long-term durability of thermo-set composites in seawater environment. Composites Part B: Engineering. 2019. V. 168. P. 243-253.
16. Yucheng Zhong, Mingyang Cheng, Xin Zhang et al. Hygro-thermal durability of glass and carbon fiber reinforced composites - A comparative study. Composite Structures. 2019. V. 211. P. 134-143.
17. Moyeenuddin Ahmad Sawpan, Abdullah A. Mamun, Peter G. Holdsworth. Long term durability of pultruded polymer composite rebar in concrete environment. Materials & Design. 2014. V. 57. P. 616-624.
18. Ahmed H. Ali, Hamdy M. Mohamed, Brahim Benmokrane. Durability performance and long-term prediction models of sand-coated basalt FRP bars. Composites Part B: Engineering. 2019. V. 157. P. 248-258.
19. Startsev V.O., Lebedev M.P., Frolov A.S. Influence of climatic influence onfractography of destruction of epoxy polymers. Plasticheskiye massy. 2018. N11. P. 36-41. (in Russian).
20. Startsev V.O., Lebedev M.P., Frolov A.S., Nizina T.A. Interrelation of deformability and fractographic characteristics of the fracture surfaces of epoxy polymers. Doklady Akademii Nauk. 2017. V. 476. N1. P. 55-58. (in Russian).
21. Startsev V.O., MolokovM.V., Startsev O.V., Nizin D. R. Influence of the aliphatic solvent ETAL-1 on the climatic stability of epoxy polymers based on ED-20 resin. Vse materialy. Entsiklopedicheskiy spravochnik. 2016. N 12. P. 26-36. (in Russian).
22. Startsev V.O., Nizina T.A., Startsev O.V. Color criterion of climatic aging of an epoxy polymer. Plasticheskiye massy. 2015. N 7. P. 45-47. (in Russian).
23. Panin S.V., Startsev O.V., Krotov A.S., Medvedev I.M.,
Frolov A.S. Corrosion and aging of the surface of structural
materials according to 3D microscopy data. Trudy VIAM. 2014. N12. P. 12. (in Russian).
24. Startsev V.O., LebedevM.P., Khrulev K.A., MolokovM.V., Frolov A.S., Nizina T.A. Effect of outdoor exposure on the moisture diffusion and mechanical properties of epoxy polymers. Polymer Testing. 2018. V. 65. P. 281-296.
25. Blaznov A.N., Krotov A.S., Markin V.B., Firsov V.V., Zhurkovsky M.E., Bychin N.V., Sakoshev Z.G. Express analysis of photomicrographs of basalt plastic samples in the initial state and after climatic aging. Yuzhno-Sibirskiy nauch-nyy vestnik. 2019. N 3(27). P. 108-115. (in Russian).
26. BlaznovA.N., Atyasova E.V., Shundrina I.K., Samoilenko V.V., Firsov V.V., ZubkovA.S. Thermomechanical characterization of BFRP and GFRP with different degree of conversion. Polymer Testing. 2017. V. 60. P. 49-57.
27. Samoylenko V.V., Blaznov A.N., Firsov V.V., Zimin D.E., Khodakova N.N., Uglova T.K. Patent of the Russian Federation N 2597811. 2016. (in Russian).
28. Zhurkovsky M.E., Sakoshev Z.G., Blaznov A.N., Zimin D.E., Firsov V.V., Samoylenko V.V., Khodakova N.N. Investigation of mechanical properties of winding hybrid polymer composite materials. Yuzhno-Sibirskiy nauchnyy vestnik. 2018. N 3(23). P. 39-43. (in Russian).
29. Blaznov A.N., Savin V.F., Volkov Yu.P., Rudolf A.Ya., Startsev O.V., Tikhonov V.B. Methods of mechanical testing of composite rods: monograph. Biysk: Publishing House of Alt. state Technical University,. 2011. 314p. (in Russian).
30. Rudolf A.Ya., Pozdeev S.P., Savin V.F., Lugovoy A.N., BlaznovA.N., Startsev O.V., Tikhonov V.B., LoktevM.Yu. Patent of the Russian Federation N 2451281. 2012. (in Russian).
31. GOST R 55135-2012 (ISO 11357-2: 1999). Plastics. Differential scanning calorimetry (DSC). Part 2. Determination of the glass transition temperature. (in Russian).
32. Startsev O.V., Perepechko I.I., Startseva L.T., Mashinskaya G.P. Structural changes in plasticized mesh epoxy polymer. Vysokomolekulyarnyye soyedineniya. Seriya B. 1983. V. 25. N 6. P. 457-461. (in Russian).
33. Startseva L.T., Panin S.V., Startsev O.V., Krotov A.S. Moisture diffusion in glass-fiber-reinforced plastics after their climatic ageing. Doklady Physical Chemistry. 2014. V. 456. N1. P. 77-81.
Received 26.02.2021 Accepted 15.03.2021
