Аннотация. Задача создания технологии упрочнения эпоксидной смолы (ЭС) и углепластика актуальна для многих разделов техники: космической, авиационной, оборонной, автомобильной и др. Вопрос решается многочисленными приемами модификации ЭС, компонентов углепластика. Модификация ЭС осуществляется путем ввода различных химических соединений. Одним из методов упрочнения углепластика является модификация пластификаторами (трикрезилфосфат, олеиновая кислота) или термопластами (полисульфон, поликарбонат, полистирол, ударопрочный полистирол). В работе собраны имеющиеся в литературе экспериментальные данные по влиянию различных видов модификаторов на прочность ЭС и углепластика. Проанализирован механизм модифицирования ЭС и углепластика пластификаторами и термопластами. Введение пластификаторов в качестве модификаторов ЭС приводит к улучшению ударной вязкости в 2 раза. Оптимальный ввод пластификаторов в ЭС составляет 15 % и зависит от полноты растворимости в связующем, дальнейшее увеличение ввода пластификатора приводит к снижению прочности материала. Модификация термопластами углепластика может привести к улучшению прочности на сжатие на 20% и ударной вязкости в 2 раза. При введении термопластов свыше 20% в углепластик показатели прочности снижаются. Полученные данные необходимы для разработки отечественной технологии производства ударопрочных углепластиков. Ключевые слова: эпоксидная смола, модификаторы, пластификаторы, термопласты, термообработка, ударная вязкость, прочность.Мустафа Л.М. -Ph.D. студент, старший научный сотрудник в АО «Национальном центре космических исследований и технологий», Алматы, Казахстан. ORCID ID: 0000-0002-9779-0007.
stuDy on the effect of plAstIcIZers AnD therMoplAstIcs on the strenGth AnD touGhness of epoxy resIns purpose. To increase the strength and toughness of epoxy resins of "cold hardening" and "hot hardening" by using modified plasticizers and thermoplastic polymers. Methodology. Epoxy resins of "cold hardening" of ED20 and "hot hardening" of Etal InjectT, modified with three types of plasticizers and four types of thermoplastic polymers, were investigated. The toughness and compressive strength of unmodified and modified resins were determined with the help of the Charpy impact test at various modifier contents. findings. Among all studied plasticizers, tricresyl phosphate has the most significant effect on the strength and toughness of both types of resins. The best combination of strength and toughness of ED20 resin is obtained with 5 % tricresyl phosphate con tent, whereas its higher content reduces the strength of the material. For Etal InjectT, high values of these properties are obtained with 15 % tricresyl phosphate content, whereas adding a smaller amount of a modifier does not change the material strength. The modification with thermoplastic polymers has a less obvious effect on the properties of epoxy resins than the modification with plasticizers does. The most effective additives to ED20 are hightemperature polycarbonate (5 %) and polysulfone (10 and 15 %), the addition of which causes a simultaneous increase in both properties. A significant increase in the toughness of Etal InjectT is observed by adding 5-15 % polycarbonate, but the strength of the resin hardly changes. The complex modification of resins with a mixture of plasticizer and thermoplastic leads to a decrease in the toughness and compressive strength of both types of resins. originality. When the polymer mixture hardens, plasticizer molecules dispersed into the environment of epoxy macromole cules weaken the rigid spatial crosslinking of macromolecules and make them more active. As a result, toughness increases; in certain cases so does resistance due to directed reorientation of macromolecules under deformation. The change in mechanical properties of epoxy resin when modified with thermoplastics is defined by the bonding strength of the resin and dispersed particles of thermoplastic polymer as well as by the degree of heterophase of the produced mixture. practical value. The results of changing the mechanical properties of epoxy resin while being modified with plasticizers and thermoplastics can be used to produce impactresistant composite materials for structural purposes, including those for aviation and spacerocket technology.
The possibilities of porosity adjustment in alloys of the Mg-Al-Zn system obtained by melting under a layer of flux were studied. The elements that significantly increase corrosion resistance and heat resistance, and improve mechanical strength and technological characteristics were chosen as doping components. Measurements showed that the range of porosity varied between 5.9 and 14.8%, and the relationship between porosity and strength of alloys was defined for the first time for this range.For an alloy with porosity of 14.8%, the percentage of open pores was 12.8% while the percentage of closed pores was 2%. Micro-hardness of alloys with the given porosity was 661 MPa after casting, 876 MPa after homogenizing annealing and 897 MPa after artificial aging. The tensile strength was 235 MPa. Analysis identified that the main cause of porosity was catching atoms of hydrogen from atmosphere by molten alloys during melting, casting and liquation. In order to reduce the percentage of porosity alloys were doped by metal manganese, liquid metal was processed by calcium and hexachloroethane, and casting form was treated by boron nitride. These manipulations resulted in reduction of samples porosity up to 5.9%, increase of tensile strength up to 240 MPa. Open porosity was 4.5%, while closed porosity was 1.4%. At the same time micro-hardness of cast samples was 867 MPa, 903 MPa after homogenization annealing and 961 MPa after artificial aging. Further reduction of porosity and increasing of magnesium alloys strength is possible with the use of inert gases or vacuum melting. Samples porosity can be increased by more than 14.8% with the help of melting in the hydrogen containing atmosphere.
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