Nghiên cứu nâng cao tính chất của một số vật liệu polyme bằng khoáng talc biến tính hữu cơ TT TIENG ANH

MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY - NGUYEN VAN THUY STUDY ON IMPROVING THE PROPERTIES OF SOME POLYME MATERIALS BY ORGANICALLY MODIFIED TALC SUMMARY OF MATERIALS SCIENCE DOCTORAL THESIS HANOI – 2021 The thesis was completed at: Graduate University of Science and Technology, Vietnam Academy of Science and Technology Supervisor: Assoc Prof Dr Ngo Ke The Reviewer 1: Reviewer 2: Reviewer 3: The thesis will be defended in front of the doctoral thesis grading committee meeting at the Graduate University of Science and Technology, Vietnam Academy of Science and Technology At …….hour, date…….month…… year 2021 The thesis can be found at: - Library of Graduate University of Science and Technology - Vietnam National Library PREFACE Talc (Mg3Si4O10(OH)2) is a mineral belonging to the group of silicate minerals With its crystal structure, specific physical and chemical properties, talc mineral has been widely applied in many industries such as: ceramics, glass, plastics, rubber, paints and coating materials; paper, agriculture, food industry, and cosmetics Talc is a mineral having a wide application in industries mainly due to its unique surface chemistry and its lamellar crystals structure with high aspect ratio Talc interacts quite well with many matrix polymers [1-4] To improve the interaction between fillers and the polymer matrix, many authors [57] have modified surface of the fillers by silane coupling agents before being put into a polymer matrix Vietnam is a country present on the world map of talc minerals but has not yet exploited and effectively used this special mineral Stemming from the importance of talc minerals as well as the specificity of their ability to interact with substrates, including polymeric matrix, we proposed the doctoral thesis: “Study on improving the properties of some polymeric materials by organically modified talc” The aim of the thesis is: Study on surface modification of talc by silane agents to increase the interaction with rubber and epoxy resin materials Study on using talc to enhance the properties of polymeric materials, typically natural rubber (NR) and NBR/PVC rubber blends; increase the protection and fire resistance of coatings based on epoxy resin The main research topics of the thesis include: Investigation of talc and study of surface modification of talc Research on reinforcement ability of talc mineral for rubber Study on the effect of talc on the protective ability of coatings CHAPTER OVERVIEW 1 Talc and basic characteristics The chemical formulation of talc is Mg3Si4O10(OH)2 [8,9], and it has a sandwich type of crystal structure Talc consists of a layer or sheet of brucite Mg(OH)2 sandwiched between two sheets of silica SiO2 [10] Figure 1.1 Crystal structure of talc [10] Hình 1.2 Talc under the microscope [12] 1.1.1 Physicochemical properties of mineral talc Talc exhibits stability toward heat up to temperatures as high as 16500F (9000C) It has low thermal conductivity and high resistance to thermal shock Pure talc is thermally stable up to 9300C, and loses its crystalline bound water (4,8%) between 9300C and 9700C, leaving an enstatite (anhydrous magnesium silicate) and cristobalite residue Enstatite is significantly harder than talc with a Mohs hardness of 5-6 [28] Most commercial talc products have thermal loss below 9300C on account of presence of carbonates, which lose carbon dioxide at 6000C, and chlorite, which loses water at 8000C Talc’s melting point is at 15000C When heated, talc has a strong thermal effect starting from 9000C, normally 9201060°C if heated in air At this temperature talc is chemically dehydrated to form magnesium metasilicate [29,30]: MgO.4SiO2.H2O MgSiO3 + SiO2 + H2O (talc) Then SiO2 is separated in the amorphous state At 11000C it partially converts to cristobalite with volume expansion Cristobalite has a low density and it compensates for the shrinkage of talc heating Therefore, the volume of talc when calcined is very stable Thanks to its volumetric stability and softness, it allows us to create talc ore into pellets, which can be used as bricks for furnaces and gas fuel combustion chambers 1.1.2 Origin of mineral talc 1.1.3 Chemical composition and composition of talc 1.1.4 Classify Plate talc: This type of talc has a clear, very smooth, sheet-like structure, often containing >90% of the mineral talc (which may be natural or may be processed) This type of talc can be used in cosmetics, pharmaceuticals, and reinforcement Steatite talc: is a type of talc with high purity, dense, very fine grain (may be due to grinding) This type of talc has high insulating properties and is used in the manufacture of insulating porcelain This is the purest commercial talc Soapstone: Less pure talc than steatite talc, which can be carved, sawn, drilled or processed Due to its chemical stability, high heat resistance and consistency, this form of talc can be used to make products such as sinks and stoves Talc tremolite: the kind of fine-grained talc but very hard, usually containing