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Modification method of wollastonite
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  • 作者:admin
  • 发布时间:2020-04-06 10:52
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Huayuan Wollastonite Xinyu Huayuan Wollastonite Co., Ltd. Jiangxi Wollastonite

    Huayuan Wollastonite, Xinyu Wollastonite, Jiangxi Wollastonite
Wollastonite as a natural mineral raw material in the industrial application began in the 1930s, wollastonite was only developed and utilized on a larger scale in the 1960s.
 
    Physical method
    The physical method refers to a method for surface modification of inorganic non-metallic mineral fillers without surface modifiers, such as coating modification and high-energy surface modification. Coating modification is a method that uses organic or inorganic materials to coat the powder surface to achieve modification. High-energy surface modification is a method of surface modification using infrared rays, ultraviolet rays, corona discharge, plasma irradiation and ultrasonic waves. The modified system's tensile strength and impact toughness have been significantly improved, its melt temperature sensitivity is good, the viscosity is low, and the processing rheology is also improved. This is beyond the reach of other surface modification methods and is considered a new trend in the surface modification of inorganic non-metallic mineral fillers. However, the process is complex and costly, and it is currently difficult to achieve industrial production.
 
    Chemical method
    The method of using various surface modifiers or chemical reactions to modify the surface of inorganic non-metallic mineral fillers is generally called the chemical method. One end of the surface modifier molecule is a polar group, which can be connected to the surface of the inorganic non-metallic mineral filler by physical adsorption or chemical reaction, and the other end of the lipophilic group can form a physical entanglement or chemical reaction with the matrix. As a result, the surface modifier builds a "molecular bridge" between the inorganic non-metallic mineral filler and the organic polymer, coupling two substances with different polarities and poor compatibility, thereby enhancing the polymer The interaction between the matrix and the inorganic non-metallic mineral filler improves the performance of the product. Surfactants are mostly organic compounds with an asymmetric molecular structure. They are composed of two groups, hydrophilic and hydrophobic. According to the characteristics of the groups and the dissociation state in water, they can be divided into ionic and nonionic types. . When the surface of the hydrophilic filler is treated with a nonionic surfactant, one end of the polar group faces the filler particles and produces an adsorption effect, and the hydrophobic end thereof is outward, resulting in the surface of the hydrophilic filler becoming a hydrophobic surface. Thereby improving the wettability and affinity with the polymer, improving the dispersion effect and reinforcement performance in the rubber. Coupling agent is a chemical substance with double reaction function, which can organically connect rubber and non-carbon black filler, making the interface become a chemical bond, so as to significantly improve the reinforcing performance of non-carbon black filler. The history of the use of silane coupling agents can be traced back to around 1945. The titanate coupling agent was applied late, and the article about the titanate coupling agent for filler was first published by Monte in 1974. The aluminate coupling agent is the first coupling agent in China. Since its advent in 1984, it has attracted attention because of its simple synthesis, low cost, light color, non-toxic, and excellent performance. It has been promoted in the field of materials and has achieved good application results. In addition, there are reports of borate, phosphate, zirconate as coupling agents.
 
    Mechanochemical modification
    Mechanochemical modification is a modification method based on the physicochemical interaction between the chemical agent and the surface of the filler and its active groups, using mechanical-chemical or thermal interaction as a means. At the same time, the powder is ultrafinely pulverized and the surface chemical modification is carried out. The effect of the pulverization mechanical force can be used to promote and strengthen the modification effect. A large amount of mechanical energy applied during the crushing process is not only consumed in particle refinement, but also used to change the crystal lattice and surface properties of the particles, thereby showing activation phenomena. The activated particles can easily react with the modifier. In addition, during the crushing process, the surface of fresh particles constantly appears, and it is also easy to react with the modifier.