Hydrated Aluminum Silicate Nanofiber

2023-11-20 10:46:41   264

Nanometer mineral fiber refers to the inorganic mineral fiber or organic/inorganic mineral fiber with a diameter in the nanometer size range (1-1000nm), which has the characteristics of high porosity, large length-to-diameter ratio, large specific surface area, high surface energy and activity, and high fiber fineness and uniformity.

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Introduction to the hydrated aluminum silicate nanofiber

    Hydrated aluminum silicate nanofiber is a new type of nano-mineral fiber material, which has large aspect ratio, hollow tubular structure, good water dispersibility, different properties of internal and external walls, high adsorption, biocompatibility and environmental friendliness. The natural mineral has an inner diameter of 10-20 nm, an outer diameter of 40-70 nm, a length of 200-1000 nm, and a chemical formula of Al2Si2O5(OH)4. The hydrated aluminum silicate nanofibers are formed from kaolin lamellae coiled into tubular structures under natural conditions, so their chemical composition is the same as that of kaolin, but the difference is that aluminum silicate hydrate nanofibers have bound water between layers, and the heat absorption peak of water loss can be seen at about 100℃ through differential thermal analysis. 

    At present, it is mainly used in many fields, such as polymer modification (plastics, rubber, coatings, adhesives, etc.), paper additives, drug controlled release, environmental restoration, oil decoloration, organic additives and catalyst carriers, facial cleaning and moisturizing cosmetics. For example, in the application of modified polymers such as modified PP and PA 6/66, nanofiber materials have outstanding functions of strengthening, flame retardant and promoting carbonization.

    Hydrated aluminum silicate nanofibers have been widely used in the field of environmental pollution remediation because of their good environmental compatibility, large specific surface area, rich surface groups and high adsorption efficiency, as well as the unique characteristics of mesoporous tubular cavities and different charges on the inner and outer surfaces, which can not only be directly used for adsorption and fixation of pollutants, but also be used for catalytic degradation of various organic pollutants. Because of its high aspect ratio and high adsorbability, functional molecules can be adsorbed or grafted on the inner and outer walls of its tubes, it has potential applications in drug carriers and biological detection.

Application of hydrated aluminum silicate nanofibers

Polymer modification

    
The advantages of hydrated aluminum silicate nanofibers as nano-mineral materials for high-performance polymer composites are as follows.
Easy to disperse: Even aluminum silicate fibers without surface modification can achieve good dispersion in almost all solution-mixed or melt-mixed polymers. In particular, aluminum silicate nanofibers are small in size, high in charge and strong in hydrophilicity, and can exist stably in water-based systems.

    Large length-diameter ratio (good reinforcement effect): the length-diameter ratio of aluminum silicate fiber is about 10: 1, and its mechanical strength is high, so it has a good reinforcement effect on polymer materials such as plastic, rubber and coatings, while giving consideration to higher strength and toughness.

    Easy to functionalize and modify (enhance interfacial bonding): the surface of aluminum silicate fiber has active silica-aluminum hydroxyl groups, so it is easy to design modification reactions. Modifying its surface is helpful to increase its interfacial effect with the polymer matrix.

    Easy to load active molecules (preparation of functional composites): aluminum silicate nanofibers have a unique cavity structure, strong adsorption capacity for various molecules, and can control the release of loaded substances. Therefore, it can be used as a new polymer composite with slow release function such as antibacterial agent, anti-corrosion agent, flame retardant, antioxidant, plasticizer and aromatic agent. 

Papermaking additive

    Aluminum silicate nanofibers are added in the papermaking process as paper finishing agents and protective agents. At the same time, aluminum silicate fiber has flame retardant property, and the flame retardant effect of paper can be increased after adding it. The uniform distribution in the structure of plant fiber significantly enhances the mechanical properties and surface hydrophobicity of the paper after addition.

Catalyst and catalyst carrier

    In the petrochemical industry, it can be used as the carrier material of semi-synthetic catalyst for petroleum cracking and oil refining, with the advantages of high catalytic activity, wear resistance and repeated recycling. Compared with ordinary synthetic aluminum silicate and molecular sieve, aluminum silicate nanofibers have unique nanostructures, high catalytic selectivity and high oil yield, and can improve coke selectivity, wear index and hydrothermal stability. Aluminum silicate nanofibers can also be nucleated and crystallized by high-temperature hydrothermal treatment with sodium hydroxide, and then cooled down and completely transformed into zeolite, thus serving as a catalyst for petroleum cracking. It can be used as a catalyst for the epoxidation of soybean oil, and has high catalytic activity and selectivity.

Oil decolorant

    In oil products such as gasoline and edible oil, various impurities cause the color of the oil to be heavy and not clear, affecting the use and appearance of the product. Cracked gasoline products based on heavy oil may contain a lot of unsaturated hydrocarbons, such as dienes. During storage and use, due to the presence of sulfur-containing compounds, these unsaturated hydrocarbons are oxidized in the air to form colloidal substances, which block gasoline pipes, nozzles and intake valves, interrupt oil supply, and forces the engine to stop. Moreover, these colloid substances have a strong coloring ability, and a very small amount of colloid substances can turn colorless gasoline into straw yellow, so it is necessary to decolorize gasoline.Aluminum silicate nanofibers are often used to decolorize oils and fats because of their ion exchange and adsorption properties.

Cosmetic product

    Aluminum silicate nanofibers are not irritating to human skin, and will not cause the
inflammation. Because aluminum silicate nanofibers have a strong adsorption effect on oil or other substances, aluminum silicate nanofibers or organic modified products can be used for face. Aluminum silicate mineral have good thermal conductivity and strong absorption, which can effectively absorb skin oils and toxins, remove aged horniness, refine pores, help to improve the skin mechanism, balance skin PH, reduce and improve skin acne, acne and other problems, and deeply control oil to achieve the effect of beautifying skin. Therefore, hydrated aluminum silicate nanofibers are widely used in cosmetics, facial masks, long-lasting moisturizing cosmetics and other products.