Application of Nano Calcium Carbonate with Different Morphologies
Nano calcium carbonate, as a new type of high-end inorganic functional filler, exhibits different or abnormal physical and chemical properties from ordinary lightweight calcium carbonate in terms of magnetism, catalysis, photo thermal resistance, and melting point due to its quantum size effect, small size effect, surface effect, and macroscopic quantum tunneling effect. For example, it has special properties in application such as toughening, reinforcement, transparency, thixotropy, leveling, and disinfection and sterilization.
As an excellent material, the performance of nano calcium carbonate depends on its technical indicators, including morphology, chemical composition, particle size distribution, average particle size, etc. Among them, particle morphology is a key factor. Different forms of nano calcium carbonate have different functions and application fields.
Spherical Nano Calcium Carbonate
Spherical nano calcium carbonate has a simple structure, small stacking volume, low oil absorption value, good smoothness and flowability, high coverage, and strong ink absorption. It is mainly used in papermaking, lubricating oil, and electronic ceramics.
Needle Shaped Nano Calcium Carbonate
Needle shaped nano calcium carbonate, also known as whisker calcium carbonate, generally refers to single crystal fiber materials with a length to diameter ratio greater than 10 and a cross-sectional area less than 5.2 × 10-4cm2. Its complete crystal structure makes its reinforcement and toughening functions much greater than those of commonly used toughening agents. As a reinforcing and toughening filler, it can significantly improve the strength, elongation, hardness, wear resistance, and especially enhance the flexural flexibility of rubber. Therefore, needle shaped nano calcium carbonate is expected to replace fiber materials such as glass and asbestos, as well as expensive whisker materials such as potassium titanate and titanium carbide (SiC), and is widely used in industrial fields such as papermaking, plastics, rubber, and coatings.
Chain Shaped Nano Calcium Carbonate
Chain shaped nano calcium carbonate is an excellent rubber reinforcement filler. During the mixing process with rubber, the chain like chains are broken, forming highly active sites that bond with the rubber chains, which improves its dispersibility and greatly enhances its reinforcing effect. Chain shaped nano calcium carbonate can also be mixed with other fillers such as carbon black, white carbon black, titanium dioxide, etc., to improve product processability, color matching, or partially replace expensive white fillers such as titanium dioxide.
Cubic Nano Calcium Carbonate
Cubic nano calcium carbonate is the most stable calcite phase among all calcium carbonate phases at room temperature and pressure. Its stable properties make it the most widely used nano calcium carbonate variety in industry. It has a simple structure, small stacking volume, and good fluidity. When used in paper, it exhibits high shading, flatness, and whiteness; Adding it to plastic can improve its strength, impact resistance, and processability.
Sheet Shaped Nano Calcium Carbonate
Sheet shaped nano calcium carbonate is widely used in the papermaking industry due to its strong surface coating function and covering power, as well as good dispersibility, optical properties, and printability. Especially, when flake nano calcium carbonate is used for coating pigments on copperplate paper, it exhibits good fluidity and dispersibility, with better glossiness and smoothness than ordinary spindle PCC (lightweight calcium carbonate), and can replace or partially replace the increasingly scarce flake kaolin.
Amorphous Nano Calcium Carbonate
Amorphous nano calcium carbonate is a precursor phase for synthesizing various special crystal structures, which does not exist in nature. It has extremely low thermodynamic stability and is easily transformed into a crystal structure, therefore, it needs to be prepared through special methods. Compared with other crystalline products, amorphous nano calcium carbonate has a specific surface area of up to 600 m2/cm3, which is about 20 times that of crystalline products. Therefore, it has extremely high adsorption properties for color and odor, and can release adsorbed gases under certain conditions. It can also be used as an inexpensive toxic metal absorbent and a monodisperse filler for many polymers. So, it is becoming an increasingly eye-catching product.