Structural Application Diversity of Carbon Nanomaterials

wallpapers Innovations 2020-07-31

The Formation of Carbon Nanomaterials

The carbon element in the periodic table contains various allotropes, such as amorphous carbon, graphite, diamond, carbon spheres, carbon nanotubes (CNT), and graphene. And it has various electron orbital characteristics of SP, SP2, SP3 hybridization. In addition, the anisotropy of SP2 leads to the guidance of crystallinity and other arrangements. Three different structures of carbon materials (carbon balls, bamboo-shaped carbon nanotubes, and straight carbon nanotubes) synthesized under H2 catalysis at 1000° C. can be used to change their flow rate by atmospheric pressure chemical vapor deposition (APCVD). Chemical vapor deposition: It is a widely used method for preparing carbon materials, which can be divided into catalytic chemical vapor deposition and non-catalytic chemical vapor deposition. When the gas (or steam) containing carbon source flows over the surface of the catalyst, it will be catalytically decomposed.

Application of Carbon Nanotubes

Carbon nanotubes are seamless hollow tubes made of graphene sheets formed from carbon atoms. They can generally be divided into single-wall carbon nanotubes, multi-wall carbon nanotubes and double-wall carbon nanotubes. Carbon nanotubes (complex mixtures of artificial amorphous and/or crystalline nano-minerals), even in certain geological materials, have been detected in trace concentrations of fullerenes, such as coal-derived fly ash carbon nanotubes are widely used Use, including electronic materials, fuel cells, reinforced composite materials and medical fields. The production methods of carbon nanotubes include arc discharge, laser evaporation, chemical vapor deposition and catalysis. The arc discharge method is not suitable for mass production, but this method can produce high-quality nanotubes.

Main Classification of Carbon Nanospheres

According to the size, carbon nanospheres are divided into: (1) Fullerene family Cn and onion carbon structure (closed graphite layer structure with a diameter of 2-20nm), such as C60, C70 (2) The diameter of incomplete graphite nano-carbon spheres Between 50nm and 1μm. (3) Carbon microsphere structure with diameter greater than 11μm. In addition, according to the structure and morphology of carbon spheres, it can be divided into hollow carbon spheres, solid hard carbon spheres, porous carbon spheres, core-shell structure carbon spheres and colloidal carbon spheres. Some typical carbon nanomaterials, such as nanospheres, can be detected in the clean coal products of low-quality Nagaland (India) coal by molten alkali leaching (MCL), while removing a considerable amount of minerals and sulfur. Coal carbon nanospheres are composed of layered carbon structures. These carbon nanomaterials are not common in this type of coal.

Classification and Characteristics of Carbon Nanofibers

Nanofibers are divided into acrylonitrile carbon fibers and pitch carbon fibers. Carbon fiber is lighter than aluminum and stronger than steel. Its specific gravity is 1/4 of iron and its strength is 10 times that of iron. In addition to its excellent strength, its chemical properties are also very stable, corrosion resistance, high and low temperature, radiation resistance, and deodorization. Compared with single-walled carbon nanotubes, carbon nanofibers are much more economical and practical than single-walled carbon nanotubes. This allows carbon nanofibers to be researched and made into high-functional polymer filler materials, and then mass-produced and used. Generally, the diameter of carbon nanofibers is usually 60-200 nm, and the length is usually 100 lm. In addition, the Young's modulus of carbon nanofibers is 600 GPa, and the tensile strength is usually between 2.5 and 3.5 GPa. Carbon nanofibers can be combined with other polymers to form nano-scale composite materials with excellent properties. Carbon nanofiber materials are generally regarded as the matrix material of composite materials and enhance the overall conductivity and mechanical properties of the composite materials.