CNTs were discovered by Japanese scholars in the early 1990s and immediately attracted great attention from the scientific and industrial fields. CNTs are divided into multi-walled CNTs and single-walled CNTs, which are composed of concentric cylinders formed by curling graphite sheets. Depending on diameter and helicity, CNTs may exhibit metallic or semiconductor properties. With the development of research on CNTs, the composite of CNT and polymer has attracted extensive attention. The composite of CNTs and polymers can form polymer CNT composites, which can realize the complementary or strengthened advantages of the component materials, and can make the most economical and effective use of the unique properties of CNTs.
- Flame retardant materials field: Polymer CNT composites are widely applied to design flame retardant materials. Due to the adding of CNT, the retardancy property of polymer CNT composites can greatly be improved, and the performance is better than nano montmorillonite. Furthermore, after combustion, the material residue can keep a degree of integrity.
- Absorbing materials field: With the advantages of special structure, excellent dielectric property, strong wideband microwave absorption, light weight, adjustable electrical conductivity, strong high-temperature oxidation resistance and good stability, CNTs are promising absorbing materials for stealth materials, electromagnetic shielding materials, darkroom wave-absorbing materials and the others. Based on the above characteristics of CNTs, polymer CNT composites can shield the electromagnetic radiation of mobile phones, computers and other electrical appliances, which is very beneficial to the development of green electrical appliances.
- The others: Polymer CNT composites also have many other applications, including conductive material field, electrostatic spraying field, electrostatic elimination field, thermal conductive material field and the others.
According to the composite way of carbon nanotubes and polymers, polymer CNT composites can be divided into the following groups.
- Polymer filled CNTs: CNTs are hollow cylindric structure and polymers can fill CNTs to form polymer CNT composites. Due to the low filling efficiency of liquid monomer in the CNT and difficulty of the polymerization in CNT, there are few reports on this type polymer CNT composites.
- Polymer coated CNTs: Polymer CNT composites can be formed by coating polymers on the surface of CNTs. After coating CNT with different polymers, the surface properties of carbon nanotubes can be adjusted. Furthermore, polymer CNT composites may have special assembly ability, and can form regular arranged structure or ordered pattern on different substrates, which is very important for microelectronics field.
Figure 1. An example of polymer CNT composites formed by polymer coated CNT.
- Polymer-grafted CNTs: Polymer CNT composites can be prepared by grafting polymer on the surface of CNTs through covalent bond. Due to the covalent bond between the polymer and CNTs, the properties of this type polymer CNT composites are often stable.
Figure 2. An example of polymer CNT composites formed by polymer-grafted CNT.
- CNTs are dispersed in polymer matrix: CNTs with excellent mechanical properties have high aspect ratio and hollow structure, which can be used as reinforced materials for polymer matrix to obtain polymer CNT composites. At the same time, due to the special physical properties of CNTs, the composite material can have microwave absorption, electromagnetic shielding, antistatic properties and the others.
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- Ernould B, Devos M, Bourgeois J P, et al. Grafting of a redox polymer onto carbon nanotubes for high capacity battery materials[J]. Journal of Materials Chemistry A, 2015, 3(16):8832-8839.