Multi Wall CNT

Multi walled carbon nanotubes consists of multiple rolled layers (concentric tubes) of graphite. Their diameter is 3-30 nm and they can grow various cm long, thus their aspect ratio can vary between 10 and ten million. MWCNT have Russian –doll Structure, rigidity, smaller outer diameter, different wall structure, and hollow interior.

MWNTs are highly conductive when properly integrated into a composite structure. The outer wall alone is conducting, the inner walls are not significant to conductivity. MWNTs have a high aspect ratio with lengths typically more than 100 times the diameter, and much higher. Their performance and application is based not just on aspect ratio, but also on the degree of entanglement and the straightness of the tubes, which in turn is a function of the both the degree and dimension of defects in the tubes.

MWNTs with no defects have an excellent tensile strength and when integrated into a composite, such as a thermoplastic or thermoset compounds, can significantly increase its strength. MWNTs have a thermal stability more than 600 °C, based on the level of defects and to certain extent on the purity as residual catalyst in the product can also catalyze decomposition.

MWNTs are an allotrope of sp2 hybridized carbon similar to graphite and fullerenes and as such have high chemical stability. To enhance the both Strength and dispersibility of composites one can functionalize the nanotubes.

MWNTs are suitable for various applications due to its high conductivity and high aspect ratio. The needed conductivity level can be achieved with much lesser loadings than for conventional solutions such as metal particulates or carbon black. Applications are: electrostatic discharge protection in wafer processing fabrication, antistatic elastomeric and plastic components for automobile fuel line components, plastics rendered conductive to enable electrostatic spray painting of automobile body parts, RFI shielding materials, etc.