Nanotechnology makes it possible to work with parts measured in nanometres (a billionth of a metre). This is a scale just above that of atoms (0.060 nm to 0.275nm) and simple molecules. One criterion is that the structure must measure less than 100 nanometres in at least one dimension.
A nanotube is an elongated nanostructure in the form of a hollow cylinder, usually made from carbon. Nanotubes come in various types, the best known of which is the carbon nanotube. This is a rolled-up layer of graphite, hollow inside, with a length ten thousand times greater than its diameter.
Carbon nanotubes (CNTs) were discovered in the early 1990s. CNT length is measured in micrometres, with diameters less than 100 nm and usually close to 10 nm, depending on the synthesis process. CNTs have a single wall (SWNTs), a double wall (DWNTs) or multiple walls (MWNTs), depending on the number of layers (the C is often omitted in these abbreviations).
In their pure state, CNTs have exceptional mechanical, electrical and thermal properties. Once good CNT dispersion has been obtained, a very low concentration is needed to radically improve the mechanical properties of the material, among other things. The optimal dispersion percentage is usually between 0.1% and 2%.
The load-bearing (nano) polymeric carbon cylinders in Marmox THERMOBLOCK® nano and R2 nano are a direct application of the above technology. The use of Graphistrength® MWNT (carbon nanotubes with 10 to 15 walls with an average outer diameter of 12 nm) in the polymeric concrete leads to mechanical strengthening of the composite material and a perfect balance between λ-value and compressive strength.
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