Table of ContentsIntroductionComparison of carbon nanofiberss and CNTs Morphology Size Processing
Methods PricingAbout Pyrograf
Carbon nanotubes (CNT) and carbon
nanofibers (carbon nanofibers) (also known as stacked-cup carbon nanotubes) share many similarities. They are produced using the same
techniques, are both hollow and their sizes are at the nanoscale level. When it
comes to differences, their size, morphology, processing techniques and prices
vary from each other. In the subsequent sections, these differences will be
discussed in more detail.
Comparison of carbon nanofiberss and CNTs
As mentioned above, carbon nanofibers and CNTs differ mainly in their morphology, processing
method, price and size. Let us now deal with each of the points
have a unique structure called stacked-cup carbon nanotubes (CSCNT). The
graphene plane surface is canted from the fiber axis, which exposes the plane
edges present on the interior and exterior surfaces of the carbon nanofibers. CNTs
have a structure that appears like concentric cylinders. Figure 1 depicts the
differences pictorially by comparing multi-walled carbon nanotubes and
stacked-cup carbon nanotubes.
Figure 1. A) Multi-wall CNTs are composed of concentric
cylinders of graphene where the basal planes form an inert surface. B) The
stacked-cup structure of carbon nanofibers has exposed graphitic edge planes along its length,
providing opportunities for chemical modification of the surface for covalent
bonding directly with the matrix.
The diameter of the fibers of CNT ranges from 1 to 30 nm. On the other hand.
carbon nanofibers come
with diameters of 50 to 200 nm; the diameter depends on the type of the carbon
fiber. CNTs and carbon nanofibers can be several hundred micrometers in length. The
length is determined by the production method and the feedstock.
CNTs experience a greater magnitude of Van der Waals forces due to their
smaller size, while these forces are less in carbon nanofibers. Due to
this difference in forces, CNTs need the intervention of chemical dispersants or
functionalization techniques to help and maintain dispersion. However,
stacked-cup nanofobers are able to stay in the dispersed manner for a longer
time and do not require costly processing methods. The cost of processing carbon nanofibers is much
lesser when compared to CNTs.
The graphene edges are exposed in carbon nanofibers and
hence this structure can be easily changed to enable chemical bonding with any
matrix through chemical functionalization or thermal treatment methods. CNTs on
the other hand require complex processing methods that involve creation of
defect sites along the fiber’s side walls and then bonding with functional
are generally priced much lower than CNTs. Carbon nanofibers are
available in bulk volumes that are priced in the range of 100 to 500 dollars per
pound. On the other hand, the prices of CNTs vary with their quality and purity.
The lower price range is around 100 dollars per pound and for high-quality CNTs
the price can go upto 750 dollars per gram or even more sometimes. As mentioned
in the above paragraph, CNTs require complex processing techniques for
functionalization, which increases their cost.
Products, Inc. (PPI) is one of the leading producers of carbon nanofibers
Products focuses on manufacturing high- quality, low-cost carbon nanofibers
utilizing the proprietary and patented vapor grown carbon fiber (VGCF) process.
Pyrograf-III, developed Applied Sciences, Inc. (ASI), is a versatile vapor grown
carbon nanofiber with a wide range of applications.
This information has been sourced, reviewed and adapted from
materials provided by Pyrograf.
For more information on this source, please visit Pyrograf.