Nanotubes
as a Conductive Additive in Elastomers
Hyperion engineers have discovered that FIBRIL
nanotubes can be compounded into thermosetting elastomers if the elastomer
is thermoplastic before the addition of the cross-linking (curing) agent.
Fluoroelastomers (FKM) are one class of elastomers that give conductivity
at very low (1-2%) nanotube loadings.
The low loading of nanotubes allows the manufacture of conductive O-rings and gaskets that do not compromise the base resin’s low durometer (a measure of the softness of an elastomer). Other conductive additives have to be used at much higher loadings and the resulting compound is much harder (higher durometer) than the normal non-conductive formulation. A higher durometer compound increases the chances of a poor seal, which can cause leaks.
In addition, the low loading of FIBRIL nanotubes gives a conductive FKM formulation with better barrier properties to chemical vapors compared to a formulation based on higher loadings of other conductive additives. Finally, the use of FIBRIL nanotubes gives better retention of conductivity under compression or extension compared to other conductive additives.
Nanotubes as a Potential Flame Retardant
All
plastics are combustible to a greater or lesser degree. The control of plastic’s
combustion with flame retardant (FR) additives is essential in many industries
such as aircraft, building/construction, public transport, and electrical/electronics
equipment.
Flame
retardant
additives work by reducing access to one or more ingredients needed to support
combustion: heat or fuel or air. The control of the toxic byproducts and smoke
is also becoming a factor in assessing flame retardant additives. Increasingly,
FR additives are used in combination, often with a synergistic effect.
Several papers have been recently published on the use of multiwalled nanotubes (both alone and in mixtures with nanoclays) as a flame retardant for plastics. The results are very promising.
The following presentations summarize the results of these papers.
Carbon
Multiwall Nanotubes as Conductive or Fire Retardant Additive for Wire and
Cable (837KB PDF)
Carbon Multiwall Nanotubes A Possible
Additive for Conductive or Flame Retardant Use in Wire and Cable (5.03MB
PDF)
Thermal
and flammability properties of polypropylene/carbon nanotube nanocomposites
(3.5MB PDF)
Related
Article
New
Developments in Nanotube/Polymer Composites (286KB
PDF)
