Pyrograf III

Pyrograf III is a patented, very fine, highly graphitic, yet low cost, carbon nanofiber.  Pyrograf III is available in diameters ranging from 70 and 200 nanometers and a length in excess of 100 microns.  Therefore, nanofibers are much smaller than conventional continuous or milled carbon fibers (5-10 microns) but significantly larger than carbon nanotubes (1-10 nanometers).  CNF is discontinuous fibrous reinforcement for engineered composites with an inherently low processing cost.  In equivalent production volumes, CNF is projected to have a cost comparable to E-glass or a per-pound basis, yet possesses properties which far exceed those of glass and are equal to or exceed those of much more costly commercial carbon fiber.  Because it is a discontinuous reinforcement, CNF can be incorporated into commercially available thermoplastics, thermosets and elastomers and can be used directly in existing high volume molding processes without any significant new manufacturing development.  Because of its extraordinary intrinsic properties, particularly its strength and elastic modulus, CNF is expected to enable a reduction in the material required to produce a given strength and/or stiffness, thus providing net weight and cost savings.  Furthermore, CNF is produced in a process very similar to that of carbon black, directly from a simple hydrocarbon source.  The economies of scale in this process are therefore not tied to the production costs associated with spun textile.

Pyrograf III carbon nanofiber is offered in two types and in three grades each, which are identified in the tables below.

Pyrograf III is a multifunctional material which provides enhanced electrical conductivity over a broad range along with mechanical reinforcement of matrix materials.

 

TEM Image of Pyrograf III Carbon Nanofiber

Other benefits provided by the nanofiber include improved heat distortion temperatures and increased electromagnetic shielding.  Although direct measurement of many properties cannot be obtained by conventional methods, the physical properties of more graphitic forms of vapor grown carbon fiber are known to tend towards single crystal graphite.  (See Pyrograf-I data)

 

PYROGRAF III PROPERTIES:

Nano-
fiber Type
Nano-
fiber Grade
N2Surface Area, (m2/gm) Dispersive Surface Energy, (mJ/m2) Moisture Content
(%)
Iron Content
(ppm)
PAH Content (mg PAH/g fiber) Density (lbs/ft3)
PR-19 PS 20-30 120-140 <5 <14,000 <1 2-4
PR-19 LHT <5 <14,000 <1 2-4
PR-19 HHT 15-25 265-285 <5 <100 <1 2-4
PR-24 PS 50-60 <5 <14,000 <1 2-4
PR-24 LHT <5 <14,000 <1 2-4
PR-24 HHT <5 <100 <1 2-4

Pyrograf III has a unique structure sometimes referred to as stacked-cup carbon nanotubes (SCCNT).  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. The following figures depict this unique stacked-cup structure.

Artist’s Depiction of Pyrograf II Stacked-Cup Carbon Nanotubes

Cross sectional view showing the internal structure of Pyrograf Products Stacked-Cup Carbon Nanotubes

 

 

 

 

 

 

 

 

 

 

 

 

PYROGRAF III GRADES:

PR-19-XT PR-24-XT
Production Full scale Full scale
Diameter, nanometers 100 to 200 60 to 150
Length, nanometers 30,000 to 100,000 30,000 to 100,000
Comments As grown material contains CVD carbon As grown material essentially free of CVD carbon

 

 

 

 

 

 

Thermal Processing

  • PS – pyrolytically stripped carbon fiber
    • Removes polyaromatic hydrocarbons from surface
  • LHT –  Low heat treated carbon nanofiber
    • Heated to temperatures up to 1,500°C
    • Partially graphitizes chemically vapor deposited carbon present on the surface of Pyrograf
  • HHT – High heat treated carbon nanofiber
    • Heated to temperatures up to 2,900°C
    • Graphitizes chemically vapor deposited carbon present on the surface of Pyrograf
    • Creates a highly electrically conductive carbon nanofiber
    • Removes iron catalyst from carbon nanofiber

Available product grades

  • PR-19-XT
    • PS – Pyrolytically stripped carbon nanofiber
    • LHT – Low heat treated carbon nanofiber
    • HT – High heat treated carbon nanofiber
  • PR-24-XT
    • PS – Pyrolytically stripped carbon nanofiber
    • LHT – Low heat treated carbon nanofiber
    • HT – High heat treated carbon nanofiber

Product forms

  • Bulk nanofiber shipped as free flowing powder
  • Masterbatch resins
  • Specialty papers

 

BENEFITS:

COMPOSITES MADE FROM PYROGRAF NANOFIBERS SHOW THESE BENEFITS TYPICAL APPLICATIONS FOR CARBON NANOFIBER COMPOSITES
  • Low fiber loadings
  • Class “A” surface finish
  • Uniformly conductive surfaces
  • Enable thin walled molds
  • Reduced cycle times
  • Lower specific gravity
  • Static dissipation
  • Lower cost composites
  • carbon cathodes and anodes
  • Industrial applications
    • Silicon wafer production
    • Batteries and fuel cells
    • Disk drive components
    • Clean rooms
  • Automotive uses
    • Fuel systems
    • Mirror housings
    • Interior parts
    • Bumpers & fenders
  • Aerospace
    • Aircraft braking systems
    • Thermal management
    • EMI/RFI shielding
    • Light weight composites

High Resolution TEM Image showing the stacked-cup structure of Pyrograf III

PYROGRAF NANOFIBERS UNIQUE PROPERTIES:

  • Electrical properties
    • High electrical conductivity in composites at low carbon nanofiber loading
    • Reduced cost for electrically conductive and dissipative compound Electrical conductivity without degrading mechanical properties
  • Mechanical properties
    • Increases mechanical strength of polyolefins up to four times
    • Increases impact strength in polar resins
    • Increases modulus of rubber compounds fourfold in high strain applications
  • Chemical properties
    • Chemical bonding to graphite planes to tailor composite properties
    • Reactive oxygen, sulfur and nitrogen sites on carbon nanofiber surfaces
    • Good interface between carbon nanofibers and polymer matrices
  • Thermal properties
    • Highest heat-transfer rates of all known materials
    • The most efficient thermal management composites
  • Adsorptive properties
    • Removal of heavy metals and radionucleides from water, wastewater and ground water
    • Highly adsorptive for organic materials

Contact Patrick Lake to discuss Pyrograf-III CNF and applications.

 

Contact Patrick D. Lake to learn more about Carbon Nanofibers.

Mr. Lake is a Chemical Engineer with over 15 years experience in the growth of vapor grown carbon fibers and carbon nanofibers, and the development of downstream products using these materials.