Topic: Low Cost Carbon Fiber and Composites Technology

Outlines:

UTSI Pitch (Green) Fibers

• High Speed, Melt Blown Spinning Process

• Continuous Mesophase Pitch Fibers abundant and cheap natural material  very high carbon yield UTSI Fiber spinning apparatus

UTSI Carbon Fibers

• Relatively fast thermal stabilization in air

• Low-temperature carbonization at 1050oC  

Carbon Fiber

Green Fiber

Stabilized Fiber

Carbon Fiber

UTSI Carbon Fibers Form

• UTSI carbon fiber is produced in tape or non-woven fabric (mat) with ~10 cm in width and ~ 0.5-1 cm thick.

• Fiber filaments are  continuous but are almost randomly oriented.

• The carbon fiber can be easily fabricated into non-woven mat (or paper) with polymer binders.

Typical UTSI carbon fiber form Continuous carbon fiber mat (paper) and chopped carbon fiber mat made from the UTSI carbon fiber and a polymeric binder

The pitch fibers have a high carbon yield for making carbon  fibers.

• The carbon yield is also depending on the level of stabilization of the green fibers Yields of fibers after stabilization and carbonization at lower (600oC) and higher (1050oC) temperatures

The diameter of pitch fibers and resulting carbon fibers decreased with increasing blowing flow rates.

• The carbon fiber diameter could be reduced to 7 to 20 m, if fibers were processed for higher level of stabilization. Diameter of carbon fibers vs blowing flow rate

Tensile strength and young's modulus increased with increasing the level of stabilization. However, too much higher level of stabilization will decrease strength and modulus.

• At 1050oC, tensile strength and modulus of the fiber (20 -10 m) can reach 500-1100 Mpa and 70-110 Gpa, respectively. When the carbonization temperature is up to 1500oC, the strength and modulus can be up to ~2.5 Gpa and ~200 Gpa

respectively

Polymer resins tested :

Epoxy resin

Vinyl ester

Phenolic resin

Hot Press :

Using pressure to control the fiber volume

Using temperatures to control resin infusion and curing

SEM images of carbon fiber composite plate showing that the fibers were almost randomly aligned in the composites

Features:

• Relatively high strength (mesophase CF as reinforcement is hard to be activated)

• Higher surface area (from phenolic– based carbon matrix after activation)

• Various shapes and formation as a whole material

• Contact efficiency is superior to fibrous and granular activated carbons.

• Relatively high electrical conductivity (from long mesophase pitch-based carbon fibers)

• Flexibility in engineering design

UTSI

Mesophase

Pitch-based

Carbon Fiber

Carbonized Composites

UTSI Activated Carbon

Composites

Carbonization

Activation

Phenolic

Resin

Solution

CF / phenolic Composites

(can be molded to different form)

Fabrication

Potential Applications:

• Used as adsorbents/carbon membranes for water and air purification

• Catalyst and catalyst supporter

• Electrode materials for battery

• Combination of structural and functional Materials

Summary

• Pitch is produced from petroleum or coal

• Melt-blow spun, solvated mesophase pitch-based carbon fibers have ~ 75 wt% carbon yield at 1050oC.

• The tensile properties of carbon fibers are strongly influenced by stabilization level and carbonization temperatures.

• The form of the carbon fiber is different from that of typical commercial products and is as non-woven fabric. All fiber filaments are continuous with controlled orientation.

• Using such carbon fibers as reinforcement, the flexural properties of the composite did not display much difference at 0o and 90o of fiber mat direction

• Surface activation results in excellent filtration materials.