Thermosets containing carbon nanotubes by extrusion
View Patent ↗Methods of preparing conductive thermoset precursors containing carbon nanotubes is provided. Also provided is a method of preparing conductive thermosets containing carbon nanotubes. The carbon nanotubes may in individual form or in the form of aggregates having a macromorpology resembling the shape of a cotton candy, bird nest, combed yarn or open net. Preferred multiwalled carbon nanotubes have diameters no greater than 1 micron and preferred single walled carbon nanotubes have diameters less than 5 nm. Carbon nanotubes may be adequately dispersed in a thermoset precursor by using a extrusion process generally reserved for thermoplastics. The thermoset precursor may be a precursor for epoxy, phenolic, polyimide, urethane, polyester, vinyl ester or silicone. A preferred thermoset precursor is a bisphenol A derivative.
1. A method of preparing a thermoset precursor comprising:
providing a thermoset precursor having a viscosity greater than 15 poise; and
extruding carbon nanotubes with said thermoset precursor.
2. The method of claim 1 , wherein said carbon nanotubes have a diameter less than 1 micron.
3. The method of claim 1 , wherein said thermoset precursor is an epoxy precursor, phenolic precursor, polyimide precursor, urethane precursor, polyester precursor, vinyl ester precursor or silicone precursor.
4. The method of claim 1 , wherein said thermoset precursor has a viscosity of 20 to 600 poise.
5. The method of claim 1 , wherein said carbon nanotubes are present in an amount of 0.5 to 40% by weight.
6. The method of claim 1 , wherein said extruding comprises use of a twin screw extruder.
7. The method of claim 1 , further comprising milling said thermoset precursor.
8. The method of claim 7 , wherein said milling comprises use of a three roll mill.
9. A thermoset precursor formed by the method of claim 1 .
10. A thermoset formed with the thermoset precursor of claim 9 .
11. The thermoset of claim 10 , wherein said thermoset has a resistivity of less than 10 11 ohm-cm.