Elastomer composites with high dielectric constant
Elastomer compositions with high dielectric constants are disclosed. Embodiments of the disclosure include a high dielectric constant (high-K) elastomeric composition comprising an elastomer, carbon black (CB), and organoclay (OC). The composition is not dependent on any raw material with inherent high-k or any metal oxide type material that changes conductivity with applied voltages. The composition instead uses distributed electric fields and polarizability with carbon black and organoclays. This allows for a high-k material through polarizability with limited large-scale electron sharing.
1. A polymer composition comprising:
a polymer,
an organically modified clay, and
carbon black particles,
wherein particles of the organically modified clay are larger than the carbon black particles,
wherein the polymer composition has a dielectric constant greater than 5 and less than 1000 and a dielectric loss (tan delta) of less than 10%, and
wherein the dielectric constant varies substantially linearly with temperature in a range from 20° C. to 100° C.
2. The polymer composition of claim 1 , wherein the dielectric constant varies inversely with temperature in the range from 20° C. to 100° C.
3. The polymer composition of claim 1 , wherein the organically modified clay has a platy shape.
4. The polymer composition of claim 1 , wherein the organically modified clay is a high aspect ratio dielectric filler.
5. The polymer composition of claim 1 , wherein the organically modified clay and the carbon black particles form a structured composite in which the organically modified clay separates particles of the carbon black particles.
6. The polymer composition of claim 1 , wherein the polymer is an elastomer.
7. The polymer composition of claim 1 , wherein the polymer comprises 30-55% by weight of the polymer composition.
8. The polymer composition of claim 1 , wherein the carbon black particles comprise 5-40% by weight of the polymer composition.
9. The polymer composition of claim 1 , wherein the organically modified clay comprises 1-7% by weight of the composition.
10. The polymer composition of claim 1 , wherein the organically modified clay is an ammonia treated montmorillonite.
11. The polymer composition of claim 1 , wherein the carbon black particles have a particle size range from 10-900 nanometers.
12. The polymer composition of claim 1 , further comprising an inorganic filler.
13. The polymer composition of claim 12 , wherein the inorganic filler comprises 10-25% by weight of the composition.
14. The polymer composition of claim 12 , wherein the inorganic filler is one or more of (Nb,In,)TiO 2 , rutile-TiO 2 , SiO 2 , ZnO, tin oxide, lead oxide, iron oxide, and calcium oxide.
15. An electrical stress grading apparatus comprising a polymer composition, the polymer composition comprising:
a polymer,
an organically modified clay, and
carbon black particles,
wherein particles of the organically modified clay are larger than the carbon black particles,
wherein the polymer composition has a dielectric constant greater than 5 and less than 6000 and a dielectric loss of less than 10%, and
wherein the dielectric constant varies substantially linearly with temperature in a range from 20° C. to 100° C.
16. The electric stress grading apparatus of claim 15 , wherein the dielectric constant varies inversely with temperature in the range from 20° C. to 100° C.
17. The electrical stress grading apparatus of claim 15 , wherein the dielectric constant of the electrical stress grading apparatus is 5-50.
18. The electric stress grading apparatus of claim 15 , wherein the carbon black particles have a particle size range from 10-900 nanometers.
19. The electric stress grading apparatus of claim 15 , wherein the polymer composition further comprises an inorganic filler.
20. The electric stress grading apparatus of claim 15 , wherein the organically modified clay and the carbon black particles form a structured composite in which the organically modified clay separates particles of the carbon black particles.