Conductive nanocomposite having a dual temperature coefficient of resistance and a method of preparing

Patent metadata

Field	Value
Publication number	US-10982082-B1
Application number	US-202016995336-A
Country	US
Kind code	B1
Filing date	Aug 17, 2020
Priority date	Aug 17, 2020
Publication date	Apr 20, 2021
Grant date	Apr 20, 2021

Abstract

A conductive nanocomposite which contains a mixed polymer matrix which contains a rubber and a polyether, carbon nanoparticles, and transition metal nanoparticles. The conductive nanocomposite has a nonlinear relationship between resistivity and temperature characterized by an exponential increase reaching a peak resistivity followed by an exponential decrease as temperature increases. Also disclosed is a method of forming the conductive nanocomposite involving mixing the components, aging, and pressing. The conductive nanocomposite forms a component of a heater that is self-regulating as a result of the nonlinear relationship between resistivity and temperature of the conductive nanocomposite. The nanocomposite also forms a component of a thermistor.

First claim

The invention claimed is:

1. A conductive nanocomposite comprising:
a mixed polymer matrix comprising an isobutylene isoprene rubber and a polyethylene oxide,
graphene nanoparticles in the form of nanosheets in an amount of 0.1 to 5 wt % based on the total weight of the conductive nanocomposite, and
carbonyl iron metal nanoparticles having a mean particle diameter of 8 nm in an amount of 1-4 wt % based on the total weight of the conductive nanocomposite,
wherein the conductive nanocomposite has a nonlinear relationship between resistivity and temperature in the region of 25 to 180° C. characterized by an exponential increase reaching a peak resistivity followed by an exponential decrease, and
wherein the conductive nanocomposite has a peak resistivity of 2500 to 18000 ohm·cm at a temperature of 100 to 180° C.

2. The conductive nanocomposite of claim 1 , wherein the graphene nanosheets are in the form of particles having a mean particle size of 0.33 to 50 nm.

3. The conductive nanocomposite of claim 1 , which has a positive temperature coefficient in a first temperature region and a negative temperature coefficient in a second temperature region.

4. A heater comprising the conductive nanocomposite of claim 1 sandwiched between metal electrodes.

5. The heater of claim 4 , which has a heating exchange coefficient by convection of 1 to 100 Wm −2 K −1 .

6. The heater of claim 1 , which has a heating exchange coefficient by radiation of 0.5 to 50 Wm −2 K −1 .

7. The heater of claim 1 , which reaches a maximum working temperature of 40 to 130° C. when subjected to a working power of 0.11 to 0.21 W/cm 3 .

8. A thermistor comprising the conductive nanocomposite of claim 1 .

9. The thermistor of claim 8 , wherein the thermistor has a positive temperature coefficient in a first thermistor temperature region and a negative temperature coefficient in a second thermistor temperature region.

Assignees

• Univ King Abdulaziz

Inventors

• Al-Ghamdi Ahmed A
• Al-Sehemi Abdullah G
• Kalam Abul
• Dere Aysegul
• Yakuphanoglu Fahrettin

Classifications

• H01C17/06553

  composed of a combination of metals and oxides · CPC title

• H01C17/0652

  containing carbon or carbides · CPC title

• H01C7/042

  mainly consisting of inorganic non-metallic substances (H01C7/041 takes precedence) · CPC title

• H01C7/027

  consisting of conducting or semi-conducting material dispersed in a non-conductive organic material · CPC title

• H01C7/008

  Thermistors (H01C7/02 - H01C7/06 take precedence) · CPC title