# US 8,784,695 B2 · Method for manufacturing polyurethane nanocomposite comprising expanded graphite and composition thereof

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- Number: US 8,784,695 B2
- Document ID: US8784695B2
- Status: Granted
- Kind: B2
- Application number: 13/174,571
- Filed: 2011-06-30
- Published: 2013-01-03
- Granted: 2014-07-22
- Earliest claimed: 2011-06-30
- Assignees: G&Cs Co., Ltd
- Applicants: Suk-Hong Choi; Sang-Hee Park
- Inventors: Suk-Hong Choi; Sang-Hee Park
- Web page: https://patentgrep.com/patent/US8784695B2

## CPC

- C08L 75/04: Polyurethanes
- C08G 18/12: using two or more compounds having active hydrogen in the first polymerisation step
- C08G 18/44: Polycarbonates
- C08G 18/664: {with compounds of group C08G18/3203}
- H01B 1/24: the conductive material comprising carbon-silicon compounds, carbon or silicon
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})

## Abstract

Disclosed herein is a method of manufacturing a nanocomposite using expanded graphite. The method is characterized in that monomers are formed into a polymer between the plate-shaped layers of the expanded graphite, and the polymer is intercalated therebetween, so that the plate-shaped layers of the expanded graphite are completely exfoliated or are formed into graphene, with the result that the expanded graphite is completely dispersed in a polymer matrix. The nanocomposite manufactured by this method has excellent electrical conductivity and thermal conductivity because the expanded graphite is uniformly dispersed in this nanocomposite.

## Claims

### Claim 1

A method of manufacturing a nanocomposite, comprising the steps of:
dissolving expanded graphite in an organic solvent to prepare an expanded graphite-dispersed solution;
mixing a polyol and a diol with a catalyst and reacting the mixture with a diisocyanate to form a prepolymer;
introducing the expanded graphite-dispersed solution into the prepolymer; and
introducing a chain extender into the prepolymer.

### Claim 2 (depends on 1)

The method of manufacturing a nanocomposite according to claim 1, wherein the organic solvent is at least one selected from the group consisting of dimethylformamide (DMF), methyl ethyl ketone (MEK), toluene, and acetone.

### Claim 3 (depends on 2)

The method of manufacturing a nanocomposite according to claim 2, wherein the organic solvent further includes a dispersant.

### Claim 4 (depends on 3)

The method of manufacturing a nanocomposite according to claim 3, further comprising the step of ultrasonic-treating the expanded graphite-dispersed solution.

### Claim 5 (depends on 1)

The method of manufacturing a nanocomposite according to claim 1,
wherein the polyol is at least one selected from the group consisting of polyester polyol, polycarbonate diol, polypropylene glycol, polyethylene glycol, poly(tetramethylene)glycol, and polycarprolactone glycol, and
the diol is at least one selected from the group consisting of 1,4-butanediol, ethylene glycol, diethylene glycol, and 1,6-hexanediol.

### Claim 6 (depends on 1)

The method of manufacturing a nanocomposite according to claim 1, wherein the chain extender is at least one selected from the group consisting of ethylene diamine, ethylene triamine, 1,4-butanediol, ethylene glycol, diethylene glycol, and 1,6-hexanediol.

### Claim 7 (depends on 1)

The method of manufacturing a nanocomposite according to claim 1, wherein the prepolymer is formed at 75˜85° C.

### Claim 8 (depends on 1)

The method of manufacturing a nanocomposite according to claim 1, wherein the expanded graphite-dispersed solution is introduced into the prepolymer while maintaining the viscosity of the prepolymer at 100,000˜150,000cps.

### Claim 9 (depends on 1)

The method of manufacturing a nanocomposite according to claim 1, wherein the nanocomposite comprises the expanded graphite in an amount of 3˜7 wt %.

### Claim 10 (depends on 9)

The method of manufacturing a nanocomposite according to claim 9, wherein the nanocomposite has electrical resistance of 1.3×102˜1.3×107 (Ω/sq).

### Claim 11 (depends on 9)

The method of manufacturing a nanocomposite according to claim 9, wherein the nanocomposite has thermal conductivity of 0.96˜2.55 W/m0K in a horizontal direction, and has thermal conductivity of 0.25˜0.57 W/m0K in a vertical direction.