Polymer-graphene nanocomposites

Patent metadata

Field	Value
Publication number	US-9790334-B2
Application number	US-201414776022-A
Country	US
Kind code	B2
Filing date	Mar 14, 2014
Priority date	Mar 15, 2013
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

Provided herein is technology relating to polymer-graphene nanocomposites and particularly, but not exclusively, to methods for producing polymer-graphene nanocomposites using master batches comprising graphene and a polymer or polymer precursor. The resulting polymer-graphene nanocomposites comprise a high degree of exfoliation and dispersion of graphene nanoplatelets within the polymer matrix.

First claim

We claim:

1. A master batch composition for making a polymer nanocomposite, the master batch composition comprising a polymer, wherein the polymer is a poly(vinyl lactam), a polyacrylamide, a thermoplastic polymer, thermoset polymer, polyethylene polymer, polypropylene polymer, polycarbonate polymer, unsaturated polyester, polyvinylchloride, or epoxy vinyl ester, or epoxy and at least 20% by weight exfoliated graphene.

2. The master batch composition of claim 1 comprising graphene and a poly(vinylpyrrolidone) in a weight ratio of 1:1 to 1:4.

3. The master batch composition of claim 1 comprising graphene and a thermoplastic polymer in a weight ratio of 1:1 to 1:4.

4. The master batch composition of claim 1 wherein the average thickness of the graphene is less than 10 atomic layers, a minimum of 5% of the graphene is single atomic layer graphene, and the oxygen content of the graphene is less than 1%.

5. The master batch composition of claim 1 wherein less than 10% of the graphene nanoplatelets have a maximum diameter of less than 0.5 microns.

6. The master batch composition of claim 1 comprising a poly(vinylpyrrolidone) that has a number average molecular weight of less than or equal to approximately 10,000 u.

7. A method of making a master batch composition for producing a polymer nanocomposite, the method comprising:
a) mixing a slurry of graphene, wherein the slurry of graphene is produced by:
i) treating graphite in an N-alkyl-pyrrolidone to produce solvent exfoliated graphene in the N-alkyl-pyrrolidone;
ii) removing most of the N-alkyl-pyrrolidone to produce a concentrated solution or dispersion of graphene in the N-alkyl-pyrrolidone; and
iii) adding a solvent to the graphene in N-alkyl-pyrrolidone to produce the slurry of graphene in the solvent system in a solvent system with a polymer; and

b) removing the solvent system to produce a master batch comprising from 20% to 60% exfoliated graphene.

8. The method of claim 7 wherein the mixing is high shear mixing.

9. The method of claim 7 wherein the polymer is a polyvinyl lactam or a thermoplastic polymer.

10. The method of claim 7 wherein the solvent is xylenes or methanol.

11. The method of claim 7 wherein the concentrated solution or dispersion of graphene in the N-alkyl-pyrrolidone comprises 2% to 8% graphene.

12. The method of claim 7 comprising filtration to remove the N-alkyl-pyrrolidone.

13. The method of claim 7 wherein the solvent system comprises 2% to 30% N-alkyl-pyrrolidone and 70% to 98% solvent.

14. A method of making a graphene/thermoplastic master batch consisting of the steps:
a) concentrating a solution or stable dispersion of exfoliated graphene above the solubility and stable dispersion limit of the exfoliated graphene;
b) dissolving a thermoplastic polymer in the graphene/solvent slurry in a ratio of 1:1 to 1:5 graphene to polymer; and
c) removing the solvent with continuous mixing to isolate the resultant graphene/polymer master batch as a solid.

15. A method of making a graphene/polymer master batch, the method comprising:
a) exfoliating graphene in a polymerizable solvent, wherein the polymerizable solvent is N-vinyl pyrrolidone or N,N-dimethyl acrylamide to provide a dispersion of exfoliated graphene in the polymerizable solvent;
b) polymerizing the polymerizable solvent to produce a graphene/polymer master batch.

Assignees

• Reliance Ind Ltd

Inventors

• Clauss Allen David
• Pan Guiquan
• Wietfeldt Nicholas Richard
• Hall Matthew Clayton
• Taft David D

Classifications

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C08J2339/06

  Homopolymers or copolymers of N-vinyl-pyrrolidones · CPC title

• C08J5/005

  Reinforced macromolecular compounds with nanosized materials, e.g. nanoparticles, nanofibres, nanotubes, nanowires, nanorods or nanolayered materials · CPC title

• C08J2377/06

  Polyamides derived from polyamines and polycarboxylic acids (C08J2377/10 takes precedence) · CPC title

• C08J3/2053

  the additives only being premixed with a liquid phase · CPC title