Hossain, Muhammad Mohsin Hahn, Jae Ryang Ku, Bon-Cheol 2024-01-20T09:30:54Z 2024-01-20T09:30:54Z 2021-09-05 2014-07-20 0253-2964 https://pubs.kist.re.kr/handle/201004/126583 A simple method for exfoliating pristine graphite to yield mono-, bi-, and multi-layers of graphene sheets as a highly concentrated (5.25 mg/mL) and yielded solution in an organic solvent was developed. Pre-thermal treatment of pristine graphite at 900 degrees C in a sealed stainless steel bath under high pressures, followed by sonication in 1-methyl-2-pyrrolidinone solvent at elevated temperatures, produced a homogeneous, well-dispersed, and non-oxidized graphene solution with a low defect density. The electrical conductivities of the graphene sheets were very high, up to 848 S/cm. These graphene sheets were used to fabricate graphene-polyimide nanocomposites, which displayed a higher electrical conductivity (1.37 S/m) with an improved tensile strength (95 MPa). The synthesized graphene sheets and nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. English WILEY-V C H VERLAG GMBH LIQUID-PHASE EXFOLIATION AQUEOUS DISPERSIONS LARGE-AREA FILMS OXIDE Synthesis of Highly Dispersed and Conductive Graphene Sheets by Exfoliation of Preheated Graphite in a Sealed Bath and its Applications to Polyimide Nanocomposites Article 10.5012/bkcs.2014.35.7.2049 1 BULLETIN OF THE KOREAN CHEMICAL SOCIETY, v.35, no.7, pp.2049 - 2056 BULLETIN OF THE KOREAN CHEMICAL SOCIETY 35 7 2049 2056 scie scopus kci ART001891185 000339642700026 2-s2.0-84907227475 Chemistry, Multidisciplinary Chemistry Article LIQUID-PHASE EXFOLIATION AQUEOUS DISPERSIONS LARGE-AREA FILMS OXIDE Graphene sheets Thermal exfoliation Polyimide nanocomposites Electrical conductivity Tensile strength