Naslov
Influence of the particle size on volume and properties of expanded graphite

Autori
Vrtodušić, Andrej ; Špehar, Goran ; Zlopaša, Jure ; Kurajica, Stanislav

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
XXI. Hrvatski skup kemičara i kemijskih inženjera / Novak, Predrag ; Pičuljan, Katarina ; Smolec, Sonja - Zagreb : Hrvatsko društvo kemijskih inženjera i tehnologa (HDKI) ; Hrvatsko kemijsko drustvo, 2009

ISBN
987-953-6894-38-3

Skup
XXI. Hrvatski skup kemičara i kemijskih inženjera

Mjesto i datum
Trogir, Hrvatska, 2009

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
Expanded graphite; Particle size; Intercallants

Sažetak
Expanded graphite has been applied widely as a kind of functional carbon material, used in gasketing, thermal insulation, adsorption, environment protection, catalyzing, electromagnetic interference shielding, vibration damping, etc. It is made by intercallation of natural flake graphite followed by thermal expansion. Intercalation is a process whereby an intercalant material is inserted between the graphene layers of a graphite crystal. Exfoliation, a huge unidirectional expansion of the starting intercalated flakes, occurs when the graphene layers are forced apart by the sudden decomposition and vaporization of the intercalated species by thermal shock. Along with production methodologies, such as intercalation process and heat treatment, raw material characteristics, especially particle size, strongly influence the properties of the final product. This report evaluates the influence of the particle size of the raw material on the expansion processes and consequently the properties of the exfoliated graphite. Natural crystalline flake graphite with large particle size distribution (between 80 and 425 mm) was divided in four size-range portions by sieving. Graphite was intercalated via perchloric acid, glacial acetic acid and potassium dichromate oxidation and intercalation procedure. Expansion was accomplished by thermal shock at 1000°C for 1 min. The prepared samples were characterized by means of exfoliation volume measurements, simultaneous differential thermal analysis and thermogravimetry, X-ray diffraction, Fourier transform infrared spectroscopy, BET measurements and scanning electron microscopy. X-ray diffraction patterns and Fourier-transformed infra red spectroscopy confirmed that the intercallant molecules had entered into the graphite layers. Faint endopeak, corresponding to the loss of intercallants has been observed at DTA curve of intercalated graphite. At the same temperature interval a weight loss occurred. It has been determined that a 315-425 mm fraction showed the greatest expansion volume of 86 cm3g-1. BET measurements of the 315-425 mm fraction of expanded graphite yielded specific surface area of 36 m2g-1. Scanning electron microscope images showed that the structure of expanded graphite is composed of worm-like particles with large pores.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

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