Design of aluminamonoliths by emulsion-gel casting: Understanding the monolith structure from a rheological approach

authors	Nayak, N; Vitorino, N; Frade, JR; Kovalevsky, AV; Alves, VD; Crespo, JG; Portugal, CAM
nationality	International
journal	MATERIALS & DESIGN
author keywords	Alumina monoliths; Emulsion-gel casting; Viscoelastic properties; Porous structure; Chromatography
keywords	CELLULAR CERAMICS; ALUMINA; SUSPENSIONS; FOAMS; GELATION; AGAROSE
abstract	Multimodal porous cellular alumina structures (monoliths) were prepared by an emulsion-gel casting technique using eco-friendly and inexpensive lipids such as corn oil, castor oil, margarine and their mixtures as the dispersed phase. The monoliths obtained showed good mechanical stability, exhibiting compressive strengths in the range of 8-50 N.mm(-2). Mercury intrusion porosimetry analysis showed that the monoliths produced presented porosities ranging from 28% to 60% and average pore sizes within 0.2-3.2 mu m. The formation of the porous networks was interpreted based on combined droplet coalescence, flocculation and Ostwald ripening effects. The presence of such effects along the emulsion storage time led to changes in their viscoelastic and morphological properties, which were found to correlate with structural descriptors of monoliths after sintering (e.g. average pore sizes and porosity). These correlations open up the possibility to anticipate the final structure of the monoliths and adjust emulsion-gel conditions to produce customized cellular structures with fine-tuned porosities and pore sizes, envisaging their application in membrane processes or chromatography. (C) 2018 Published by Elsevier Ltd.
publisher	ELSEVIER SCI LTD
issn	0264-1275
year published	2018
volume	157
beginning page	119
ending page	129
digital object identifier (doi)	10.1016/j.matdes.2018.07.017
web of science category	Materials Science, Multidisciplinary
subject category	Materials Science
unique article identifier	WOS:000443826600012