resumo
This work describes the preparation of cellular graphite/paraffin composites by a facile emulsification-based method. Graphite is readily dispersed in starch aqueous suspension and this readily emulsifies with liquid paraffin above its melting temperature. The resulting emulsion remains stable to allow selective drying of the aqueous suspension, yielding a cellular graphite network consolidated by starch and filled in situ by paraffin. Self organization of the cellular graphite skeleton was easily revealed by volatilization of paraffin. These cellular graphite/paraffin composites show remarkable enhancement of thermal conductivity, in the range 5-8 W m(-1) K-1, and electrical conductivity up to about 6S m(-1). A Taguchi plan was used to analyse the effects of stirring rate, stirring time, starch content and graphite suspension to paraffin volumetric ratio on average cellular cavity size, thermal conductivity and electrical conductivity. This analysis provides trends for further optimization. (C) 2012 Elsevier B.V. All rights reserved.
palavras-chave
PHASE-CHANGE MATERIALS; FORM-STABLE PCM; CONDUCTIVITY ENHANCEMENT; ENERGY-STORAGE; PARAFFIN WAX; STARCH
categoria
Materials Science; Physics
autores
Vitorino, N; Abrantes, JCC; Frade, JR
nossos autores
João Carlos de Castro Abrantes
Professor Adjunto
Jorge Ribeiro Frade
Professor(a) Jubilado(a)
Nuno Miguel Dias Vitorino
Bolseiro de pós-Doutoramentoagradecimentos
This work was supported by Fundacao para a Ciencia e a Tecnologia-FCT, FEDER. One of the authors was supported by a FCT PhD grant SFRH/BD/62598/2009. The SEM facility was funded by FEDER Funds through QREN-Aviso SAIECT-IEC/2/2010, Operacao NORTE-07-0162-FEDER-000050.