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https://hdl.handle.net/1822/1614
Título: | Characterisation of cellulose surface free energy |
Autor(es): | Dourado, Fernando Gama, F. M. Chibowski, E. Mota, M. |
Palavras-chave: | Cellulose Particle size Crystallinity Surface free energy components Hydrophobicity |
Data: | 1998 |
Editora: | VSP |
Revista: | Journal of Adhesion Science and Technology |
Citação: | "Journal of adhesion science and technology". ISSN 0169-4243. 12:10 (1998) 1081-1090. |
Resumo(s): | The thin-layer wicking technique was used to determine the surface free energy components and the surface character of three celluloses (Sigmacell 101, Sigmacell 20, and Avicel 101), using an appropriate form of the Washburn equation. For this purpose, the penetration rates of probe liquids into thin porous layers of the celluloses deposited onto horizontal glass plates were measured. It was found that the wicking was a reproducible process and that the thin-layer wicking technique could be used for the determination of the celluloses' surface free energy components. The size of the cellulose particles was characterized with the Galai CIS-100 system and their crystallinity was measured by X-ray diffraction. The three celluloses have high apolar (ys LW = 50-56 mJ/m²) and electron donor ys- = 42-45 mJ/m²) components, while the electron acceptor component (ys+) is pratically zero. The free energy interactions of cellulose/water/cellulose calculated from the components are positive, regardless of the cellulose crystallinity. This would mean that the cellulose surfaces have a hydrophilic character. However, the work of spreading of water has a small negative value (3-9 mJ/m²), indicating that the surfaces are slightly hydrophobic. It is believed that the work of spreading characterizes better the hydrophobicity of the surface than the free energy of particle/water/particle interaction, because in the latter case, no electrostatic repulsion is taken into account in the calculations. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/1614 |
DOI: | 10.1163/156856198X00740 |
ISSN: | 0169-4243 1568-5616 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | CEB - Publicações em Revistas/Séries Internacionais / Publications in International Journals/Series |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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1998-08[1].pdf | 469,49 kB | Adobe PDF | Ver/Abrir |