resumo
Cellophane (regenerated cellulose) membranes with tailored properties regarding hydrophobic character and barrier effects were prepared by their controlled heterogeneous esterification with two fatty acid derivatives (hexanoyl and dodecanoyl chlorides) The characterization of the modified membranes was performed by FUR spectroscopy X-ray diffraction and thermogravimetry confirming the success of the heterogeneous modification reaction while keeping cellophane membranes structural properties Contact angle measurements clearly confirm the enhanced hydrophobic character displayed by the modified cellophane membranes The evaluation of their barrier properties was carried out by determining the permeability towards water vapor at different relative humidities and the permeability towards nitrogen oxygen and carbon dioxide using the time-lag method in both wet and dry states A decrease in both the water permeation and the permeability towards these gases in the wet state was observed for the modified membranes No significant differences in behavior were found between the membranes prepared with hexanoyl and dodecanoyl chloride regarding hydrophobicity but the different lengths of the chain allowed a fine tune of the permeability The obtained cellophane membranes are a good example of the development of new bio-based materials with improved surface and barrier properties (C) 2010 Elsevier Ltd All rights reserved
palavras-chave
WATER-VAPOR PERMEABILITY; CELLULOSE FIBERS; MECHANICAL-PROPERTIES; HYDROPHOBIC FILMS; GAS-PERMEABILITY; EDIBLE FILMS; PERMEATION; ESTERIFICATION; TRANSPORT; SORPTION
categoria
Chemistry; Polymer Science
autores
Tome, LC; Goncalves, CMB; Boaventura, M; Brandao, L; Mendes, AM; Silvestre, AJD; Neto, CP; Gandini, A; Freire, CSR; Marrucho, IM
nossos autores
Alessandro Gandini
Investigador
Armando Jorge Domingues Silvestre
Professor Catedrático
Carlos Pascoal Neto
Diretor do Raiz
Carmen Sofia da Rocha Freire Barros
Investigador Principal
Isabel Maria Delgado Jana Marrucho Ferreira
Professor Catedrático
Liliana C. Tomé
Estudante de doutoramentoagradecimentos
Liliana C Tome thanks the FCT (Fundacao para a Ciencia e a Tecnologia) for awarding a research grant (PTDC/QUI/68472/2006)