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187 results on '"Boufi, S."'

46. Biocomposites based on Alfa fibers and starch-based biopolymer.

Author

Belhassen, R., Boufi, S., Vilaseca, F., López, J. P., Méndez, J. A., Franco, E., Pèlach, M. A., and Mutjé, P.

Subjects
CELLULOSE fibers, STRENGTH of materials, BIOPOLYMERS, THERMAL properties, THERMAL analysis
Abstract

Biocomposite materials based on Alfa cellulose fibers (esparto grass plant) as reinforcing element and starch-based biopolymer matrix were prepared and characterized in terms of mechanical performance, thermal properties, and water absorbance behavior. The fibers and the matrix were first mixed in the melted state under mechanical shearing using a plastograph and the obtained composites were molded by injection process. The tensile mechanical analysis showed a linear increase of the composite flexural and tensile modulus upon increasing the fiber content, together with a sharp decrease of the elongation at break. The fibers′ incorporation into the biopolymer matrix brings about an enhancement in the mechanical strength and the impact strength of the composite. Dynamic mechanical thermal analysis (DMTA) investigation showed two relaxations occurring at about −30 and 35°C. The addition of Alfa fibers enhanced the storage modulus E′ before and after T α, which is consistent with the reinforcing effect of Alfa cellulose fibers. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Published
2009
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47. Adsorption of a Cationic Surfactant onto Cellulosic Fibers I. Surface Charge Effects

Author

Alila, S., Boufi, S., Belgacem, M. N., and Beneventi, D.

Abstract

The adsorption of four cationic surfactants with different alkyl chain lengths on cellulose substrates was investigated. Cellulose fibers were used as model substrates, and primary alcohol groups of cellulose glycosyl units were oxidized into carboxylic groups to obtain substrates with different surface charges. The amount of surfactant adsorbed on the fiber surface, the fiber ζ-potential, and the amount of surfactant counterions (Cl-) released into solution were measured as a function of the surfactant bulk concentration, its molecular structure, the substrate surface charge, and the ionic strength. The contribution of each of these parameters to the shape of the adsorption isotherms was used to verify if surfactant adsorption and self-assembly models usually used to describe the behavior of surfactant/oxide systems can be applied, and with which limitations, to describe cationic surfactant adsorption onto oppositely charged cellulose substrates.

Published
2005

48. Interaction of Silane Coupling Agents with Cellulose

Author

Abdelmouleh, M., Boufi, S., Salah, A. ben, Belgacem, M. N., and Gandini, A.

Abstract

The adsorption of several prehydrolyzed alkoxysilanes onto the surface of cellulosic fibers in ethanol/water mixtures has been studied quantitatively. The corresponding isotherms show the formation of a monolayer followed by further adsorption. The nature of the fourth substituent on the silane plays a specific role on the features of this association. Whereas at room temperature only dispersive and polar attractive interactions occur, heating above 100 °C produces condensation reactions resulting in covalent bonding between the substrate and the silane forming the monolayer. As a result of this investigation, the possibility of calling upon this surface modification in order to compatibilize cellulosic fibers with polyolefinic matrixes for the elaboration of composite materials seems to be a promising strategy.

Published
2002
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