Surface hydrophobization of bacterial and vegetable cellulose fibers using ionic liquids as solvent media and catalysts

The surface hydrophobization through heterogeneous chemical modification of bacterial (and vegetable) cellulose fibers with several anhydrides (acetic, butyric, hexanoic and alkenyl succinic anhydrides) and hexanoyl chloride suspended in an ionic liquid, tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl) imide, [TDTHP][NTf(2)], was studied. Furthermore, in the reaction with hexanoyl chloride, another ionic liquid, N-hexyl-4-(dimethylamino)pyridinium bis(trifluoromethylsulfonyl) imide, [C(6)N(CH(3))(2)py][NTf(2)], was used instead of common organic bases as catalyst and to trap the released HCl. The analysis of the ensuing modified fibers by FTIR, XRD and SEM clearly showed that the esterification reactions occurred essentially at the fibers' outmost layers, not affecting their ultrastructure. The degree of substitution (DS) of the ensuing esterified fibers ranged from less than 0.002 to 0.41; and in all instances, the fibers' surface acquired a high hydrophobicity. This novel approach constitutes an important strategy in the preparation of modified fibers under greener conditions relaying in the use of non-volatile solvents.FCT - SFRH/BD/72830/2010SFRH/BPD/41781/2007PTDC/QUI/68472/2006PTDC/QUI/72903/200

El vestuario y el calzado para bailar, una mirada con perspectiva histórica sobre algunos elementos que definen la danza académica teatral

For centuries, humans have expressed artistically, showing that communication that is not part of the universe of words can be profound and can contribute to human development. One of those artistic expressions is dance, which is conveyed through body language. The academic theatre dance known as ballet is one of its manifestations, and it has its roots in Europe, where technical and expressive characteristics were created that are still in effect today. This article wishes to review some aspects that have been decisive for dance and will refer to wardrobe and footwear as constituent elements of theatre expression, emphasizing that the work of art will always be embedded in its historical context.Durante siglos, la humanidad se ha manifestado artísticamente, mostrando que la comunicación que no pertenece al universo de la palabra puede ser profunda y contribuir al desarrollo del ser humano. Entre sus expresiones artísticas está la danza, la cual se desarrolla mediante el lenguaje corporal. La danza académica teatral, conocida como ballet, es una de sus manifestaciones, y tiene sus raíces en Europa, en donde se plasmaron características técnicas y expresivas que siguen vigentes hasta nuestros días. Este artículo revisa aspectos que han sido determinantes en la danza y se refiere al vestuario y al calzado como elementos constitutivos de la expresión escénica, enfatizando que la obra de arte siempre estará encarnada en su contexto histórico

Cationic copolymerization of styrene with an isocyanate-bearing homologue

International audienc

The surface chemical modification of cellulosic fibres in view of their use in composite materials

International audienc

Surface energy and wettability of modified cellulosic fibres to integrate composite materials

International audienc

Interfacial properties of regenerated cellulose fiber/polystyrene composite materials. Effect of the coupling agents structure on the micromechanical behavior

International audienc