abstract
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][NTf2], was studied. Furthermore, in the reaction with hexanoyl chloride, another ionic liquid, N-hexyl-4-(dimethylamino)pyridinium bis(trifluoromethylsulfonyl) imide, [C6N(CH3)(2)py][NTf2], 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.
keywords
NANOFIBRILLATED CELLULOSE; BARRIER PROPERTIES; FATTY-ACIDS; ACETYLATION; MEMBRANES; BEHAVIOR; WATER
subject category
Chemistry; Science & Technology - Other Topics
authors
Tome, LC; Freire, MG; Rebelo, LPN; Silvestre, AJD; Neto, CP; Marrucho, IM; Freire, CSR
our authors
Armando Jorge Domingues Silvestre
Full professor
Carlos Pascoal Neto
Raiz Director
Carmen Sofia da Rocha Freire Barros
Coordinating Researcher
Isabel Maria Delgado Jana Marrucho Ferreira
Full professor
Liliana C. Tomé
PhD Student
Mara Guadalupe Freire Martins
Coordinating ResearcherGroups
G4 - Renewable Materials and Circular Economy
G5 - Biomimetic, Biological and Living Materials
Projects
acknowledgements
FCT (Fundacao para a Ciencia e Tecnologia) is acknowledged for Liliana C. Tome (PhD research grant SFRH/BD/72830/2010) and Mara G. Freire (Postdoctoral research grant SFRH/BPD/41781/2007), and for financial support through the Projects PTDC/QUI/68472/2006 and PTDC/QUI/72903/2006. The authors also acknowledge Cytec Industries for kindly providing [TDTHP][NTf