title: Versatile gas-phase reactions for surface to bulk esterification of cellulose microfibrils aerogels.
abstract: Aqueous suspensions of microfibrillated cellulose obtained by a high pressure homogenization process were freeze-dried after solvent exchange into tert-butanol. The resulting aerogels, which displayed a remarkable open morphology with a surface area reaching 100 m(2)/g, were subjected to a gas-phase esterification with palmitoyl chloride. Under these conditions, variations of the reaction temperature from 100 to 200 °C, of the reaction time from 0.5 to 2 h, and of the initial quantity of reagent, led to the preparation of a library of cellulose palmitates with DS varying from zero to 2.36. These products were characterized by gravimetry, FTIR, and (13)C solid-state NMR spectroscopy. Of special interest were the cellulose palmitate samples of low DS in the range of 0.1-0.4, which corresponded to hydrophobic cellulose microfibrils exclusively esterified at their surface while keeping intact their inner structure.
authors.affiliation: Centre de Recherches sur les Macromolécules Végétales, CERMAV-CNRS, BP 53, F-38041 Grenoble Cedex 9, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Fumagalli
authors.forename: Djamila
authors.initials: D
authors.lastname: Ouhab
authors.forename: Sonia Molina
authors.initials: SM
authors.lastname: Boisseau
authors.forename: Laurent
authors.initials: L
authors.lastname: Heux
mesh_terms: D002482:Cellulose / Q000737:chemistry* / Q000648:ultrastructure; D004951:Esterification; D005740:Gases / Q000737:chemistry; D005782:Gels; D057927:Hydrophobic and Hydrophilic Interactions; D054878:Lipoylation; D009682:Magnetic Resonance Spectroscopy; D020894:Microfibrils / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D005740:Gases; D005782:Gels; D002482:Cellulose