title: Controlled Silylation of Nanofibrillated Cellulose in Water: Reinforcement of a Model Polydimethylsiloxane Network.
abstract: A comparative approach for the surface silylation of nanofibrillated cellulose (NFC) in water is proposed through an environmentally friendly sol-gel route based on alkoxysilanes. NFC suspensions were freeze-dried under controlled conditions in the presence of methyltrimethoxysilane used as a model alkoxysilane. Two different protocols that involve different pH values (0.4 and 4) and post-treatment procedures were investigated and compared. Protocol 1 led to a network of nanofibrils in which polysiloxane particles were dispersed, and protocol 2 produced a scaffold of cellulosic fibrils coated by a polysiloxane layer bonded firmly to the cellulosic substrate. Different from protocol 1, protocol 2 imparted the cellulosic material with hydrophobic properties and improved its thermal stability. Moreover, if 1 wt % of fibrils treated by protocol 2 were incorporated into a model polydimethylsiloxane network, substantial improvements of the static and dynamic mechanical properties of the composite were noted.
authors.affiliation: Swiss Federal Laboratories for Materials Science and Technology (EMPA), 8600 Dübendorf (Switzerland).
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Swiss Federal Laboratories for Materials Science and Technology (EMPA), 8600 Dübendorf (Switzerland).
authors.forename: Philippe
authors.initials: P
authors.lastname: Tingaut
authors.affiliation: Swiss Federal Laboratories for Materials Science and Technology (EMPA), 8600 Dübendorf (Switzerland).
authors.forename: Daniel
authors.initials: D
authors.lastname: Rentsch
authors.affiliation: Swiss Federal Laboratories for Materials Science and Technology (EMPA), 8600 Dübendorf (Switzerland).
authors.forename: Tanja
authors.initials: T
authors.lastname: Zimmermann
authors.affiliation: Université de Bordeaux, LCPO, UMR 5629, 33600 Pessac (France). gilles.sebe@u-bordeaux.fr, gsebe@enscbp.fr.|CNRS, LCPO, UMR 5629, 33600 Pessac (France). gilles.sebe@u-bordeaux.fr, gsebe@enscbp.fr.
authors.forename: Gilles
authors.initials: G
authors.lastname: Sèbe
mesh_terms: D018554:Avena; D002482:Cellulose / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D012833:Siloxanes / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D012833:Siloxanes; D014867:Water; D002482:Cellulose
keywords: biomass; polymers; renewable resources; silicon; sol-gel processes