title: Nanostructured membranes based on native chitin nanofibers prepared by mild process.
abstract: Procedures for chitin nanofiber or nanocrystal extraction from Crustaceans modify the chitin structure significantly, through surface deacetylation, surface oxidation and/or molar mass degradation. Here, very mild conditions were used to disintegrate chitin fibril bundles and isolate low protein content individualized chitin nanofibers, and prepare nanostructured high-strength chitin membranes. Most of the strongly 'bound' protein was removed. The degree of acetylation, crystal structure as well as length and width of the native chitin microfibrils in the organism were successfully preserved. Atomic force microscopy and scanning transmission electron microscopy, showed chitin nanofibers with width between 3 and 4 nm. Chitin membranes were prepared by filtration of hydrocolloidal nanofiber suspensions. Mechanical and optical properties were measured. The highest data so far reported for nanostructured chitin membranes was obtained for ultimate tensile strength, strain to failure and work to fracture. Strong correlation was observed between low residual protein content and high tensile properties and the reasons for this are discussed.
authors.affiliation: Department of Fiber and Polymer Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Ngesa Ezekiel
authors.initials: NE
authors.lastname: Mushi
authors.affiliation: Department of Fiber and Polymer Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Nuria
authors.initials: N
authors.lastname: Butchosa
authors.affiliation: Department of Fiber and Polymer Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Michaela
authors.initials: M
authors.lastname: Salajkova
authors.affiliation: Department of Fiber and Polymer Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden; School of Biotechnology, Royal Institute of Technology, AlbaNova University Centre, SE-106 91 Stockholm, Sweden.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Fiber and Polymer Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden; Wallenberg Wood Science Center, Royal Institute of Technology, SE-100 44 Stockholm, Sweden. Electronic address: blund@kth.se.
authors.forename: Lars A
authors.initials: LA
authors.lastname: Berglund
mesh_terms: D000107:Acetylation; D000818:Animals; D002686:Chitin / Q000737:chemistry* / Q000302:isolation & purification; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning / Q000379:methods; D057139:Nanofibers / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D008121:Nephropidae / Q000737:chemistry; D055620:Optical Phenomena; D013718:Tensile Strength
chemical_list: D008567:Membranes, Artificial; D002686:Chitin
keywords: Bound protein; Chitin nanofiber; Mechanical properties; Nanopaper membranes; Preparation; Structure