title: Investigation into the structural, morphological, mechanical and thermal behaviour of bacterial cellulose after a two-step purification process.
abstract: Bacterial cellulose (BC) is a natural hydrogel, which is produced by Acetobacter xylinum (recently renamed Gluconacetobacter xylinum) in culture and constitutes of a three-dimensional network of ribbon-shaped bundles of cellulose microfibrils. Here, a two-step purification process is presented that significantly improves the structural, mechanical, thermal and morphological behaviour of BC sheet processed from these hydrogels produced in static culture. Alkalisation of BC using a single-step treatment of 2.5 wt.% NaOH solution produced a twofold increase in Young's modulus of processed BC sheet over untreated BC sheet. Further enhancements are achieved after a second treatment with 2.5 wt.% NaOCl (bleaching). These treatments were carefully designed in order to prevent any polymorphic crystal transformation from cellulose I to cellulose II, which can be detrimental for the mechanical properties. Scanning electron microscopy and thermogravimetric analysis reveals that with increasing chemical treatment, morphological and thermal stability of the processed films are also improved.
authors.affiliation: School of Engineering and Material Science and Centre for Materials Research, Queen Mary University of London, London E14NS, UK.
authors.forename: Saharman
authors.initials: S
authors.lastname: Gea
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Reynolds
authors.forename: Nima
authors.initials: N
authors.lastname: Roohpour
authors.forename: Basuki
authors.initials: B
authors.lastname: Wirjosentono
authors.forename: Nattakan
authors.initials: N
authors.lastname: Soykeabkaew
authors.forename: Emiliano
authors.initials: E
authors.lastname: Bilotti
authors.forename: Ton
authors.initials: T
authors.lastname: Peijs
mesh_terms: D002482:Cellulose / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D041822:Gluconacetobacter xylinus / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D020894:Microfibrils / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012972:Sodium Hydroxide; D017550:Spectroscopy, Fourier Transform Infrared; D013718:Tensile Strength; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D020100:Hydrogels; D012972:Sodium Hydroxide; D002482:Cellulose