Freeze-dried bacterial cellulose

Figure 1. SEM Micrographs of Freeze Dried Bacterial Cellulose (A transverse section, B top view)...

Fig. 2.1 SEM micrograph of a freeze dried bacterial cellulose showing the coherent nanofiber network synthesized by the Gluconacetobacter bacteria [13]...

While many researchers use bacterial cellulose in its native form to create polymers, and some treat the bacterial cellulose by homogenization or hydrolyzation prior to casting, there is very little in the literature about the dissolution of bacterial cellulose as part of a method to create composites. One method that has used the dissolution of bacterial cellulose is electrospinning. Chen et al. [148] used the ionic liquid 1-allyl-3-methylimidazolium chloride to dissolve freeze-dried bacterial cellulose pieces at 70°C while stirring. DMSO was added to the solution to adjust the viscosity at room... 

Kim SS, Jeon JH, Kee CD et al (2013) Electro-active hybrid actuators based on freeze-dried bacterial cellulose and PEDOT PSS. Smart Mater Stmct 22(8) 085026 Kim FD, Randriamahazaka H, Oh IK (2014a) Highly conductive, capacitive, flexible and soft electrodes based on 3D graphene-nanotube-palladium hybrid and conducting polymer. Small... 

The pyrolysis of CellNFs is expected to result in the formation of CNFs. Due to their small diameter, cellulose-based CNFs may require lower temperature for graphitization [72]. However, little research has been reported on the production of nanoscale CFs by pyrolysis of CellNFs. It is expected that the molecular and morphological properties of precursors strongly affect those of the pyrolyzed carbon material. Ishida et al. investigated the carbonization of freeze-dried bacterial and tunicate CellNFs and found that the carbon residue retained its fibrous morphology by using HCl as... 

Tobacco primary cell wall and normal bacterial Acetobacter xylinum cellulose formation produced a 36.8 3A triple-stranded left-hand helical microfibril in freeze-dried Pt-C replicas and in negatively stained preparations for transmission electron microscopy (TEM). A. xylinum growth in the presence of 0.25 mM Tinopal disrupted cellulose microfibril formation and produced a... 

Fig. 2 Shape and structure of BC. a molecular cellulose chain, b scanning electron microscopy (SEM) of freeze-dried nanofiber network (magnification 10000), c pellicle of bacterial nanocellulose from common static culture...

BC is pure cellulose made by bacterial fabrication via biochemical steps and self-assembling of the secreted cellulose fibrils in the medium. Shaping of BC materials in the culture medium can be controlled by the type of cultivation and kind of bioreactor and then it obtained BC hydrogel or BC in dry state by methods like freeze-drying [1]. 

Cai et al. [203] prepared a porous scaffold using bacterial cellulose and poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P(3HB-co-4HB)) with a trifluoroacetic acid as a co-solvent, and by freeze-drying the solution to remove the co-solvent. They determined that the scaffold presented a three-dimensional network with improved mechanical properties over P (3HB-co-4HB) alone. 

A method developed from temperature induced phase separation was completed to obtain PLA/bacterial cellulose composites [174]. In this work, bacterial cellulose was added to 1,4-dioxane and homogenized before PLA was added and dissolved before the mixture was added dropwise into a liquid nitrogen bath. The precipitate was collected and freeze-dried to produce composite microspheres, which were then fed into a twin-screw extruder and were mixed at 180°C, extruded, pelletized and hot press compression moulded into films. PLA films containing bacterial cellulose showed an increase in tensile modulus, with composites containing bacterial cellulose, and chemically modified bacterial cellulose shown to have improvements over PLA alone [174]. 

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