Bacterial cellulose composites

Bacterial cellulose has been used as a material in combination with many others to develop composites. It has been used with materials such as xmsaturated polyester [185], the conducting polymer polyaniline [158-162, 186], as well as various acrylic and phenolic resins [178, 187-189]. It has also been used with several biodegradable materials such as cellulose acetate butyrate (CAB) [146,190], PLA [167,174,191,192], PHB [193-195], PVA [196,197], and thermoplastic starch [198,199], to produce completely biodegradable composites. Though renewable and biodegradable composites are the focus of this review, techniques and resulting composites from non-renewable sources are also mentioned. 

Several researchers have used an impregnation method to develop composites with bacterial cellulose, similar to the modification method described previously, except that the material used forms a sheet rather than individual particles upon drying. The soaking of the cellulose may occur from dry, or never-dried films, or films that have 

Solution blending is a method of combining materials with ease, however it is not a method often used for composites involving bacterial cellulose, as bacterial cellulose is difficult to disperse or dissolve. Despite this, there have recently been an increasing number of reports that are using dispersed bacterial cellulose in solution with dissolved host polymers. Such reports are listed below. 

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. 

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 

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Shah, N., Ul-Islam, M., Khattak, W. A., and Park, J. R (2013). Overview of bacterial cellulose composites A multipurpose advanced material,... 

Saibuatong, O., and Phisalaphong, M. (2010). Novo aloe vera-bacterial cellulose composite film from biosynthesis, Carhohvd. Polvm.. 79, 455-460. 

Jung, R., Jin, H.-J. Preparations of silk fibroin/bacterial cellulose composite films and their mechanical properties. Key Eng. Mater. 342-343, 741-744 (2007)... 

Shah N, Ul-Islam M, Khattak WA, Park JK (2013) Overview of bacterial cellulose composites a multipurpose advanced material. Carbohydr Polym 98 1585-1598... 

PVA-BC Poly(vinyl alcohol) bacterial cellulose composite... 

Basnet , P., Knowles, J.C., Pishbin, F., Smith, C., Keshavarz, T., Boccaccini, A.R., Roy, I., 2012. Novel poly(3-hydroxyoctanoate)/bacterial cellulose composites as potential materials for biodegradable stent. Advanced Biomaterials 14 (6), 330—343. 

Astley, M., Chanliaud, E., Donald, A., Gidley, M.J., 2003. Tensile deformation of bacterial cellulose composites. International Journal of Biological Macromolecules 32, 28—35. 

Impregnation can be used as a method of directly modifying the surface of the bacterial cellulose, but can also be used as a method of producing bacterial cellulose composites with other materials. 

These recent reports demonstrate that it may be possible to adapt a more traditional method, such as melt compounding, to disperse bacterial cellulose and use this material as a reinforcing phase in composites. This type of technique can be easily upscaled and may be adapted provide a method to produce bacterial cellulose composites for commercial applications. 

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]. 

Keywords Bacterial cellulose, composite, magnetic materials, catalyst, fuel cell, optical device, electrically conducting material... 

The first exploratory investigation on the use of bacterial cellulose as a liquid-loaded pad for wound care was performed by Johnson and Johnson in the early 1980s. Bacterial cellulose composites blended with chitosan, polyethylene glycol (PEG), and gelatin were tested for potential biomedical applications, and the products look like a foam in structure. Cell adhesion studies showed that these composite products have a greater biocompatibility than pure bacterial cellulose. 

Kim, J., Cai, Z., Chen, Y., 2010. Biocompatible bacterial cellulose composites for biomedical application. Journal of Nanotechnology in Engineering and Medicine 1 (1) 011006. 

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