Bacterial Cellulose and Its Polymeric Nanocomposites - The Nanoscience and Technology of Renewable Biomaterials - page 244

5 m

µ

Bacterial Cellulose Bacterial Cellulose

5 µ m

BC/Glucuronoxylan Composite BC/Glucuronoxylan Composite

Figure 9.12 Micrographs of bacterial cellulose and bacterial cellulose/Glucoronoxylan
nanocomposites. (Reprinted from Polymer, 46, Dammstrom, S.; Salmen, L.; Gaten-
holm, P., The effect of moisture on the dynamical mechanical properties of bacterial
cellulose/glucuronoxylannanocomposites,10364-10371,Copyright(2005),withpermission
fromElsevier.)

the cellulose chain and therefore the production of copolymers fibers rather than BC
nanocomposites (33, 35, 37), other studies have shown that true nanocomposites can be
formed by immersing a purified BC pellicle in a chitosan solution followed by solvent
casting (34, 36). The resulting nanocomposites were considered ideal for wound dress-
ing applications (34). The potential of BC/chitosan nanocomposite as membranes has
also been demonstrated (36). Upon impregnation of BC with chitosan, the porous struc-
ture of the BC was masked as chitosan filled the pores of the BC fleece (36). Besides
chitosan lowered the mechanical properties of the membrane from a tensile strength of
74 MPa to 54 MPa while elongation at break increased from 6.8% to 7.4%. No clear
chemical bonding between cellulose and chitosan moieties was detected by FTIR. How-
ever, pervorative experiments demonstrated that the nanocomposite had good potential
to separate ethanol/water azeotrope (36).
Proteins, including gelatin and silk proteins, have also been used in combination with
bacterial cellulose to develop high mechanical strength double network hydrogels or
dry nanocomposites (38-40). While bacterial cellulose in the wet state has high tensile
properties, its compressive properties are mediocre limiting its utilization in various