Surface Modifications of Biofibers Using Bacterial Cellulose

The hydrophilic nature of cellulose fibers often results in poor compatibiHty with hydrophobic polymer matrices. Therefore, it becomes necessary to modify the surface of natural fiber for better binding between fiber and matrix. Chemicals are commonly used for the modification of cellulosic materials but large amount of solvents are also usually involved. Surface modification of biofibers using bacterial cellulose (BC) is one of the best methods for greener surface treatment of biofibers. 

BC has gained attention in the research area for the encouraging properties it possesses, such as significant mechanical properties in both dry and wet states, porosity, water absorbency, moldability, biodegradabiUty, and excellent biological affinity [96]. Because of these properties, BC has a wide range of potential apphcations. 

The introduction of BC onto biofibers provides new means of controlling the interaction between natural fibers and polymer matrices. Coating of biofibers with BC does not only fadHtate good distribution of BC within the matrix but also results in an improved interfadal adhesion between the fibers and the matrix. This enhances the interaction between the biofibers and the polymer matrix through mechanical interlocking. BC-coated natural fibers introduced nanocellulose at the interface between the fibers and the matrix, leading to increased stiffness of the matrix around the natural fibers [97, 98). 

Acetohacter xylinum (or Glucomcetobacter xylinus) is the most effident producer of BC. BC is secreted as a ribbon-shaped fibril, less than 100 nm wide, which is composed of much finer 2-4 nm nanofibrils [99, lOOj. In comparison to the methods for obtaining nanocellulose through mechanical or chemo-mechanical processes, BC is produced by bacteria through cellulose biosynthesis and the building up of bundles of microfibrils [lOlj. 

In most of the applications, general plants or vegetable fibers (biofibers) are used for the preparation of reinforced plastic materials. The commonly used biofibers 

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