Naturally synthesised polymers cellulose

Films are continuous, thin, clear, coloured or opaque materials derived from organic polymers. Most polymers are synthesised whereas the cellulose -based films mentioned previously are mainly of natural origin. 

Polymers are large molecules composed of two to several thousand simple molecules as repeating units, called monomers. Monomers are converted into the polymer through special reactions known as polymerisation. Hence the polymer is the pure material. Almost all synthetic polymers are synthesised from petroleum, although there are natural polymers as well, for example, cellulose, wool and so on. 

In addition to plant-derived cellulose, cellulose can also be synthesised by bacteria such as from the Acetobacter species. By culturing cellulose-producing bacteria in the presence of natural fibres in an appropriate culture medium, bacterial cellulose is preferentially deposited in situ onto the surface of natural fibres. The introduction of bacterial cellulose onto natural fibres provides new means of controlling the interaction between natural fibres and polymer matrices. Coating of natural fibres with bacterial cellulose not only facilitates good distribution of bacterial cellulose within the matrix, but also results in an improved interfacial adhesion between the fibres and the matrix. This enhances the interaction between the natural fibres and the polymer matrix through mechanical interlocking. 

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