The effect of polyethylene glycol-citric acid (PEG-Ca) addition on mechanical properties of dry bacterial cellulose film

Bacterial cellulose (BC) is natural and can be a source of nonwoven materials for biomedical applications. The mechanical properties of the film are arguably related to the strength of the hydrogen bonds of each glucose subunit in the BC. However, in a dry state, the film loses the properties, thereby making it more brittle. In this work, polyethylene glycol with a molecular weight of 600 g/mol (PEG-600) and citric acid (CA) was selected as a plasticizer and a crosslinker, respectively. Various concentrations of aqueous PEG and CA mixtures with different molar ratios were applied into the BC film by immersion. Other factors, such as the drying process of the wet BC gel and its thickness, were also considered. The mechanical properties of an as-obtained dried film were characterized further.