The Mechanical Strength and Morphology of Bacterial Cellulose Films: The Effect of NaOH Concentration

Bacterial cellulose (BC) is a natural material with attractive physical properties produced by Acetobacter xylinum. Commonly, BC is subjected to a chemical treatment prior to use. Therefore, this study aimed to investigate the effect of chemical treatment using alkali (NaOH) with the various concentrations on the mechanical strength of the resulting BC films. The research method included BC film production using a pineapple peel extract as the main culture material. The resultant BC film was treated with NaOH solution with concentrations of 0%, 1%, 5%, and 10% and then dried in the oven. The mechanical strength of each sample was evaluated by a tensile test, and the film morphology was observed by scanning electron microscopy (SEM). The results showed that the tensile strength of the BC film before the treatment was 208 MPa and decreased to 165 MPa after the treatment with the highest concentration of NaOH because some BC component was dissolved in NaOH solution causing bulk fractured layers. The NaOH concentrations of 1%, 5%, and 10% resulted in the strains of BC films by 2.96%, 3.64%, and 3.00%, respectively. The chemical treatment of NaOH caused BC films to swell and damage to the network and layers in BC film.