Evaluation of elasto-plastic properties of bacterial cellulose-hemicellulose composite films

Bacterial cellulose (BC) is a natural biopolymer of β-(1,4)-linked β-D-glucopyranose that forms a homogeneous network of cellulose fibres with high chemical purity and modifiability. Plasticizers of the BC fibre network allow to reduce its brittleness and improve flexibility by reducing the intermolecular forces and increasing the chain mobility, while the opposite effect was observed for the antiplasticizing additives. Therefore, the aim of the current study was to investigate the effect of hemicellulose addition on the elasto-plastic response of BC-hemicellulose composite films depending on the specific type of hemicellulose and its concentration. BC-hemicellulose composite films were produced by K.xylinum bacteria strain in the hemicellulose-modified medium. The presence of xylan and arabinoxylan in the culturing medium resulted in an increase in the plastic deformation of the composite films, its maximum stress and maximum strain, which was opposite to the effects of glucomannan and xyloglucan. Spectral studies revealed that the deformation of the hemicellulose polysaccharides played a minor role in opposing of applied loads. The contribution of the hydrogen bond network in opposing of applied loads was comparable to that of the glycosidic bonds. Stretching vibrations of the structural bonds of BC-hemicellulose composite films determined elastic deformation most, compared to other bonds.