Mechanical and structural properties of environmental green composites based on functionalized bacterial cellulose

In this work TiO2 and highly inorganic ceramic clay were successfully immobilized into Bacterial Cellulose (BC), produced by Komagataeibacter xylinus K2G30 (UMCC 2756) strain, in different proportions. The morphology, structure, and mechanical properties of the composites, fabricated by wet mechanical mixing, were investigated through a multi-technique approach: density measurement, optical and electronic microscopy, FTIR spectroscopy, contact angle measurement and mechanical tensile testing, before and after aging, under UV light exposure. Results suggest completely different behavior by using TiO2 or Clay. In fact, porous fragile structures were obtained by employing Clay, whereas more compact and plastic-like specimen by using TiO2, due to different chemical bonding developed through H-bonding, as confirmed by FTIR. Enhanced tensile resistance at break was found for a content of TiO2 equal to 20 wt% and this result was not affected by aging, under UV light exposure. This study demonstrates how ceramic inorganic fillers for BC are able to act in completely different way, becoming of interests in different fields such as hydrophilic porous membranes for Clay and compact plastic-like film for textile industry with TiO2 addition.