One-Sided Surface Modification of Bacterial Cellulose Sheet as 2,3-Dialdehyde

A unique property of bacterial cellulose (BC) produced by Gluconacetobacter xylinus is its highly swollen gel sheet-shaped form. This property prompted us to modify its surface to make a functional cellulose sheet. In this study, we attempted one-sided surface modification of BC by the introduction of reactive 2,3-dialdehyde derivatives (DABC) preferentially with limited periodate oxidation. The results indicate that the best reaction condition for one-sided modification was 3 h at 50°C with a periodate solution (cellulose/sodium periodate near 1.21, w/w) in the dark. Semi-dried BC sheets (thickness 20 µm, moisture content 96.7%) have high reactivity for the modification. Selectivity of the reaction was determined by attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy. The products were further characterized by scanning electron microscopy (SEM), wide-angle X-ray diffractometry (WAXD), thermogravimetric analysis (TGA) and tensile testing (TT). The results from SEM indicate that the cellulose microfibrils maintained their original diameter, and those from WAXD show that the crystalline allomorph Iα is retained after the reaction. Progression of the reaction was monitored by TGA and TT analyses.