APTMS-Modified bacterial cellulose improves paper reinforcement with enhanced interfacial chemistry and durability

Aminosilane functionalization formed stable Si–O–C/Si–O–Si covalent bonds. • Cross-linked siloxane networks enabled uniform reinforcement and aging resistance. • Paper surface property differences caused varied enhancements. • APTMS-BC improved performance across paper surfaces with varying effects. • Reinforced papers showed superior resistance to humid aging and yellowing. Bacterial cellulose (BC) is a promising nanofibrous material for paper conservation, but its inherent hydrophilicity limits interfacial adhesion and durability under humidity. Hence, we employed aminosilane functionalization using 3-aminopropyltrimethoxysilane (APTMS) to construct Si–O–C/Si–O–Si covalent bridges and extend hydrogen-bond networks, thereby reducing surface energy and enhancing the interaction at the BC-fiber interface. Structural analyses (FTIR, XPS) verified successful grafting through new Si–O–C/Si–O–Si signals and an O/C ratio reduction from 0.51 to 0.40, while thermogravimetric analysis revealed higher thermal stability, indicating a denser cross-linked network. The grafting ratio reached a maximum of 12.97% at a BC: APTMS ratio of 1:8, with optimal functionalized conditions identified at 4 h and 45−55°C. Under these conditions, tensile, tear, and folding strength of APTMS-BC reinforced paper (B# newsprint) rose by 68.55%, 128.81%, and 275.94%. Moreover, APTMS-BC significantly improved the mechanical properties and water resistance of paper samples with different interface properties while inducing negligible changes in appearance. During moist heat aging, the strength and yellowing of APTMS-BC reinforced papers demonstrated superior long-term durability. These results establish APTMS-BC as a versatile nanocoating that offers both mechanical reinforcement and environmental protection, providing a promising strategy for sustainable paper conservation. Download: Download high-res image (236KB) Download: Download full-size image