Surface Treatment of Bacterial Cellulose in Mild, Eco-Friendly Conditions

Abstract

Bacterial cellulose (BC) with increased hydrophobicity is required for several applications including packaging. Surface functionalization of BC may provide good resistance to moisture, increased barrier properties or improved compatibility to polymer matrices. For this purpose, chemical grafting of BC in mild, eco-friendly conditions was carried out using different agents. BC membranes were surface functionalized with vinyl-triethoxy silane (VS) or 3-aminopropyl triethoxysilane (APS), by acylation and acrylation. The efficiency of the surface treatments was highlighted by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, by contact angle measurements and by dynamic mechanical analysis. The morphological investigation by atomic force microscopy and scanning electron microscopy revealed an increased compactness for surface functionalized BC, which correlated well with the different increase of the contact angle. BC treated with APS and VS showed more than a twofold increase in contact angle value. Similarly, the crystallinity degree was reduced to 69.6% and 72.9% after APS and VS treatments as compared with 84.1% for untreated BC, confirming the grafting reaction and the decrease in hydrogen bonding. All the applied treatments delayed the degradation of BC. However, the highest increase in thermal stability was observed for silanes treated membranes. Effective, eco-friendly methods for improving the surface hydrophobicity of bacterial cellulose for food packaging were proposed in this study.

Natural Rubber Latex Foam Reinforced with Micro- and Nanofibrillated Cellulose via Dunlop Method

“…The thermal degradation of NC prepared from BC could be divided into 2 steps. The first step was the main decomposition step, occurring from 200 to 400 °C, where depolymerization, dehydration and decomposition of the cyclic structures were observed [ 6 , 47 ]. The second weight loss of NC from BC corresponded to the pyrolysis of cellulose [ 47 ], which was observed from around 528 °C [ 6 , 47 ].…”

Bacterial Cellulose and Emulsified AESO Biocomposites as an Ecological Alternative to Leather

“…The DSC curve of BC reveals an endothermal degradation peak (T m ) at 362.2 • C, which is attributed to partial pyrolysis with the fragmentation of carbonyl and carboxylic bonds from anhydrous glucose units [67]. BC also shows a narrow weight loss at 351.0 • C (T dmax ), indicating fast degradation, involving dehydration, depolymerization of the main polymer network and the decomposition of glucosyl units followed by the formation of a charred residue [68,69].…”

Nanocellulose Bio-Based Composites for Food Packaging

“…In this latter case, surface functionalisation can be performed to provide antimicrobial and antioxidant properties, to develop sensor systems and to provide sites for specific interaction with different chemical agents. Several approaches as silane grafting, acetylation, alkylation, esterification, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation, carboxymethylation and the use of nanoparticles were used to modify nanocellulose with the abovementioned objectives [ 82 , 83 , 84 , 85 , 86 , 87 , 88 ].…”