Bio-based materials have garnered significant attention as packaging materials for food preservation and food security around the worlds due to their green, renewable and sustainable properties. Therefore, cellulose nanofibrils (CNF) has become a key bio-economic priority due to its abundance, high surface area, excellent mechanical properties and most importantly presence of abundance of hydroxyl group in the structure that can be chemically modified. However, their high hydrophilicity and gel-like behavior, limits their use in some applications. Thus, to overcome this limitation, the available hydroxyl groups can be chemically modified to increase their compatibility and to impart desirable novel properties. Thus, CNF samples with different levels of fibrillation and fines were produced by controlling mechanical energy and a mild acetylation reaction was carried out to chemically modify CNF while preserving the integrity of the original morphology and native crystalline structure. Degree of substitution (DS) was measured to quantify surface modification of NFC, which increased with mechanical energy to reach a maximum value and dropped after continuing to increase the energy levels despite reaching the highest level of fibrillation and fines content. The CNF samples showing highest reactivity was used for barrier properties evaluation. The oxygen permeability of CNF films was studied at different relative humidity (RH). The effect of moisture on the barrier and mechanical properties of the films was further studied using water vapor sorption isotherms and by humidity scans in dynamic mechanical analysis. Air and oil resistance increased with the increase in degree of fibrillation of CNF. The influences of the degree of fibrillation on the microstructure and optical properties of the films were evaluated by scanning electron microscopy (SEM) and light transmittance measurements, respectively. This study provides a promising ecofriendly strategy to use modified CNF for optimized performance in barrier properties applications.<br/>

Elucidation of chemical reactivity of cellulose nanofibrils with varying degree of fibrillation for barrier properties application

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.