Influence of the addition of microcrystalline cellulose (Mcc) on structural properties of cellulose nanofibrils (NFC) suspensions and films

ABSTRACT Background: In the study of biologically-based materials, nanocelluloses have been showing great prominence and positioned themselves as promising alternatives for the production of different industrialized materials. This polymer has received significant attention recently because it is produced from renewable sources and has unique properties offered by its organic nature and semi-crystalline structure. This work aimed to study the structural properties of suspensions and films by increasing MCC concentration in the form of powder with variations of 5 % (m/m) from 5 % to 30 %. Results: As expected, incorporating MCC increased the Segal index. The morphological analysis showed an increase in the diameters of the structures (NFC / MCC) in the suspensions when the presence of MCC was more significant, and films with cluster formations were observed. The films showed air permeability. Due to the MCC increase, the surface charge had results close to electrostatically stabilized nanosuspensions. An increase in the resistance to thermal degradation of the films was also observed Conclusion: NFC has promising properties for different applications; it provides a film with a stable structure and is resistant to oxygen and tensile stresses. In addition, MCC has excellent potential due to its high crystallinity, structural characteristics, and nature. The increase of the MCC content altered the properties of the suspensions and films produced with NFC, forming a cohesive and resistant film, and influencing the performance of the different properties of the materials evaluated in this study, like air permeability, suspension stability, and thermal resistance.

摘要
背景：在生物基材料研究领域，纳米纤维素（nanocelluloses）始终备受瞩目，已成为各类工业用材料生产中极具潜力的替代原料。该聚合物近期受到广泛关注，因其可从可再生资源中制备，且凭借其有机属性与半结晶结构具备独特性能。本研究旨在探究以粉末形式添加微晶纤维素（MCC）、以5%（m/m）为梯度从5%提升至30%时，悬浮液与薄膜的结构性能。
结果：正如预期，添加MCC可提升赛格尔指数（Segal index）。形貌分析结果显示，当悬浮液中MCC占比更高时，体系内结构（NFC/MCC）的直径增大，且制备得到的薄膜出现团聚结构。该薄膜具备透气性能；随着MCC含量提升，表面电荷检测结果接近静电稳定型纳米悬浮液的水平，同时薄膜的抗热降解性能亦有所提升。
结论：纳米原纤纤维素（NFC）在诸多应用场景中具备优异性能，可制备出结构稳定、耐氧气侵蚀且抗拉伸应力的薄膜。此外，MCC凭借其高结晶度、结构特性与天然属性，展现出极佳的应用潜力。提高MCC含量会改变以NFC为基底制备的悬浮液与薄膜的性能，可形成粘结紧密且兼具力学抗性的薄膜，并对本研究中评估的多项材料性能产生影响，包括透气性能、悬浮液稳定性与抗热降解性能。