This paper takes a comparative approach in characterizing two types of nano-scale cellulosic particles obtained using chemical-free pathways, either by nearcritical water treatment or by high-shear homogenization from the same microcrystalline cellulose (MCC). The nearcritical water treatment efficiently depolymerized cellulose, producing a solid precipitated fraction of low-molecular-weight material containing cellulose II, while homogenization mechanically deconstructed MCC without altering its molecular structure. Both pathways yielded nanocellulose-like materials yet with different morphologies. The mechanically produced, rod-like particles were obtained with high yield. In contrast, the hydrothermal precipitate exhibited more hydrophobic ribbon-like particles that provided a greater level of particle-particle interaction. Both materials successfully acted as stabilizers for oil-in-water Pickering emulsions; however, the hydrothermally-produced material exhibited superior performance, with stable emulsions obtained upon addition of as low as 1.0 wt.% cellulose. These two pathways are highly relevant for altering the structure and properties of MCC and for formulating new, sustainably produced nanocellulose-based materials.

中文翻译：

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从微晶纤维素无化学制备纳米纤维素及其作为Pickering乳化稳定剂的用途

本文采用比较方法来表征使用无化学途径通过近临界水处理或同一微晶纤维素（MCC）的高剪切均质化获得的两种类型的纳米级纤维素颗粒。近临界水处理有效地解聚了纤维素，产生了含有纤维素II的低分子量物质的固体沉淀部分，而均质化则在不改变分子结构的情况下对MCC进行了机械解构。两种途径均产生类似纳米纤维素的材料，但具有不同的形态。机械获得的棒状颗粒以高收率获得。相反，水热沉淀物显示出更多的疏水带状颗粒，其提供了更高水平的颗粒-颗粒相互作用。两种材料均成功地用作水包油Pickering乳液的稳定剂。然而，水热生产的材料表现出优异的性能，通过添加低至1.0重量％的纤维素获得了稳定的乳液。这两个途径与改变MCC的结构和性能以及配制新的，可持续生产的基于纳米纤维素的材料高度相关。