Rafi Abdolrahim A, Deiana Luca, Alimohammadzadeh Rana, Engstrand Per, Granfeldt Thomas, Nyström Staffan K, Cordova Armando
FSCN Research Center, Organic Chemistry, Mid Sweden University, Holmgatan 10, 851 70 Sundsvall, Sweden.
FSCN Research Center, High Yield Pulp Technology, Mid Sweden University, Holmgatan 10, 851 70 Sundsvall, Sweden.
ACS Sustain Resour Manag. 2024 Nov 13;1(12):2554-2563. doi: 10.1021/acssusresmgt.4c00266. eCollection 2024 Dec 26.
There is a growing demand for the utilization of sustainable materials, such as cellulose-based alternatives, over fossil-based materials. However, the inherent drawbacks of cellulosic materials, such as extremely low wet strength and resistance to moisture, need significant improvements. Moreover, several of the commercially available wet-strength chemicals and hydrophobic agents for cellulosic material treatment are toxic or fossil-based (e.g., epichlorohydrin and fluorocarbons). Herein, we present an eco-friendly, high-yield, industrially relevant, and scalable method inspired by birch bark for fabricating hydrophobic and strong cellulosic materials. This was accomplished by combining simple surface modification of cellulosic fibers in water using colloidal particles of betulin, an abundant triterpene extracted from birch bark, with sustainable chemical engineering (e.g., lignin modification and hot-pressing). This led to a transformative process that not only altered the morphology of the cellulosic materials into a more dense and compact structure but also made them hydrophobic (contact angles of up to >130°) with the betulin particles undergoing polymorphic transformations from prismatic crystals (betulin III) to orthorhombic whiskers (betulin I). Significant synergistic effects are observed, resulting in a remarkable increase in wet strength (>1400%) of the produced hydrophobic cellulosic materials.
与基于化石的材料相比，对可持续材料（如基于纤维素的替代品）的利用需求日益增长。然而，纤维素材料固有的缺点，如极低的湿强度和防潮性，需要显著改进。此外，几种用于纤维素材料处理的市售湿强化学品和疏水剂是有毒的或基于化石的（如环氧氯丙烷和碳氟化合物）。在此，我们提出了一种受桦树皮启发的环保、高产、与工业相关且可扩展的方法，用于制造疏水且坚固的纤维素材料。这是通过将桦树皮中提取的丰富三萜类化合物桦木醇的胶体颗粒在水中对纤维素纤维进行简单的表面改性与可持续化学工程（如木质素改性和热压）相结合来实现的。这导致了一个变革性的过程，不仅将纤维素材料的形态改变为更致密和紧凑的结构，而且还使其具有疏水性（接触角高达>130°），同时桦木醇颗粒经历了从棱柱晶体（桦木醇III）到正交晶须（桦木醇I）的多晶型转变。观察到显著的协同效应，导致所制备的疏水纤维素材料的湿强度显著提高（>1400%）。
