School of Chemistry and Chemical Engineering, South China University of Technology, Wushan Road 381, Guangzhou 510640, PR China.
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Wushan Road 381, Guangzhou 510640, PR China.
Carbohydr Polym. 2022 Nov 15;296:119919. doi: 10.1016/j.carbpol.2022.119919. Epub 2022 Jul 25.
The degree of polymerization (DP) of cellulose plays an essential role in unlocking the superior mechanical potential of wood cellulose nanofibrils (CNFs). However, severe degradation of cellulose chains during the chemical pulping is a big challenge to obtain CNFs with high DP. In this work, we tend to improve the DP of wood CNFs by significantly preserving the native structure of wood fibers in an industrial method. Wood sticks are first pretreated with hydrothermal treatment to partially remove hemicellulose, thus leading to an increased porous structure that facilitates the penetration of cooking liquid and lignin removal during delignification, and dilute-alkali-sulfate pulping is then employed to obtain wood fibers with highest viscosity average DP (DP) of nearly 2400. After that, the as-prepared wood fibers with high DP are separated into CNFs with highest average DP of 1333. Finally, we demonstrate the potential application of wood CNFs with improved DP in the fabrication of strong and tough isotropic films and macrofibers.
纤维素的聚合度（DP）在解锁木材纤维素纳米纤维（CNF）的优异机械潜力方面起着至关重要的作用。然而，在化学制浆过程中纤维素链的严重降解是获得具有高 DP 的 CNF 的一大挑战。在这项工作中，我们倾向于通过在工业方法中显著保留木材纤维的天然结构来提高木材 CNF 的 DP。首先，将木棒进行湿热预处理以部分去除半纤维素，从而形成增加的多孔结构，有利于蒸煮液的渗透和脱木质素过程中木质素的去除，然后采用稀碱-亚硫酸盐法制浆以获得具有最高粘度平均 DP（DP）接近 2400 的木材纤维。之后，将高 DP 的预处理木材纤维分离成具有最高平均 DP 为 1333 的 CNF。最后，我们展示了具有改进 DP 的木材 CNF 在制造强韧各向同性薄膜和宏观纤维方面的潜在应用。
