In this work, nanocellulose (NC) was prepared by a new route consisting of dissolution of cellulose in phosphoric acid followed by regeneration in water. To facilitate the dissolution, the cellulose was pre-treated with aqueous solution of urea. Although the regenerated cellulose from water had been in nanoscale, its size could be further reduced through ball milling. The composition, structure, and morphology of the materials from different preparation stages were studied by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. NC was then incorporated into the HDPE based wood-plastic composites (WPCs) in a skillful way to guarantee its good dispersion. The influence of addition content of NC on the mechanical and thermal properties of WPCs was investigated comprehensively. WPCs incorporated with NC exhibited an obvious increase in impact strength compared with those without NC. In addition, the Rockwell hardness, Vicat softening temperature and thermal stability of WPCs incorporated with NC were also correspondingly improved. The effect of ball milling on the size of nanocellulose was also investigated. The application results showed that the NC prepared without ball milling was more efficient in enhancing the toughness of WPCs.

在这项工作中，纳米纤维素 (NC) 通过一种新途径制备，该途径包括将纤维素溶解在磷酸中，然后在水中再生。为促进溶解，纤维素用尿素水溶液预处理。虽然从水中再生的纤维素是纳米级的，但通过球磨可以进一步减小其尺寸。分别通过红外光谱（FTIR）、X射线衍射（XRD）和透射电子显微镜（TEM）研究了不同制备阶段材料的组成、结构和形貌。然后以巧妙的方式将 NC 掺入 HDPE 基木塑复合材料 (WPC) 中，以保证其良好的分散性。综合考察了NC添加量对WPCs力学性能和热性能的影响。与未加入 NC 的 WPC 相比，加入 NC 的 WPC 的冲击强度明显增加。此外，加入NC的WPC的洛氏硬度、维卡软化温度和热稳定性也相应提高。还研究了球磨对纳米纤维素尺寸的影响。应用结果表明，未经球磨制备的NC在提高WPCs韧性方面更有效。