Wallenberg Wood Science Center, KTH Royal Institute of Technology, Stockholm, Sweden.
Carbohydr Polym. 2013 Jan 30;92(1):775-83. doi: 10.1016/j.carbpol.2012.09.090. Epub 2012 Oct 8.
Dry ultra-porous cellulose fibres were obtained using a liquid exchange procedure in which water was replaced in the following order: water, methanol, acetone, and finally pentane; thereafter, the fibres were dried with Ar(g). The dry samples (of TEMPO-oxidized dissolving pulp) had a specific surface area of 130 m(2)g(-1) as measured using BET nitrogen gas adsorption. The open structure in the dry state was also revealed using field emission scanning electron microscopy. This dry open structure was used as a scaffold for in situ polymerization. Both poly(methyl methacrylate) and poly(butylacrylate) were successfully used as matrix polymers for the composite material (fibre/polymer), comprising approximately 20 wt% fibres. Atomic force microscopy phase imaging indicated a nanoscale mixing of the matrix polymer and the cellulose fibril aggregates and this was also supported by mechanical testing of the prepared composite where the open fibre structure produced superior composites. The fibre/polymer composite had a significantly reduced water absorption capacity also indicating an efficient filling of the fibre structure with the matrix polymer.
采用液-液置换的方法制备了干燥的超高多孔纤维素纤维，置换过程中，纤维素纤维中的水首先被甲醇置换，然后被丙酮置换，最后被戊烷置换；随后，氩气氛围下对纤维进行干燥处理。采用 BET 氮气吸附法对干燥后的（TEMPO 氧化溶解浆）样品进行比表面积测试，结果表明样品的比表面积为 130 m(2)g(-1)。采用场发射扫描电子显微镜揭示了干燥状态下的开放结构。这种干燥的开放结构被用作原位聚合的支架。成功地将聚（甲基丙烯酸甲酯）和聚（丙烯酸丁酯）用作复合材料（纤维/聚合物）的基体聚合物，其中纤维的含量约为 20wt%。原子力显微镜相成像表明，基体聚合物与纤维素原纤聚集体之间存在纳米级混合，这也得到了复合材料力学性能测试的支持，其中开放纤维结构制备的复合材料具有更优异的性能。此外，纤维/聚合物复合材料的吸水率显著降低，这也表明纤维结构被基体聚合物有效填充。
