Fiber and Poglymer Science, University of California , Davis, California 95616, United States.
ACS Appl Mater Interfaces. 2015 Feb 25;7(7):4192-201. doi: 10.1021/am5079489. Epub 2015 Feb 13.
Rice straw holocellulose was TEMPO-oxidized and mechanically defibrillated to produce holocellulose nanofibrils (HCNFs) at 33.7% yield (based on original rice straw mass), 4.6% higher yield than cellulose nanofibril (CNF) generated by the same process from pure rice straw cellulose. HCNFs were similar in lateral dimensions (2.92 nm wide, 1.36 nm thick) as CNF, but longer, less surface oxidized (69 vs 85%), and negatively charged (0.80 vs 1.23 mmol/g). HCNFs also showed higher affinity to hydrophobic surfaces than CNFs while still attracted to hydrophilic surfaces. By omitting hemicellulose/silica dissolution step, the two-step 2:1 toluene/ethanol extraction and acidified NaClO2 (1.4%, pH 3-4, 70 °C, 6 h) delignification process for holocellulose was more streamlined than that of pure cellulose, while the resulting amphiphilic HCNFs were more hydrophobic and self-assembled into much finer nanofibers, presenting unique characteristics for new potential applications.
稻草全纤维素经 TEMPO 氧化和机械纤维化处理，以 33.7%的产率（基于原始稻草质量）生产出全纤维素纳米纤维（HCNF），比相同工艺从纯稻草纤维素中产生的纤维素纳米纤维（CNF）高 4.6%。HCNF 的横向尺寸（2.92nm 宽，1.36nm 厚）与 CNF 相似，但更长，表面氧化程度更低（69%对 85%），带负电荷（0.80mmol/g 对 1.23mmol/g）。HCNF 对疏水面的亲和力也高于 CNF，同时仍对亲水表面有吸引力。通过省略半纤维素/二氧化硅溶解步骤，两步 2:1 甲苯/乙醇提取和酸化 NaClO2（1.4%，pH3-4，70°C，6h）脱木质素过程比纯纤维素更精简，而得到的两亲性 HCNF 更疏水，并自组装成更细的纳米纤维，呈现出独特的特性，具有新的潜在应用。
