超临界预处理-球磨法制备纤维素纳米纤丝及其表征

Preparation and Characterization of Cellulose Nanofibers by Supercritical Pretreatment-Ball Milling

中文关键词:  纤维素纳米纤丝（CNF）  微纤维化纤维素（MFC）  超临界CO₂/乙醇  球磨法

Key Words:cellulose nanofiber （CNF）  micro-fibrotic cellulose （MFC）  supercritical CO₂/ethanol  ball milling

中文摘要:

      以微纤维化纤维素（MFC）为原料，通过超临界CO₂/乙醇预处理结合球磨法制备纤维素纳米纤丝（SCB-CNF），探讨了超临界CO₂/乙醇预处理条件对MFC的影响，并与2，2，6，6-四甲基哌啶-1-氧自由基（TEMPO）预处理结合微流体均质法（TMH）制备的纤维素纳米纤丝（TMH-CNF）进行对比研究，采用扫描电子显微镜（SEM）、场发射扫描电子显微镜（FE-SEM）、X射线衍射仪（XRD）和热重分析仪（TG）对样品进行表征。结果表明，超临界CO₂/乙醇预处理可将束状MFC分解为单根纤维，使MFC的长度和直径明显减小；超临界CO₂/乙醇预处理后的纤维素（P-MFC）的结晶度随预处理时间和温度的变化呈先升高后降低的趋势；SCB-CNF的热稳定性和结晶度均高于TMH-CNF，且形态呈针束状，长度远小于TMH-CNF，更易分散，在复合材料和生物医药（药物输送）等领域具有潜在的应用价值。

Abstract:

      Cellulose nanofiber （SCB-CNF） was prepared from micro-fibrotic cellulose （MFC） by supercritical CO₂/ethanol pretreatment combined with ball milling. The effects of supercritical CO₂/ethanol pretreatment conditions on MFC were explored and SCB-CNF was further compared with cellulose nanofiber （TMH-CNF） prepared by 2，2，6，6-tetramethylpiperidine-1-oxygen radical （TEMPO） pretreatment combined with microfluidics homogenization （TMH）. The as-prepared CNFs were characterized by scanning electron microscopy （SEM）， field emission scanning electron microscopy （FE-SEM）， X-ray diffractometer （XRD）， and thermogravimetric （TG） analysis. The results showed that the MFC bundle was decomposed into single fiber by supercritical CO₂/ethanol pretreatment， and the length and diameter of which were significantly reduced. The crystallinity of cellulose （P-MFC） pretreated by supercritical CO₂/ethanol increased firstly and then decreased along with the variation in pretreatment time and temperature. Compared with TMH-CNF， the needle-like SCB-CNF is of higher thermal stability and crystallinity， shorter length， and is easier to be dispersed， exhibiting potential application value in composite materials， biomedicine （drug delivery）， and other fields.