高频超声法纳米纤丝化纤维素的制备与表征

 为制备均一直径和高长径比的纳米纤丝化α-纤维素(NFC),采用化学预处理和高频超声相结合的方法对落叶松木材进行脱除半纤维素、木质素以及纤丝化处理。采用扫描电子显微镜(SEM)、傅里叶变换红外吸收光谱(FTIR)和X-射线衍射仪(XRD)对制备的NFC的形态特征、化学结构、晶型结构及结晶度进行表征。结果表明,制备的NFC具有均一直径(约35nm)和高长径比(>280);NFC的晶型结构为纤维素Ⅰ型,结晶度为62.8%,比原料提高了14.2%;并利用NFC水分散液经冷冻干燥制备成了超透明的NFC薄膜和柔性的超轻泡沫材料。文中提供了一种新的制备纳米纤化天然生物质纤维素的有效方法,且具有高结晶度、高长径比和纳米尺寸的NFC是一种具有较大应用潜力的新型纳米材料。

Preparation and Characterization of Nanofiber Films and Foams Based on Ultrasonic Nanofibrillated Cellulose from Wood

To obtain the nanofibriled-cellulose(NFC) with uniform diameter and high aspect ratio, a chemical pretreatment is employed to remove the hemicellulose and the lignin of Larix gmelini with a subsequent ultrasonic treatment. The chemical characteristics, the crystalline type, the crystallinity and the morphological features of the as-prepared NFC are analyzed by the Fourier Transform Infrared Spectroscopy (FTIR), the X-Ray Diffraction (XRD) and the Scanning Electron Microscopy(SEM). It is shown that the obtained NFC has a uniform diameter of about 35nm and a high aspect ratio(>280). The crystalline type of the NFC is the cellulose I type, and the crystallinity reaches 62.8%, increased by 14.2% as compared with the raw material wood. Simultaneously, the high transparent NFC film and the ultralight flexible NFC foam are also fabricated by using the freeze drying technique.