纳米纤维素碱法制备及光谱性质

在纳米尺寸范围操控纤维素分子,由此创制出具有优异功能的新纳米材料是纤维素科学的前沿领域。纳米纤维素作为一种可再生生物材料已成为国内外研究热点,研究开发新型的简单、绿色、低能耗、快速、高效的纳米纤维素制备方法显得尤为重要。该研究采用简易可行的碱性水解法制备得到粒径较小且分散性较好的纳米纤维素。同时采用了电子显微镜、X射线粉末衍射仪和傅里叶红外光谱仪对所制备纳米纤维素进行了表征,研究了其结构与谱学性质。所制备样品为准球形纳米纤维素,颗粒尺寸约为20～40 nm,样品仍属于纤维素Ⅰ型,结晶度为79.71%,晶粒平均尺寸为3～6 nm。结果表明,碱水解法制备纳米纤维素方法具有简易可行、得率高的优点,研究可为纳米纤维素的高效制备提供一条新途径。

Preparation and Spectrum Properties of Cellulose Nanoparticles

Manipulating cellulose molecules in nanosize range to create excellent nano materials is the frontier of cellulose science. Cellulose nanoparticles, a kind of renewable biomaterial, have become the research focus home and aboard. It is of great importance to develop a simple, green, low energy-consuming, rapid and efficient method to prepare cellulose nanoparticles. In the present paper, cellulose nanoparticles (CNP) which enjoy good dispersity and nanosize were prepared by alkaline hydrolysis in a simple and feasible way, with microcrystalline cellulose (MCC) as the raw material. Moreover, the size and morphology, crystal structure and spectrum properties of the cellulose nanoparticles were analyzed by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR). TEM images demonstrate that the prepared samples are in quasi-sphere shapes with good dispersity and with size about 20-40 nm. The SEM images of the samples show that the purified cellulose nanoparticles can be obtained after dialysis treatment to remove salt particles. The XRD results show that the microcrystalline cellulose and cellulose nanoparticles almost have the same diffraction peaks in cellulose I crystal form. Because of the damage of amorphous region of MCC by alkaline hydrolysis, the crystallinity of produced samples increases by up to 79.71%. The grain size was calculated with Scherrer’s formula, and the average size is about 3-6 nm. Furthermore, the FTIR spectra suggest that the characteristic peaks on the graphs of cellulose nanoparticles have no significant change compared to natural cellulose, which indicates that the sample remains as the basic chemical groups of cellulose. The results show that preparing cellulose nanoparticles (CNP) by alkaline hydrolysis enjoys the ease to operate and can produce high yield, and therefore the study offers a new approach to obtaining cellulose nanoparticles with nanosize and good dispersion.