液氮冷冻干燥法制备纳米纤维素气凝胶

发布时间：2018-02-06 04:50

本文关键词： 气凝胶叔丁醇液氮冷冻干燥纳米纤维素　出处：《林业工程学报》2017年04期 　论文类型：期刊论文

【摘要】：纤维素气凝胶被誉为继有机气凝胶和无机气凝胶之后的新一代气凝胶,是新生的第三代材料,在吸附材料等领域具有广阔的应用前景。笔者先以微晶纤维素(MCC)为原料经硫酸水解法制得纳米纤维素(NCC),再通过无机盐溶液物理凝胶成型法、叔丁醇置换和液氮冷冻干燥制备球形纤维素气凝胶。利用场发射扫描电子显微镜(SEM)、万能力学试验机、热重分析仪、全自动比表面积及孔隙分析仪对所制备的纳米纤维素气凝胶的力学性能、微观形貌、比表面积、孔径分布及热稳定性进行表征分析。结果表明,液氮冷冻干燥法制备的球形纳米纤维素气凝胶主要为疏松多孔的三维层状结构同时存在少量三维网络结构,其比表面积在104.07~164.97 cm~2/g之间,孔径主要分布在10~25 nm内;纳米纤维素气凝胶的力学性能、压缩强度、密度随着纳米纤维素质量分数的增加而变大;纳米纤维素气凝胶的热稳定性与微晶纤维素和纳米纤维素相似。
[Abstract]:Cellulose aerogels are regarded as the new generation aerogels after organic aerogels and inorganic aerogels. The nanocellulose was prepared by sulfuric acid hydrolysis from microcrystalline cellulose MCCs and then formed by physical gel method of inorganic salt solution. Spherical cellulose aerogels were prepared by replacement of tert-butanol and freeze-drying of liquid nitrogen. Field emission scanning electron microscopy (SEM), universal mechanical testing machine and thermogravimetric analyzer (TGA) were used to prepare spherical cellulose aerogels. The mechanical properties, micromorphology, specific surface area, pore size distribution and thermal stability of the prepared nano-cellulose aerogels were characterized by automatic specific surface area and pore size analyzer. The spherical nano-cellulose aerogels prepared by freeze-drying of liquid nitrogen mainly consist of porous three-dimensional layered structure and a small amount of three-dimensional network structure. The specific surface area is between 104.07 and 164.97 cm~2/g, and the pore size is mainly within 1025 nm. The mechanical properties, compressive strength and density of nano-cellulose aerogels increase with the increase of the mass fraction of nano-cellulose. The thermal stability of nano-cellulose aerogels is similar to that of microcrystalline cellulose and nano-cellulose.
【作者单位】：南京林业大学材料科学与工程学院;
【基金】：国家林业公益性行业科研专项(201504603)
【分类号】：O636.11;O648.17

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