生物质纳米材料的结构和物理性能

摘要：细菌纤维素作为一种新型生物质纳米材料在气凝胶领域具有很大的前景。本毕业设计以细菌纤维素为原料常压干燥制备气凝胶，并为了降低常压干燥过程中孔隙的收缩与坍塌，对湿凝胶进行N-β-氨乙基-γ-氨丙基聚二甲基硅氧烷（MA）疏水化处理。分别通过润湿角检测仪、场发射扫描电镜（FESEM）以及氮气吸脱附实验对制备的细菌纤维素气凝胶样品的疏水性、微观形貌，以及孔隙结构进行测试与表征。润湿角检测结果表明，MA修饰的气凝胶的疏水性与处理时间有关，在处理时间从0增加到7min时，样品的水接触角从14.50°增加到33.50°；处理时间增加到20min时，水接触角超过90°达到90.50°；处理时间28min时疏水性达到最大（静态水接触角最大）。FESEM结果表明，MA修饰16min的气凝胶孔结构相对较好的保留了下来，孔径在纳米级；氮气吸脱附实验表明：经MA修饰的样品其等温线线型属于第IV类等温线，BJH孔径分布为介孔多位于孔宽3.88nm和2.5nm附近，BET比表面积为3.870397m2/g，孔径分布范围为0.7nm到226.5nm。

这些实验结果表明，采用MA修饰纤维素湿膜可以有效地减小在其常压干燥过程中其孔隙的坍塌。

关键词生物质材料、细菌纤维素、气凝胶、MA、常压干燥、氮气吸脱附

Title The Structure and Physical Properties of Biomass Nano Materials

Abstract ：As one kind of new biomass nano materials, bacterial cellulose (BC) has a great potential application in aerogel. My dissertation chose BC as one raw material of aerogel prepared by ambient drying. In order to reduce the pore shrinkage and collapse in the drying process, we treat cellulose by hydrophobic treatment of trimethylchlorosilane (MA). The properties of BCA have been characterized and analyzed by means of FESEM, detection of wet angle and nitrogen adsorption- desorption techniques. According to the detection result of wet angel, when the handling time of MA increases from 0 to 7 min, the wet angel increases from 14.5°to 33.5°, and the wet angel increases over 90°while the handling time comes to 20 min. The hydrophobicity reaches the maximum at 28 min (water static contact angle reaches the maximum). The result of FESEM shows that the aerogel dealt with MA for 16min reserves the nanoscale pore structure. The nitrogen adsorption- desorption techniques shows that the isothermal line type of the sample dealt with MA belongs to the fourth type isotherm, and the BJH pore size distribution is mesoporous at the pore size of 3.88 nm and 2.5 nm. Also, it has a bet surface area of 3.870397 m2/g, and the pore size arrange from 0.7 nm to 226.5 nm. In brief, wet BCA film dealt with MA can decrease the shrinkage of holes during ambient drying effectively.

Keywords biomass material, bacterial cellulose, aerogel，MA，ambient drying， nitrogen adsorption-desorption

1引言.1

1.1纤维素1

1.1.1纤维素的化学结构2

1.1.2纤维素的聚集态结构.2

1.1.3纳米纤维素.4

1.1.4纤维素纳米纤维.5

1.1.5纤维素纳米晶.5

1.1.6细菌纤维素.6

1.1.7纳米纤维素的制备.8

1.2甲壳素.9

1.2.1甲壳素的结构和性质9

1.2.2纳米甲壳素9

1.2.3甲壳素的制备10

1.3发展和展望11

2.细菌纤维素气凝胶的制备13

2.1实验材料.13

2.2细菌纤维素气凝胶的制备.14

2.3表征.14

3.实验数据分析16

3.1润湿性分析.16

3.2微观形貌分析.17

3.3孔结构分析.18

结论.25 生物质纳米材料的结构和物理性能:http://www.youerw.com/cailiao/lunwen_205128.html