Abstract：
Tailoring the properties of cellulose aerogel beads was investigated in the present study by using weak organic acids as coagulants. Three different weak acids were specifically chosen, acetic acid, lactic acid and citric acid. For comparative studies, a strong acid, hydrochloric acid was examined. The production of aerogel beads by conventional dropping technique was controlled and optimized for weak acids. Aerogels were characterized by density analyses, scanning electron microscopy, nitrogen adsorption-desorption analysis, X-ray powder diffractometry and IR spectroscopy. In common, all the aerogel beads showed interconnected nanofibrillar network, high specific surface area, high pore volume, high porosity and meso- and macroporous structure. In particular, when the weakest acid (acetic acid) was used as coagulant in the regeneration bath, the lowest shrinkage was observed. As a result, the cellulose aerogel beads produced from acetic acid showed the highest values of specific surface area (423 m2·g-1) and pore volume (3.6 cm3·g-1). The porous structure can be tuned by the choice of regeneration bath having either strong acid or high concentration of weak acid. The aerogel beads were pure and showed cellulose II crystallinity. Hence this study paves an alternative path way to tailor the properties of cellulose aerogel beads.
摘要：
在本研究中，通过使用弱有机酸作为凝结剂来研究纤维素气凝胶珠的性能。特别选择了三种不同的弱酸，乙酸,乳酸和柠檬酸。对于比较研究，一种强酸，盐酸被检查。针对弱酸，对常规滴落技术生产气凝胶珠进行了控制和优化。气凝胶的特征在于密度分析，扫描电子显微镜，氮气吸附-解吸分析，X射线粉末衍射和红外光谱。在共同的,所有的气凝胶珠都显示出相互连接的纳米纤丝网络，高比表面积，高孔隙体积,高孔隙率和中孔和大孔结构。特别是,当在再生浴中使用最弱的酸（乙酸）作为促凝剂时，收缩率最低。因此,由乙酸生产的纤维素气凝胶珠显示出最高的比表面积（423m2·g-1）和孔体积（3.6cm3·g-1）。多孔结构可以通过选择具有强酸或高浓度弱酸的再生浴来调节。气凝胶珠粒是纯的并且显示纤维素II结晶度。因此，这项研究为定制纤维素气凝胶珠的特性铺平了一条替代途径。
