Surface only modification of bacterial cellulose nanofibres with organic acids
Surface only modification of bacterial cellulose nanofibres with organic acids
复制标题
DOI：
10.1007/s10570-011-9525-z
复制
发表时间：
2011-06-01
期刊：
影响因子：
5.7
通讯作者：
Bismarck, Alexander
中科院分区：
文献类型：
--
作者：
Lee, Koon-Yang;Quero, Franck;Bismarck, Alexander
使用乙酸、己酸或十二烷酸的酯化反应仅对细菌纤维素（BC）纳米纤维的表面进行改性。该反应使BC纳米纤维的极其亲水的表面变得疏水。 BC的疏水性随着用于酯化反应的有机酸的碳链长度的增加而增加。流动（zeta-）电位测量显示等电点略有变化，酯化反应后还观察到zeta（平台）下降。这是由于BC与有机酸的酯化导致酸性官能团的损失和疏水性的增加。开发了一种基于氢/氘交换的方法来评估纯BC和改性BC表面羟基的可用性。改性BC板的热降解温度随着所用有机酸碳链长度的增加而降低。这被认为是酯化反应的直接结果，由于纳米纤维之间有效氢键数量的减少，酯化反应显着降低了纳米纤维的堆积效率。
Bacterial cellulose (BC) nanofibres were modified only on their surface using an esterification reaction with acetic acid, hexanoic acid or dodecanoic acid. This reaction rendered the extremely hydrophilic surfaces of BC nanofibres hydrophobic. The hydrophobicity of BC increased with increasing carbon chain length of the organic acids used for the esterification reaction. Streaming (zeta-) potential measurements showed a slight shift in the isoelectric point and a decrease in zeta(plateau) was also observed after the esterification reactions. This was attributed to the loss of acidic functional groups and increase in hydrophobicity due to esterification of BC with organic acids. A method based on hydrogen/deuterium exchange was developed to evaluate the availability of surface hydroxyl groups of neat and modified BC. The thermal degradation temperature of modified BC sheets decreased with increasing carbon chain length of the organic acids used. This is thought to be a direct result of the esterification reaction, which significantly reduces the packing efficiency of the nanofibres because of a reduction in the number of effective hydrogen bonds between them.