Surface modification of bacterial cellulose nanofibers for property enhancement of optically transparent composites: Dependence on acetyl-group DS
Surface modification of bacterial cellulose nanofibers for property enhancement of optically transparent composites: Dependence on acetyl-group DS
复制标题
DOI：
10.1021/bm070113b
复制
发表时间：
2007-06-01
影响因子：
6.2
通讯作者：
Yano, Hiroyuki
中科院分区：
文献类型：
--
作者：
Ifuku, Shinsuke;Nogi, Masaya;Yano, Hiroyuki
将细菌纤维素（BC）纳米纤维乙酰化，以提高丙烯酸树脂的光学透明复合材料的性能与纳米纤维增强。得到了一系列从取代度（DS）0到1.76乙酰化的BC纳米纤维。X-射线衍射分析表明，乙酰化从BC纳米纤维的表面到纤维的芯部进行，扫描电子显微镜图像显示，体积庞大的乙酰基增加了纳米纤维的体积。由于乙酰化降低了纤维素的折射率，由63%BC纤维组成的复合材料的规则透射率得到改善，并且由于纤维增强而在580 nm处的劣化被抑制到仅3.4%。乙酰化的纳米纤维改变了它们的表面性质，并降低了复合材料的水分含量约三分之一的未处理的复合材料，虽然过度乙酰化增加吸湿性。此外，发现乙酰化可将BC片的热膨胀系数从3 x 10（-6）降低至低于1 x 10（-6）1/K。
Bacterial cellulose (BC) nanofibers were acetylated to enhance the properties of optically transparent composites of acrylic resin reinforced with the nanofibers. A series of BC nanofibers acetylated from degree-of-substitution (DS) 0 to 1.76 were obtained. X-ray diffraction profiles indicated that acetylation proceeded from the surface to the core of BC nanofibers, and scanning electron microscopy images showed that the volume of nanofibers increases by the bulky acetyl group. Since acetylation decreased the refractive index of cellulose, regular transmittance of composites comprised of 63% BC nanofiber was improved, and deterioration at 580 nm because of fiber reinforcement was suppressed to only 3.4%. Acetylation of nanofibers changed their surface properties and reduced the moisture content of the composite to about one-third that of untreated composite, although excessive acetylation increased hygroscopicity. Furthermore, acetylation was found to reduce the coefficient of thermal expansion of a BC sheet from 3 x 10(-6) to below 1 x 10(-6) 1/K.