纳米纤维素晶体形态的流变学表征
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- 英文论文题名：Characterization of cellulose nanocrystal morphology by rheology method
- 论文作者：吴强 ; 李秀雯 ; 王静芳
- 英文论文作者：Qiang Wu ; Xiuwen Li ; Jingfang Wang ; College of Engineering ; Zhejiang Agricultural & Forestry University ; Key laboratory of wood science and technology
- 年：2016
- 作者机构：浙江农林大学工程学院;浙江省木材科学与技术重点实验室;
- 论文关键词：纳米纤维素晶体 ; 长径比 ; 流变学 ; 特性粘数
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第十七分会：流变学
- 语种：中文
- 分类号：O636.11;TB383.1
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第十七分会 ; 流变学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：171k
- 原文格式：D
- 会议级别：全国
摘要
纤维素纳米晶体(Cellulose Nano-Crystal,CNC)是从纤维素中提取的一种直径在5-20nm,长度在100nm到几个微米的棒状晶体,在纳米增强材料与功能材料领域有重要应用价值~([1])。长径比为CNC最重要的性能指标,目前主要通过电镜显微观察统计法表征,该方法直观可见,但存在着测量工作量大、周期长、统计数据有随机性等不足。本研究采用乌氏粘度计考察了不同CNC表面电荷密度与外加盐(NaCl)含量对CNC悬浮液特性粘数的影响,并通过Simha模型~([2,3])拟合了CNC的长径比;研究结果表明,随着NaCl浓度增加(或者CNC表面电荷密度下降),CNC悬浮液稳定性下降,特性粘数出现了先降低后上升的变化,这主要是少量NaCl屏蔽CNC表面的离子双电层,而过量NaCl促使CNC聚集所致。在一定CNC表面电荷密度与NaCl含量下,通过流变法所得的CNC长径比与透射电镜(TEM)统计结果非常接近,表明流变法是一种表征CNC长径比的可行方法,且在测试时间、表征条件和统计权重上有明显优势。
The objective of this study is to use rheology as a simple method for cellulose nano-crystal(CNC)morphology characterization.In order to give accurate CNC morphology,the influence of NaCl concentrations on the stability,effective diameter and rheological behavior were investigated by dynamic light scattering and Ubbelohde viscometer.With NaCl concentration increasing,the stability of CNC suspensions decreased,while the effective diameter and intrinsic viscosity first decreased and then increased.This phenomenon was attributed to screening effect of double electric layers on CNC at lower NaCl content,and promoting CNC aggregation at higher NaCl content.CNC aspect ratio calculated by Simha model was very close to that of TEM statistical results,which indicated that the rheological method is a viable method for CNC aspect ratio characterization.
The objective of this study is to use rheology as a simple method for cellulose nano-crystal(CNC)morphology characterization.In order to give accurate CNC morphology,the influence of NaCl concentrations on the stability,effective diameter and rheological behavior were investigated by dynamic light scattering and Ubbelohde viscometer.With NaCl concentration increasing,the stability of CNC suspensions decreased,while the effective diameter and intrinsic viscosity first decreased and then increased.This phenomenon was attributed to screening effect of double electric layers on CNC at lower NaCl content,and promoting CNC aggregation at higher NaCl content.CNC aspect ratio calculated by Simha model was very close to that of TEM statistical results,which indicated that the rheological method is a viable method for CNC aspect ratio characterization.
引文
[1]Habibi Y.;Lucia LA.;Rojas 0 J.Chem.Rev.2011,110:3479.
[2]Boluk Y.;Lahiji R.;Zhao L.;McDermott.M T.Colloids Surf.A.2011,377:297.
[3]Simha R.J.Phys.Chem.1940,44:25.
[2]Boluk Y.;Lahiji R.;Zhao L.;McDermott.M T.Colloids Surf.A.2011,377:297.
[3]Simha R.J.Phys.Chem.1940,44:25.