Contribution of different state of adsorbed water to the sub-T-g dynamics of cellulose
Contribution of different state of adsorbed water to the sub-T-g dynamics of cellulose
复制标题
不同状态的吸附水对纤维素亚T-g动力学的贡献
DOI：
10.1016/j.carbpol.2019.01.087
复制
发表时间：
2019
影响因子：
11.2
通讯作者：
Chen Lin
中科院分区：
文献类型：
--
作者：
Zhao Hao;Chen Zhen;Du Xianfeng;Chen Lin
采用介电光谱与LF-NMR相结合的方法研究了不同吸附状态的水对纤维素亚热动力学的贡献。利用LF-NMR测定了纤维素中吸附水的分布和水化状态，并在此基础上详细讨论了不同吸附水状态在典型二次介质弛豫中的作用。这些弛豫的动态特性的变化表明，潮湿纤维素中存在三种状态的结合水，包括紧密结合水、不可冷冻的松散结合水和可冷冻的松散结合水。研究发现，不同状态的吸附水对这些弛豫的贡献有明显的差异，而特定状态的结合水在不同弛豫中所起的作用也不同。对于含水量非常高的纤维素，还观察到由于界面冰状水的动力学而产生的额外松弛。
The contribution of different states of adsorbed water to the sub-Tgdynamics of cellulose was investigated by means of dielectric spectroscopy in couple with LF-NMR. The distribution and hydration state of adsorbed water in cellulose were determined by LF-NMR, based on which the role that different state of adsorbed water plays in typical secondary dielectric relaxations is discussed in detail. The variation of the dynamic characteristics of these relaxations suggested that three states of bound water present in moist cellulose, including tightly bound, non-freezable loosely bound, and freezable loosely bound water. It was discovered that different state of adsorbed water has obviously different contribution to these relaxations and the role that a certain state of bound water plays in different relaxations also varies. For cellulose with very high moisture content, an additional relaxation due to the dynamics of interfacial ice-like water was also observed.