高等学校化学学报 ›› 2015, Vol. 36 ›› Issue (10): 2034.doi: 10.7503/cjcu20150528

• 高分子化学 • 上一篇    下一篇

水在纤维素水凝胶中的存在状态及对纤维素结晶的影响

陈风, 刘正英, 华笋, 阚泽, 杨鸣波()   

  1. 四川大学高分子科学与工程学院, 高分子材料工程国家重点实验室, 成都 610065
  • 收稿日期:2015-07-08 出版日期:2015-10-10 发布日期:2015-09-14
  • 作者简介:联系人简介: 杨鸣波, 男, 博士, 教授, 主要从事高分子材料成型加工方法及工艺、 聚合物成型加工基础理论和聚合物材料与制品破坏特性研究. E-mail:yangmb@scu.edu.cn
  • 基金资助:
    国家重点基础研究发展计划(批准号: 2012CB025902)资助

States of Water in Cellulose Hydrogels and Influence on the Crystallization of Cellulose

CHEN Feng, LIU Zhengying, HUA Sun, KAN Ze, YANG Mingbo*()   

  1. College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China
  • Received:2015-07-08 Online:2015-10-10 Published:2015-09-14
  • Contact: YANG Mingbo E-mail:yangmb@scu.edu.cn

摘要:

制备了高度水合状态的纤维素凝胶, 研究了水在凝胶中的存在状态及其对纤维素结晶的影响. 结果表明, 水在纤维素水凝胶中存在非冻结水、 可冻结水和自由水3种状态. 非冻结水饱和含量为一般纤维素吸附水中不可冻结水的5倍以上, 高达1.6 g/g. 纤维素在水合状态下结晶受到抑制, 随着水含量的减小, 结晶会趋于完善. 在环境温度下, 当纤维素中只存在非冻结水时, 其与纤维素分子链间氢键作用力不稳定, 对纤维素结晶抑制作用较弱, 纤维素结晶比较完善, 导致纤维素断裂时表现为脆性断裂. 水介质的引入有望为纤维素的利用开发提供一种新的思路.

关键词: 纤维素, 结合水, 氢键, 结晶

Abstract:

A study inspired by biosynthesis of cellulose in higher plant was made on an attempt to investigate the state of water in cellulose hydrogels and its influence on the crystallization of cellulose. The differential scanning calorimetry(DSC) results indicate that there are 3 types of water in cellulose hydrogels: nonfreezing water, freezing bound water and free water. The ratio of the nonfreezing water to dry cellulose in the hydrogels is about 1.6 g/g, 5 times more than the adsorbed water in dry cellulose. In such a highly hydrated state, the aggregation and crystallization of cellulose are inhibited, the lower the water content, the completer the crystallization of cellulose, which is characterized by X-ray diffraction(XRD), polarizing optical microscope(POM) and scanning electron microscopy(SEM). It is suggested that the little inhibition effect of nonfreezing water on the crystallization is due to the instability of the hydrogen bond between the water and cellulose. The results demonstrate the high content of nonfreezing water in cellulose hydrogels.

Key words: Cellulose, Bound water, Hydrogen bond, Crystallization

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