新型刺激响应性纤维素基含能凝胶的流变性能

研究了以不同基团含量的羧甲基纤维素硝酸酯(CMCN)为胶凝剂的含能凝胶细微结构与流变行为的关系.探讨了凝胶的形成机理,并采用线性的流变学方法研究了凝胶的屈服性、触变性、蠕变性及温敏性等动态黏弹性质,分别利用Herchel-Bulkley模型、Burger模型及Carreau-Yasuda模型对凝胶的流动曲线、蠕变曲线和频率曲线进行了数据拟合.研究发现,CMCN凝胶是由其分子结构上两亲性基团通过分子链间氢键及疏水键等非共价键相互作用形成的一种结构均匀的物理交联网络型凝胶.凝胶的非牛顿系数n均小于0.5.随着亲水性羧酸基团含量的增加,凝胶的屈服应力逐渐增大,触变恢复性逐渐增强,弹性与黏性柔量均减小,但其比值增加,蠕变的黏性响应性逐渐减弱而弹性响应性逐渐增强.凝胶的温敏性变化有一个力学松弛转变区,随着羧酸基团含量的增加,松弛转变区愈发明显,凝胶的温敏性也逐渐增强.

Rheological Properties of New Stimuli-responsive Energetic Gels

The relationships between the microstructure and the rheological behavior of energetic gels prepared by carboxymethyl cellulose nitrate(CMCN) of different content group as a gelator were investigated.The yield stress,thixotropy,creep and thermosensitivity of energetic gels were investigated by linear rheological methods and the gel mechanism was discussed.The flow data,creep data and angular frequency data of gels were fitted by Herschel-Bulkley model,Burger model and Carreau-Yasuda model,respectively.The experimental results show that CMCN gel is a physical gel with a relative homogeneous crosslinking network structure which is formed by non-covalent interaction of interchain hydrogen bonds and hydrophobic bonds on the group of amphiphilic CMCN.The non-Newton coefficients n of CMCN gels are all less than 0.5.With the increase of the content of hydrophilic carboxylic group,the yield stress and thixotropy recovery of gels increase gradually.The elastic compliance and viscous compliance of gel decrease while the ratio between them increase.The creep viscous responsivity decrease while elastic responsivity increase.The thermosensitivity of gels have a mechanical relaxation transition region which become more clearly with the increase of the content of carboxylic group,and thermosensitivity of gels increase.