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制备了以羧甲基纤维素硝酸酯(CMCN)为胶凝剂的硝基甲烷(NM)凝胶,系统研究了CMCN修饰基团比例变化所引起NM/CMCN凝胶流变性能差异性的规律.探讨了凝胶的形成机理并采用线性的流变学方法研究了NM/CMCN凝胶的屈服性、触变性、蠕变性、温敏性等动态粘弹性质,分别利用Herschel-Bulkley模型、Burger模型、Carreau-Yasuda模型、Andrade-Eyring模型对凝胶的流动曲线、蠕变曲线、频率曲线和温敏曲线进行了数据拟合.研究发现,NM/CMCN凝胶是由CMCN大分子链上两亲性基团与有机小分子基团间通过分子链间疏水键、氢键等非共价键相互作用形成的一种物理交联网络型凝胶.凝胶的非牛顿系数n均小于0.60.随着硝酸酯基团含量的减少,NM/CMCN凝胶的结构强度变弱,表现出屈服应力逐渐减小、触变恢复性逐渐增强、粘性与弹性柔量均减小但粘性柔量比例增加的趋势;凝胶的弹性响应性逐渐减弱而粘性响应性渐强,内耗也逐渐增大;凝胶的活化能总体上增大,温度稳定性变弱.
The nitromethane (NM) gel with carboxymethylcellulose nitrate (CMCN) as gelling agent was prepared and the difference of the rheological properties of NM / CMCN gel was systematically investigated. The formation mechanisms of gels were discussed and the dynamic viscoelastic properties of NM / CMCN gels such as yield, thixotropy, creep and temperature sensitivity were investigated by using the linear rheological method. The viscoelastic properties of NM / CMCN gels were investigated by Herschel-Bulkley model, Burger model, Carreau-Yasuda model and Andrade-Eyring model were used to fit the flow curves, creep curves, frequency curves and temperature-sensitive curves of the gel.The results showed that NM / CMCN gel was composed of CMCN macromolecule chains A physically crosslinked network gel formed by the non-covalent interaction between amphiphilic groups and small organic molecules through the non-covalent interaction between hydrophobic and hydrogen bonds in the molecular chains, etc. The non-Newtonian coefficients n of gels are all less than 0.60 With the decrease of nitrate content, the structural strength of NM / CMCN gel became weaker, the yield stress decreased, the thixotropy recovery gradually increased, and the viscosity and elastic compliance decreased, but the viscosity ratio Increasing trend; gel elastic response gradually weakened Responsive viscosity crescendo, internal friction increases gradually; gel increases overall activation energy, temperature stability becomes weaker.