不同贮藏时间对CMC溶液流变特性的影响研究

摘要

羧甲基纤维素钠(CMC)属于离子型纤维素衍生物,具有独特的增稠、悬浮作用而在食品工业中得到广泛应用.CMC中由于存在纤维素酶,贮藏时间影响其流变行为.本文应用高级旋转流变仪通过稳态流动、应变扫描及频率扫描等实验详细研究了CMC不同贮藏时间对其流变特性包括零剪切粘度、粘度、粘度衰减及粘性模量、弹性模量、损耗正切等指标的影响,并从微观结构上进行解析.实验表明:CMC在贮藏过程中发生降解,使链段密度减少,与分子量变化作用相同,由于氢键等分子间作用力的减弱使其流变性质发生变化,并在贮藏4～5月后出现明显的变化.通过贮藏时间对CMC溶液流变特性的影响研究,掌握了其变化规律,这为CMC在食品工业上的应用与原料质量控制提供一定的参考依据.%CMC is one of the cellulose derivatives with unique effects of thickening and suspension,as is widely used in food industry.There exists cellulose enzyme which has effects on the rheological properties of CMC solutions.In this paper with advanced rheometer the effect of different storage time of CMC solution on its rehological properties including zero-shearing viscosity,viscosity,viscosity damping and viscous modulus,elastic modulus,tan (delta) is studied in a detailed way through experiments like steady flow,strain sweep and frequency sweep,meanwhile,the mechanism is elaborated from the point of microstructure.The results show that the degradation of CMC occurs duringits storage,which leads to the diminution of density of chain segment same with thechange of molecular weight and attenuates inter molecular force like hydrogen bond making its rheological properties change especially after storage of 4 ～ 5months.Through studying of effect of storagetime on the rheologicalproperties,the reference frame for theapplication on food industry and quality control of CMC is provided to a certain extent.