黄原胶与阴离子瓜尔胶复配溶液的流变特性研究

Studies on Rheological Properties of Complex Gum Solution with Xanthan and Anionic Guar

配制总质量分数为1%的黄原胶与瓜尔胶复配溶液,两者比例分别为0.1%∶0.9%,0.2%∶0.8%,0.3%∶0.7%,0.4%∶0.6%,0.5%∶0.5%,0.6%∶0.4%,0.7%∶0.3%,0.8%∶0.2%,0.9%∶0.1%。通过稳态流动、应变扫描、频率扫描以及动态黏弹性温度扫描与动态黏度温度扫描,观察复配比例对复配溶液的黏度特性随剪切速率及温度的变化情况,黏弹性随应变、频率及温度的变化情况。黄原胶与瓜尔胶通过分子间缠绕或者分子间次级键的相互作用起到增稠协同作用,说明两者复配有利于零剪切黏度、黏度及黏弹性能的增加。在低剪切区域与低频率区域主要呈现黄原胶的贡献,而在高剪切区域与高频率区则以瓜尔胶起主导作用。对复配溶液的频率扫描中G′大于G″,表现类固态的性质。另外,在5-90℃温度范围,G′〉G″,复配溶液表现出凝胶状态,呈完善的网络结构;同时,黏度随温度的升高而逐步降低,不存在构象转变温度。

On a basis of total concentration 1% with xanthan and anionic guar a series of mixed solutions are prepared, where the ratio between them are 0.1% ： 0.9%, 0.2% ： 0.8%, 0.3% ： 0.7%, 0.4% ： 0.6%, 0.5% ： 0.5%, 0.6% ： 0.4%, 0.7%：0.3%, 0.8%：0.2%, 0.9%：0.1% respectively. Through the experiments like steady flow, strain sweep, frequency sweep, dynamic viseo-elasticity and viscosity temperature sweep, we observe the viscosity characteristic of the mixed solution varies with shear rate and temperature, the visco-elastieity varies with oscillation strain, frequency and temperature. The synergies is formed as a result of entanglement or inter-action of secondary bond of inter-molecular between xanthan and guar. Therefore, the complex of them helps to increase the zero-shearing viscosity, viscosity and vis- co-elasticity obviously. At the same time, in the lower shearing or frequency area xanthan has main contribution to the solution while in the higher area gnat plays a chief role. Complex solution behaves the solid-like as G＇ is larger than G＂ in the frequency sweep. In addition, the solution appears the gelling state and have the perfect network structure as G＇〉 G＂ in the dynamic visco-elasticity temperature sweep from 5 ℃to 90 ℃, meawhile, the viscosity gradually reduces as the temperature rises showing there is no conformational transition temperature.