温度、浓度对水/乙醇混合溶剂中壳聚糖溶液黏度的影响

研究了溶解于水/乙醇混合溶剂中的壳聚糖溶液黏度随温度和浓度的变化规律。混合溶剂中,乙醇是壳聚糖的不良溶剂,而水是壳聚糖的良溶剂,将乙醇与水按一定比例混合,再加入1%的乙酸,配制成水/乙醇混合溶剂。实验使用乌氏黏度计测量溶液黏度,通过分析黏度随温度、浓度的变化规律,揭示了混合溶剂对壳聚糖溶液黏度的影响规律。研究发现,壳聚糖溶液黏度随着温度的升高而降低;恒定温度,壳聚糖溶液黏度随浓度的增加而增加。而随着温度的升高,壳聚糖在良溶剂中产生的增比黏度变化率要比其在不良溶剂中高;随着浓度的增加,壳聚糖溶液产生的增比黏度的变化率也相应增加。当浓度极稀时,壳聚糖溶液的(ηsp/C)/C曲线会出现反常现象——体系黏度随着浓度的减小而急剧上升。

Effect of Temperature and Concentration on the Viscosity of Chitosan Solution in Water/Ethanol Mixed Solvent

The change low of viscosity of chitosan solution in water/ethanol mixed solvent with the temperature and concentration was investigated .Water with 1％ (volume) acetic acid added was used as the good solvent .Ethanol ,an organic solvent ,was the poor solvent .Different proportion of ethanol volume mixed with water solution was acted as poor solvents which could provide solubility of regular difference ,respectively .Ubbelohde viscometer was used as the viscosity measuring instrument . And the change low of viscosity of chitosan solution with temperature and concentration was measured .The experimental results showed that the viscosity of chitosan solution reduced with the increasing of temperature . And it would be increased with the increasing of concentration ,following the constant temperature .When chitosan solution was in good solvent ,the change rate of specific viscosity was higher than that in poor solvent .With the increasing of concentration ,the change rate of specific viscosity was increased correspondingly .In the extremely dilute concentration ,the(ηsp/C)/C curve of chitosan solution would appear abnormal phenomenon where the viscosity of chitosan solution increased sharply with the decreasing of concentration .