钙离子存在下海藻酸盐稀溶液的粘度性质

Effect of Ca^(2+) Concentration on the Viscosity of Dilute Alginate Solution

通过测定体系的粘度,研究了加入不同量的Ca2+到海藻酸钠稀溶液中所引起体系粘度的变化规律。考察了海藻酸钠浓度、温度、以及外加NaC l对粘度的影响。结果表明,在较高浓度(质量分数分别为0.125%和0.15%)时,随着Ca2+加入量的增大,海藻酸盐体系的粘度先降至一极小值,然后迅速增大,直至有凝胶状物质生成;在较低浓度(质量分数为0.075%)时,海藻酸盐体系的粘度则变化幅度不大;在15~35℃温度范围内,Inηrel-1/T具有良好的线性关系;NaC l的加入使体系相对粘度下降。FTIR和DSC结果表明,Ca2+与海藻酸盐发生了相互作用,所形成的海藻酸钙复合物的热稳定性比相应的海藻酸钠高。

The viscosity of dilute alginate solution as a function of Ca^2＋ concentration was studied by viscosity measurement. The effect of polymer concentration, temperature and NaCl on the viscosity was investigated. The results show that for 0. 125% and 0. 15% alginate solutions, the viscosities firstly declined to certain minimum values with increasing the amount of Ca^2＋ added, and then rapidly rised until gel occurred ; for a 0. 075% alginate solution, the viscosity slightly changed as the amount of Ca^2＋ increased; In ηrel- 1/T had a good linearity in the temperature range of 15 - 35 ℃ ; the viscosity decreased as NaCl was added. Thermal stability and the structure of calcium alginate complex were analyzed by means of DSC and FTIR.