采用小角激光散射法测定了纤维素硫酸钠(NaCS)的分子量,考察了盐离子及其浓度对分子量测定的影响.结果表明,取代度分别为0.28,0.40,0.73的3个样品的分子量分别为879.8,593.5和226.9kDa,盐离子浓度为0.05~0.075mol/L时测定较准确,盐离子浓度为0~0.05mol/L时光散射强度精密度较低,不利于分子量测定,粘度变化较大,表明此时NaCS分子处于膨胀伸展状态,不利于光散射法测定分子量.
Molecular weight (Mw) of sodium cellulose sulfate (NaCS) was determined by using low angle laser light scattering in this work. The Mw values of three samples with the degree of substitution 0.28, 0.40 and 0.73 were 879.8, 593.5 and 226.9 kDa respectively. The effects of different salts and their concentrations on determination of Mw were also investigated. When the concentration of salts was in the range of 0.05--4).075 mol/L, the accuracy of determination was better. However, when the concentration was lower than 0.05 mol/L, accurate result was obtained hardly, and in this range, the molecules of NaCS were in expanded state and the viscosity of NaCS varied dramatically.