关键词: 木质素磺酸镁, 分子量, 吸附, 表面电位

Abstract:

The structural characteristic and surface physicochemical properties of bagasse magnesium lignosulfonate(MLS) are investigated by means of GPC,UV,IR and ¹³C NMR. Four purified MLS fractions with different molecular weights were obtained by fractionation using ultrafiltration and analyzed. The results show that MLS contained more syringin phenyl propane, and less guaiacol phenyl propane comparing with woody calcium lignosulfonate (CLS). The average molecular weight of MLS and the content of sulfonic and phenolic hydroxyl group are lower than that of CLS. As the increasing of molecular weight of MLS, the mass fraction of sulfonic and phenolic hydroxyl group increases. The relative molecular weight distribution and the content of sulfonic and phenolic hydroxyl group are the main affecting factors on the adsorption characteristic of MLS on cement-water interface and the surface charge of cement particle absorbing MLS. With the increasing of molecular weight of MLS, the Zeta potential absolute value of cement particle increases. The adsorbing amount and the Zeta potential absolute value of the surface of cement particle adsorbing MLS fraction with the molecular weight more than 50000, is similar to that of CLS, and its adsorption isotherm follows Langmuir type.

Key words: 木质素磺酸镁, 分子量, 吸附, 表面电位