酸析木素的接枝磺化改性及减水增强作用

Graft Sulfonation and Water Reducing-Performance Strengthening Effect of Acid Precipitation Lignin

通过接枝反应在酸析木素上引入活性分子链,提高其磺化活性,得到接枝磺化酸析木素;采用红外光谱研究了接枝磺化酸析木素的分子结构,并对其减水增强性能进行了研究.结果表明：接枝磺化酸析木素分子中含有较多的磺酸基和酚羟基,分子中的甲氧基被活性基团所取代,使产物具有更大的活性;接枝磺化酸析木素以70%和60%的用量（占减水剂总掺量的百分数）与木钙复配,可分别得到减水剂MCL1和MCL2,当水灰比为0.28、掺量为0.6%时,掺复配产品的水泥净浆流动度达230mm以上,掺量为0.8%时,掺复配产品的水泥净浆初凝时间延长50～80min,终凝时间延长6～7h;掺MCL1的砂浆的减水率为25.5%,7天和28天抗压强度比分别为135%和123%,其对水泥的减水增强作用与萘系高效减水剂FDN相当.

The graft sulfonation of acid precipitation lignin was carried out by introducing active groups to improve the sulphanating activity. The structure of the obtained graft sulfonation lignin was then investigated by IR, and the water reducing-performance strengthening ability was also discussed. The results show that （1） many sulfonic groups and phenylic .hydroxyl groups are introduced into the graft sulfonation lignin, and the methoxyl groups are substituted by active groups, thus improving the activity of the produced lignin, （2） as to the two superplasticizers （MCL1 and MCL2） prepared by mixing the graft sulfonation lignin with calcium lignosulfonate in the lignin contents of 70% and 60%, the fluidity of the cement paste with 0.6% combined products is more than 230 mm when the water to cement ratio reaches 0.28, and the initial setting time and final setting time of the cement paste with 0. 8% combined products are respectively 50 ～ 80min and 6 -7h retarded; and （3） the water-reducing ratio of the mortar with 0.8% MCL1 is 25.5%, and the 7-day and 28-day compressive strength ratios are respectively 135% and 123%, which means that the water reducing-performance strengthening ability of the combined product is similar to that of naphthalene series superplasticizer FDN.