木质素磺酸钙改性聚羧酸的研制及其保水性能

为解决工程上聚羧酸高效减水剂(PCE)对掺量敏感和容易出现离析泌水的问题,采用水溶液聚合法和复配法,以甲氧基聚乙二醇甲基丙烯酸酯(MPEGMA)、丙烯酸(AA)、木质素磺酸钙(CL)为原料,制备共聚型木质素磺酸钙改性聚羧酸高效减水剂(GCL-PCE)和复配型木质素磺酸钙改性聚羧酸高效减水剂(FCLPCE),研究了木质素磺酸钙用量对两者保水性等性能的影响,并与改性前的聚羧酸高效减水剂进行对比.通过FT-IR证明,GCL-PCE与FCL-PCE被成功制备,随着CL用量的增加,掺FCL-PCE和GCL-PCE的砂浆泌水率比总体呈先上升后下降的趋势,掺FCL-PCE的砂浆泌水率比均小于100%,保水性好,符合高效减水剂泌水率比≤100%的要求.当CL用量达10%,GCL-PCE掺量达0.2%时的减水率为23.16%;当CL用量相同时,GCL-PCE的减水分散作用较FCL-PCE更佳.

Preparation and Water Retention of Calcium Lignosulfonate Modified Polycarboxylate

In order to solve the sensitiveness of mixing amount and the easiness of bleeding of polycarboxylate superplasticizer（PCE）,methoxy polyethylene glycol methacrylate（MPEGMA）,acrylic acid（AA）,and calcium lignosulfonate were used to synthesize lignin-polycarboxylate copolymer superplasticizer（GCL-PCE） and ligninpolycarboxylate compounding superplasticizer（FCL-PCE） by aqueous solution polymerization and compounding.The effects of the dosage of lignin-polycarboxylate on their water-retaining property were studied,and then compared with that of the unmodified polycarboxylate superplasticizer.The results showed that GCL-PCE and FCLPCE were prepared through FT-IR successfully;with the increase of CL,the bleeding rate of the mortar with FCLPCE or GCL-PCE increased and then decreased,and all the bleeding rates of mortar with FCL-PCE were less than 100%,which showed good water-retaining property and met the requirement of high range water reducing agent that bleeding rate should be less than 100%;when the CL accounted for 10%,the water reducing rate reached 23.16% in the GCL-PCE dosage of 0.2%;when the same dosage of CL was added,GCL-PCE performed better in water-reducing and dispersion properties than FCL-PCE.