梳形支化结构聚羧酸高性能减水剂的合成.pdfVIP

学兔兔 全国中文核心期刊 杆 建巍 藤形支化结构聚羧酸高性雒濂水剂硇合成 杨勇，冉千平，刘加平，张志勇，缪昌文 (江苏博特新材料有限公司，高性能土木工程材料国家重点实验室，江苏省建筑科学研究院有限公司，江苏 南京 210008) 摘要：以支化活性大单体与丙烯酸进行水溶液自由基共聚，合成了梳形支化结构聚羧酸高性能减水剂。考察了引发体系、单体 投料比及滴加时间、链转移剂种类及用量、聚合浓度等合成条件对减水剂分散性能的影响。确定了最佳合成条件为：采用L_抗坏血酸 与双氧水的氧化还原引发体系，L一抗坏血酸的用量为1％；丙烯酸(AA)与大单体的投料摩尔比为4：l，AA的滴加时间为3h：链转移剂 用量为单体总摩尔数的2．O％；聚合浓度为50％。通过凝胶渗透色谱测得合成减水剂的重均分子质量为47 500，DAM大单体的转化率 为89．6％。与常规结构聚羧酸减水剂相比，所制备的梳形支化结构聚羧酸减水剂具有较高的减水率和较好的坍落度保持能力。 关键词：聚羧酸减水剂；支化；大单体；共聚 中图分类号：TU528．042．2 文献标识码：B 文章编号：1001—702X(2011)07～0054—04 Synthesis of comb-branched polycarboxylate superplasticizers YANG yo ，RAN Qianping，LIU Jiaping，ZHANG Zhiyong，MIA0 Changwen (Jiangsu Bote New Materials Co．Ltd．，State Key Laboratory of High Performance Civil Engineering Materials， Jiangsu Research Institute of Building Science Co．Ltd．，Naming 210008，Jiangsu，China) Abstract：The polycarboxylate superplasticizers were synthesized by the free radical copolymerization of dendritic activated and acrylic acid in water．The effects of various synthesis conditions(initiation system，monomer feed ratio and drop— ping time，type and amount of chain transfer agents，and polymer concentration)on the dispersibility of polycarboxylate superplasti— cizers were studied．The optimal reaction conditions were using the L-ascorbic acid and Hydrogen Peroxide(H20~as initiators，the dosages of L-ascorbic acid and chain transfer agents were 1％ and 2％ of monomers．The mol ratio of acrylic acid(AA)and was 4：1，AA dropping for 3 h．The concentration of polymerization was 50％．Gel permeation chromatography showed that the weight average molecule w