聚羧酸系高效减水剂地制备及性能

密级：公开

聚羧酸系高效减水剂的制备与性能Preparation and Properties of Polycarboxylic Acid Type Water-reduce

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2012年 6 月

摘要

聚羧酸系减水剂具有高减水率和控制坍落度损失的优点，但不同结构的聚羧酸减水剂其减水性能和坍落度保持性有很大差别，因此研究和开发具有特定结构的新型聚羧酸减水剂及结构与性能的关系受到国外的广泛关注。

本文从聚羧酸减水剂的结构入手，通过分子设计，以两步合成法制得了聚羧酸系减水剂。实验采用聚乙二醇单甲醚与甲基丙烯酸，通过直接酯化合成制备出聚乙二醇单甲醚甲基丙烯酸酯(大单体)，然后将聚乙二醇单甲醚甲基丙烯酸酯与甲基丙烯酸、甲基丙烯磺酸钠等单体在水溶液中经过自由基聚合，得到聚羧酸减水剂。

研究第一步大单体合成的最佳条件，采用碱滴定方法来评价酯化反应的酯化率，并用其来衡量催化剂用量、阻聚剂用量、酯化时间和酯化温度对酯化反应的影响。得到最佳合成条件为聚乙二醇单甲醚与甲基丙烯酸的反应摩尔比为1：2.5，催化剂加入量为原料总量的3%，阻聚剂加入量为甲基丙烯酸量的2.8%，反应温度为130℃，反应时间为6h，加入带水剂为原料总量的30%。第二步合成最终产物的最佳条件，通过测得未反应双键的量讨论反应物摩尔比、甲基丙烯磺酸钠的量及保温时间对减水剂的影响。最佳条件为自制大单体聚乙二醇单甲醚甲基丙烯酸酯与甲基丙烯酸的摩尔比为3.3：1，引发剂的量为单体总质量的2%并且配制成10%的水溶液进行滴加，自制大单体与甲基丙烯酸的共聚混合物配制成40%的溶液进行滴加。反应温度为85℃，甲基丙烯磺酸钠的加入量为单体总质量的3.2%，保温时间为2h。

实验结果制得褐色固态中间产物大单体及黄色透明液体的减水剂，经红外检测证明产物含有大单体和减水剂特征基团，说明本实验已制备出目的减水剂。通过对水泥性能的简单测试评价自制的聚羧酸系减水剂的性能。

关键词:聚乙二醇单甲醚甲基丙烯酸酯；聚羧酸高效减水剂；合成；红外表征

Abstract

Polycarboxylic water-reducer exhibits all excellent ability of water-reducing and controlling slump losses. However, polycarboxylic acid type water-reducer with different structures has different water-reducing performance and slump-keeping capability. Research on the structure of polycarboxylic acid water-reducer and the connection between the structure and the properties have gotten wide-spread attention at home and abroad.

In this thesis, polycarboxylic type water-reducer was synthesized by the method of two steps, and the molecule frame of the chemical structure of high performance water-reducers was designed. The experiment using polyethylene glycol single methyl ether and methyl methacrylate, through the direct esterification synthesis polyethylene glycol single methyl ether methylacrylic acid ester, and then will polyethylene glycol single methyl ether methylacrylic acid ester and methyl methacrylate, methyl propylene sulfonic acid sodium etc monomer in water solution after radical polymerization, get together polycarboxylic type water-reducer.

The first step in the best condition of big monomer synthesis, use the alkali titration method to evaluate the esterification of esterification rate, and use it to measure catalyst dosage, resistance gather agent, and esterification time and esterification temperature on the effect of esterification reaction. Get the best synthesis conditions for polyethylene glycol single methyl ether and methyl methacrylate reaction molar ratio of 1:2.5, catalyst to 3% of the total amount as raw material, resistance to join together to methyl methacrylate agent is the amount of 2.8%, and the reaction temperature 130℃, reaction time for 6h, join water-carrying as raw material to 30% of the total. The optimum condition of the second stept, by measured the amount of double not reaction discuss the mole ratio of reactants, methyl propylene sulfonic acid sodium quantity and holding time on the influence of the water-reducer. The best conditions is homemade big monomer polyethylene glycol single methyl ether methylacrylic acid ester and methacrylic acid mole ratio of 3.3 :1, the amount of initiator for 2% of the total weight of monomer and made into 10% of the solution for adding, homemade big monomer and methyl methacrylate copolymerization of mixture made into 40% of the solution for adding. Reaction temperature 85℃, methyl propylene sulfonic acid sodium addition amount to 3.2% of the total weight of monomer, heat preservation time is 2h.

The experiment obtained brown solid intermediate and yellow viscous water reducing agent, it’s proved by infrared detection that the products contains macromer and characteristic