聚羧酸系高性能保坍剂的研究
发布时间：2018-09-18 19:13
【摘要】：随着我国基础设施工程建设的大规模发展，我国对商品混凝土的质量要求越来越严格。目前在高性能混凝土中，聚羧酸系高性能减水剂的使用非常广泛。聚羧酸系减水剂因其无毒、环保、减水率高等特点受到广泛关注，今后的应用前景将更加广泛。在聚羧酸减水剂的应用过程中遇到了许多工程难题，最为突出的就是因水泥、混合材、砂石含泥等质量问题相应带来了掺聚羧酸高效减水剂的混凝土坍落度损失加快，影响到了聚羧酸高效减水剂的应用和发展。 本文在聚羧酸减水剂合成技术的基础上，通过合理的分子结构设计，采用甲基烯丙基聚氧乙烯醚（TPEG）与丙烯酸（AA），在加入复合分子量调节剂、改性引发剂的条件下共聚，，开发出性能优异的聚羧酸系高性能保坍剂。 通过单因素分析探讨反应时间、反应温度、改性引发剂用量、丙烯酸与甲基烯丙基聚氧乙烯醚的摩尔比（酸醚比）以及复合分子量调节剂对保坍剂性能的影响。运用正交试验设计，发现各个因素协同作用对保坍剂性能的影响较大，得出各个因素对合成聚羧酸保坍剂性能的影响由大到小依次为：酸醚比＞复合分子量调节剂＞改性引发剂＞反应温度＞反应时间。并得到优化后的最佳反应条件为：反应温度为60℃、反应时间为2h、n(AA):n(TPEG)为1.5:1、改性引发剂用量为0.84%和复合分子量调节剂用量为0.28%。并通过改变单体种类，发现不同单体对保坍剂性能的影响较大。 通过混凝土坍落度及其经时损失试验、抗压强度试验、水泥适应性试验和贮存稳定性试验得出：掺加研究的聚羧酸保坍剂90min后坍落度和扩展度基本无损失，且自制聚羧酸保坍剂对混凝土的早期强度没有影响，能够提高混凝土的后期强度，并与武汉市市售的大部分水泥的适应性良好，该聚羧酸保坍剂不缓凝且有较好的贮存稳定性，给混凝土工程带来了良好的施工条件。 运用红外光谱等手段对所研究的聚羧酸保坍剂的分子结构进行表征，结合合成试验所用的原料得到聚羧酸保坍剂的理想分子结构，并从微观结构上探讨了聚羧酸保坍剂的空间位阻效应的主要作用机理。
[Abstract]:With the large-scale development of infrastructure construction in China, the quality requirements of commercial concrete are becoming more and more strict. At present, polycarboxylic acid series high performance water reducer is widely used in high performance concrete. Polycarboxylic acid superplasticizer is widely concerned because of its nontoxic, environmental protection and high water reducing rate, and its application prospect will be more extensive in the future. In the application of polycarboxylic acid superplasticizer, many engineering problems have been encountered. The most outstanding problem is that the slump loss of concrete mixed with polycarboxylic acid superplasticizer is accelerated due to the quality problems such as cement, mixing material, sand and stone, etc. The application and development of polycarboxylic acid superplasticizer are affected. On the basis of the synthesis technology of polycarboxylic acid water reducer and reasonable molecular structure design, the copolymerization of methyl allyl polyoxyethylene ether (TPEG) and acrylic acid (AA),) was carried out under the condition of adding compound molecular weight regulator and modifying initiator. A high performance polycarboxylic acid slump retention agent was developed. The effects of reaction time, reaction temperature, amount of modified initiator, molar ratio of acrylic acid to methallyl polyoxyethylene ether (acid ether ratio) and complex molecular weight modulator on the properties of slump retention agent were studied by single factor analysis. By using orthogonal test design, it is found that the synergistic effect of various factors has a great effect on the performance of the anti-collapse agent. The effects of various factors on the properties of the synthetic polycarboxylic acid slump retention agent were obtained as follows: acid / ether ratio > complex molecular weight regulator > modified initiator > reaction temperature > reaction time. The optimum reaction conditions were obtained as follows: the reaction temperature was 60 鈩
本文编号：2248850
[Abstract]:With the large-scale development of infrastructure construction in China, the quality requirements of commercial concrete are becoming more and more strict. At present, polycarboxylic acid series high performance water reducer is widely used in high performance concrete. Polycarboxylic acid superplasticizer is widely concerned because of its nontoxic, environmental protection and high water reducing rate, and its application prospect will be more extensive in the future. In the application of polycarboxylic acid superplasticizer, many engineering problems have been encountered. The most outstanding problem is that the slump loss of concrete mixed with polycarboxylic acid superplasticizer is accelerated due to the quality problems such as cement, mixing material, sand and stone, etc. The application and development of polycarboxylic acid superplasticizer are affected. On the basis of the synthesis technology of polycarboxylic acid water reducer and reasonable molecular structure design, the copolymerization of methyl allyl polyoxyethylene ether (TPEG) and acrylic acid (AA),) was carried out under the condition of adding compound molecular weight regulator and modifying initiator. A high performance polycarboxylic acid slump retention agent was developed. The effects of reaction time, reaction temperature, amount of modified initiator, molar ratio of acrylic acid to methallyl polyoxyethylene ether (acid ether ratio) and complex molecular weight modulator on the properties of slump retention agent were studied by single factor analysis. By using orthogonal test design, it is found that the synergistic effect of various factors has a great effect on the performance of the anti-collapse agent. The effects of various factors on the properties of the synthetic polycarboxylic acid slump retention agent were obtained as follows: acid / ether ratio > complex molecular weight regulator > modified initiator > reaction temperature > reaction time. The optimum reaction conditions were obtained as follows: the reaction temperature was 60 鈩
本文编号：2248850
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