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目前聚羧酸减水剂的合成工艺主要以加热为主,低温合成工艺报道较少。本文为了解决这一问题,以异戊烯醇聚氧乙烯醚(TPEG)、丙烯酸(AA)为主要聚合单体,研究分析反应温度、保温时间、A/B液滴加时间、酸醚比、引发剂过硫酸铵用量(APS)等因素对合成减水剂产品性能的影响。并利用正交试验,筛选出常温条件下较优的合成工艺:酸醚比n(AA)∶n(TPEG)=3.5∶1,引发剂过硫酸铵用量(按TPEG单体质量分数计)为0.5%,反应温度30℃,A液滴加2.25h,B液滴加3.5h,保温时间1.5h。合成减水剂产品在水灰比0.29,掺量0.25%的条件下,水泥净浆初始流动度达到240mm,1h后净浆流动度损失5mm,相同掺量下与其他减水剂产品相比具有更好的分散性和分散保持性。
At present, polycarboxylate superplasticizer synthesis mainly heating, low temperature synthesis process reported less. In order to solve this problem, the main polymerization monomers of isoprenol polyoxyethylene ether (TPEG) and acrylic acid (AA) were studied. The effects of reaction temperature, holding time, A / B droplet addition time, Effect of initiator ammonium persulfate content (APS) and other factors on performance of synthetic water reducer products. Through the orthogonal test, the optimum synthetic process was screened at room temperature: the ratio of acid ether to n (AA): n (TPEG) = 3.5:1, the amount of ammonium persulfate used as initiator (based on TPEG monomer) 0.5%, reaction temperature 30 ℃, A drop plus 2.25h, B drop plus 3.5h, holding time 1.5h. Under the condition of the water-cement ratio of 0.29 and the content of 0.25%, the initial flowability of the synthetic cement paste reaches 240mm and the fluidity loss of the cement paste after 1h is 5mm. Compared with other water reducer products, Better dispersion and decentralized retention.