摘   要：以异丁烯醇聚氧乙烯醚（HPEG）、丙烯酸（AA）为主要聚合单体，甲基丙烯酸羟乙酯（HEA）部分取代AA，巯基丙酸（MPA）为链转移剂，通过双氧水（H2O2）-抗坏血酸（Vc）引发，采用一步合成方法，在低温条件下制备了一种缓释型聚羧酸减水剂。研究分析了反应温度、酸醚比、HEA取代量、MPA用量、H2O2与Vc摩尔比、滴加时间等因素对合成减水剂产品性能的影响。利用正交试验，筛选出低温条件下较优的合成工艺：反应温度40℃，n（AA）∶n（HPEG）=4∶1，n(HEA)∶n(HPEG)=4.38:1，MPA用量（按HPEG单体质量分数计，下同）为0.65%，引发剂用量为1.17%，n（H2O2）∶n（Vc）=2.5∶1，滴加时间3h。当减水剂折固掺量为0.22%时，水泥初始净浆流动度达到280mm，0.5h后净浆流动度达到295mm，1h后净浆流动度达到302mm，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，且胶砂减水率达到37.5%。此外，通过傅里叶红外（FTIR）和热重分析（TGA）等手段对共聚物进行了表征。
Abstract: Sustained-release polycarboxylate superplasticizer was prepared in one step at low-temperature by using modified polyether macromer(HPEG), acylic acid(AA) as raw materials, AA partly replaced by hydroethyl methacrylate(HEA), mecraptopropionic acid(MPA) as the chain transfer agent, initiated by hydrogen peroxide(H2O2)-Vitamin C(Vc). The effect of the reaction temperature, the molar ratio of n（AA） to n（HPEG）, the replace amount of HEA, the amount of MPA, the molar ratio of n(H2O2) to n(Vc), and the adding time, etc. on the properties of the production were studied. The orthogonal experimental results indicate that the optimum technology of synthesis are shown as follows: the reaction temperature is 40℃, n（AA）∶n（HPEG）=4∶1, n(HEA)∶n(AA)=4.38∶1, the MPA addition (based on the weight of HPEG, similarly hereinafter) is 0.65%, the weight of initiator is 1.17%, n(H2O2)∶n(Vc)=2.5∶1, and the adding time is 3h. The results show that the initial fluidity of cement paste can exceed 280mm, exceed 295mm after 0.5h and exceed 302mm after 1h when the dosage of polycarboxylate water reducer is 0.22% of cement mass. The polycarboxylate superplastic synthesized has higher dispersity and dispersion retention with the same addition amount than others, and the water reducing rate of mortar reaches 37.5%. In addition, the copolymer is characterized by Fourier transform infrared spectrometer(FTIR) and thermal gravimetric analysis(TGA).