聚羧酸系减水剂的常温合成及性能

以异丁烯醇聚氧乙烯醚(HPEG)、丙烯酸(AA)、甲基丙烯磺酸钠(SMAS)为单体,通过芬顿试剂引发反应,在常温下制备了三元聚羧酸型减水剂(PC),探讨了不同反应条件对减水剂分散性能的影响,并通过傅里叶红外(FTIR)和凝胶渗透色谱(GPC)等手段对共聚物进行了表征。得到最佳合成条件为:引发剂滴加时间3h,引发剂过氧化氢/硫酸亚铁质量比1.2:1,反应温度30℃,酸醚摩尔比4:1,磺酸盐用量为单体总质量的1.6%,链转移剂用量为总单体质量的1.5% 。当减水剂折固掺量为0.3%时,水泥初始净浆流动度为290 mm,1h后提升到302mm。此常温下合成的减水剂具有良好的分散性和保持性,该方法是一种有应用前景的常温合成方法。

Synthesis and properties of polycarboxylate superplasticizer at room temperature

With Isobutene polyoxyethylene ether (HPEG), acrylic acid (AA), methyl propene sulfonate (SMAS) as raw material, and initiated by Fenton reagent, polycarboxylate superplasticizers were prepared at room temperature. Relationship between different reaction condition and dispersion of polycarboxylic superplasticizer was discussed respectively. The copolymer was analyzed by Fourier transform infrared spectrometer(FTIR) and Gel permeation chromatography(GPC) .The optimal condition of synthesis is obtained as follows:H₂O₂/Fe²⁺as initiator was used in an amount of 2% of the total mass of the monomers and m(H₂O₂):m(FeSO₄)=1.2:1, the titration time of initiator was 3h, the polymerization temperature was 30℃, n(AA):n(HPEG)=4:1, the dosage of sulphonates was 1.6% of the total mass of the monomers, the chain transfer agent was thioglycolic acid and the dosage is 1.5% of the total mass of the monomers. The results showed that the initial fluidity of cement paste could exceed 290 mm and exceed 302mm after 1hours, when the dosage of polycarboxylate water reducer was 0.3% of cement mass, together with 0.29 of water cement ratio. This polycarboxylate superplastic synthesized at room temperature has high dispersity and dispersion retention, which provides a promising room temperature synthesis method.