硅烷改性聚醚制备降黏型聚羧酸减水剂及其性能研究

Preparation and properties of viscosity-reducing polycarboxylate superplasticizer by silane modification of polyether

通过催化3-缩水甘油醚氧基丙基三甲氧基硅烷(KH560)在甲基烯丙基聚氧乙烯醚(HPEG)末端进行开环反应制备出末端硅烷改性聚醚(S-PE),并将其部分替代HPEG与丙烯酸(AA)进行自由基共聚制备出末端硅烷改性聚羧酸减水剂(S-PCE)。对比验证S-PCE和普通减水型聚羧酸减水剂(PCE)在水泥浆体中的吸附量以及对水泥浆体分散性和黏度的影响。结果表明,S-PE替代率为30%时具有更优的分散性,与PCE相比,吸附量最高增大约24%,加快了砂浆的平均流速,使砂浆V型漏斗流出时间缩短约37%,使混凝土倒置坍落度筒排空时间缩短35%,而对混凝土的含气量及抗压强度无明显影响。

Silane-modified polyether(S-PE)was prepared by catalyzing the ring-opening reaction of 3-glycidyl etheroxypropyl trimethoxysilane(KH560)at the end of methylallyl polyoxyethylene ether(HPEG).The terminal silane modified polycarboxylic acid superplasticizer(S-PCE)was prepared by free radical copolymerization with acrylic acid(AA)and partial replacement of HPEG.The selective adsorption mechanism of S-PCE and ordinary water-reducing polycarboxylic acid water-reducing agent(PCE)on the surface of cement particles and the effect of adsorption on the dispersion and viscosity of cement slurry were compared.The results show that when the optimal replacement rate of S-PE is 30%,S-PCE has better dispersibility,and the maximum adsorption capacity of S-PCE is about 24%higher than that of PCE,thus increasing the average flow rate of mortar and shortening the discharge time of mortar in V funnel by about 37%.Compared with PCE,S-PCE can shorten the emptying time of concrete in slump cylinder by 35%,and has no influence on the gas content and compressive strength of concrete.