固井水泥浆用两性离子型聚羧酸分散剂的合成及性能评价

Synthesis and Performance Evaluation of Zwitterionic Polycarboxylate Dispersant for Cementing Slurry

现有缩聚物类分散剂因技术和环保问题,其生产和使用受到限制。聚羧酸(PCE)高性能减水剂,绿色环保,分散性能优异,在混凝土工业中广泛使用,但常规PCE应用于固井水泥浆存在强缓凝问题。以甲基烯丙基聚乙二醇醚、丙烯酸和甲基丙烯酰氧乙基三甲基氯化铵为原料,分别合成了常规阴离子型聚羧酸(CPC)和两性离子型聚羧酸(DPC)分散剂,并对其结构进行了表征,同时研究了CPC和DPC对水泥浆流动度、流变性能、稠化时间和抗压强度的影响和作用机理。结果表明:CPC和DPC均有良好的分散性能,但在稠化时间和抗压强度性能上DPC远超CPC。CPC存在很强的缓凝作用,导致稠化时间大幅延长,水泥石早期强度下降。引入季铵阳离子合成的DPC,缓凝作用微弱,对稠化时间影响不大,有利于水泥石早期强度提高。

Due to technical and environmental issues,the production and use of existing polycondensation dispersants are constrained.Polycarboxylate(PCE)superplasticizers are green and environmentally friendly,and have excellent dispersion performance.Although PCE is widely utilized in the concrete field,it causes a significant retarding effect when applied in cementing field.In this work,conventional anionic polycarboxylate(CPC)and zwitterionic polycarboxylate(DPC)dispersants were synthesized by using isobutenol polyethylene glycol ether,acrylic acid and methacryloyloxyethyl trimethyl ammonium chloride as raw materials.Their structures were characterized,and their effects and mechanisms on the fluidity,rheological properties,thickening time and compressive strength of cement slurry were studied.The results indicate that both CPC and DPC have good dispersing properties,but DPC is much better than CPC in terms of thickening time and compressive strength.CPC has a strong retarding effect,which leads to a significant increase in thickening time and a decrease in the early strength of the cement stone.The introduction of quaternary ammonium cation synthesised DPC has a weak retarding effect,which has little effect on the thickening time and is conducive to the improvement of the early strength of the cement stone.