缓释型聚羧酸保坍剂的合成与性能研究

以常规聚醚单体TPEG、丙烯酸(AA)为主要原料,引入新型不饱和小单体甲基丙烯酰氧乙基琥珀酸单酯(MS),在双氧水(HP)-维生素C(Vc)引发体系下,采用常温自由基溶液聚合反应制备缓释型聚羧酸保坍剂PC-1。研究MS、AA、Vc和巯基丙酸(T1)等用量对PC-1性能的影响,并采用红外光谱对合成的PC-1进行结构表征。结果表明,PC-1具有预期的化学结构,PC-1的最佳制备工艺为:m(TPEG)∶m(AA)∶m(MS)=100∶5∶6,Vc、T1用量分别为大单体质量的0.2%、1.0%。掺PC-1的C30混凝土初始和60、120、180 min坍落度保持性均明显优于同类聚羧酸保坍剂。

Research on the synthesis and performance of a sustain-released polycarboxylate slump retaining agent

Sustain-released polycarboxylate slump retaining agent PC-1 are prepared by free radical solution polymerization at room temperature under the hydrogen peroxide (HP)-vitamin C(Vc) initiation system,while using conventional polyether monomer (TPEG) and acrylic acid(AA) as main raw materials and introducing a new unsaturated small monomer 2-Methacryloyloxyethyl succinate. The effects of the dosage of MS,AA,Vc and T1 on PC-1 performance were discussed. The synthetic polymers are characterized by IR. It shows that the sample of the sustain-released polycarboxylate slump retaining agent has the expected chemical structure. The results show that sustain-released polycarboxylate slump retaining agent had a optimized preparation condition at the mass ratio of TPEG∶AA∶MS=100∶5∶6,Vc and mercaptopropanoic acid was 0.2% and 1% of total mass respectively. The results of C30 concrete test show that slump keeping capacity of PC-1 in initial,60 min,120 min and 180 min are obviously better than those of the same kind of polycarboxylate retaining-agents.