RAFT法制备嵌段型聚羧酸减水剂及其水化性能

Preparation of Block Polycarboxylic by RAFT and Its Hydration Properties

以聚烷氧烯基长链不饱和单体和丙烯酸为单体,S,S′-二(α,α′-甲基-α″-乙酸)三硫代碳酸酯(TRIT)为链转移剂,偶氮二异丁腈(AIBN)为引发剂,通过可逆加成-断裂链转移聚合(RAFT)合成了系列不同单体比例的嵌段型聚羧酸减水剂,采用FT-IR、SEM和TG对减水剂的结构和性能进行表征。砂浆流动度测试结果表明:单体比例为1/6时,样品减水性能最优,钙矾石结晶生长良好且呈现针状,水泥水化速度相对较快。

A serials of block polycarboxylic were synthesized by reversible addition-fragmentation chain transfer polymerization(RAFT), using polyalkoxy alkylene group macromonomers and acrylic acid as monomers, S,S ′-bis(α,α′-dimethyl-α″-acctic acid) trithiocarbionate(TRIT) as chain transfer agent, azodiisobutyronitrile as initiator. The structure and properties were characterized by FT-IR, SEM and TG. The results of mortar fluidity test showed that the sample prepared by 1/6 monomer ratio had the best water reducing performance. The needle shaped ettringite grew well, and the cement hydration rate was relatively fast.