Preparation and properties of super early strength polycarboxylic acid superplasticizer
KANG Jingxin
CHEN Xiamin
LI Fang
Abstract：Modified polyether CA-HPEG with hydroxyl end grafted carboxyl group was prepared by alcoholysis of cyclic diacid anhydride,and then modified polyether LPEG was prepared by amidation reaction with amino siloxane.The modified polyether LPEG was introduced into copolymerization reaction with amide monomer to prepare ultra-early strong polyether car-boxylic acid water reducing agent SPE with long side chain and short main chain.Optimize the process of SPE and explore its effects on the flowability of cement paste,early strength of mortar,and performance of concrete mixtures,the structures of modified polyether LPEG and SPE were characterized by infrared spectroscopy,and the cement hydration products of SPE was analyzed by X-ray diffractometer.The test results show that the optimum esterification conditions of modified polyether CA-HPEG are as fol-lows:molar ratio of cyclic dianhydride to HPEG5000 is 2∶1,reaction time is 2h and reaction temperature is 60 ℃.The optimum synthesis parameters of SPE are:n(LPEG)∶n(HPEG5000)=2∶3,n(AA)∶n(AM)=3∶1,n(AA+AM)∶n(LPEG+HPEG5000)=4.5∶1,the amount of initiator APS was 0.45％of the mass of polyether monomer,the amount of chain transfer agent was 0.25％of the mass of polyether monomer,the reaction temperature was normal temperature,and the drop time is 3h,SPE can shorten the initial and final setting time of concrete,and the early compressive strength increases obviously.
Keywords：cyclic dianhydride alkolysisamino siloxanesuper early strength polycarboxylic acid water reducerfinal setting time
Publication Date：2024-10-25
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 47-51 )