Synthesis and Application of Ethenyloxy-polyoxyethylene Ether Slump Retaining Typed Polycarboxylate Superplasticizer
Based on molecular structure design theory,a polycarboxylic acid superplasticizer with high slump retai-ning performance was prepared by free radical polymerization with acrylic acid and acrylamide in the Redox system of sodium erythorbate/Na2SO3 and Fe2+,using ethenyloxy polyoxyethylene ether with double bond directly connect-ed with oxygen atom as polymeric monomer.The results showed that the ethenyloxy-polyoxyethylene ether has high-er polymerization activity than conventional polyether monomer due to its C =C double bond directly connected with oxygen atom,and the time of induction period can be shortened by nearly 1/2.The initial and 1 h slump of the prepared concrete can be increased by 16% and 64%,respectively,compared with conventional water reducing agents.However,the initial and 1 h slump expansion were 7%and 22%higher.The FT-IR spectra showed that the amide group and carboxyl group of the functional monomers were successfully grafted on the main chain of polycar-boxylic acid superplasticizer.