Title: Study on the Structural Characteristics and Copolymerization Activity of Polyether Macromonomers for Polycarboxylate Superplasticizer

Author(s): Zhao Meili, Zhang Lin, Liu Xiao, Wang Ziming

Publication: Symposium Paper

Volume: 354

Issue:

Appears on pages(s): 113-124

Keywords: copolymerization activity; free radical activity; monomer activity; polyether macromonomer; structural characteristics

DOI: 10.14359/51736066

Date: 7/1/2022

Abstract:
Polyether macromonomers, used for synthesizing polycarboxylate superplastizers (PCE), have been continuously innovated and developed into a series of products possessing different structures and molecular weights with the continuous application expansion of PCE. In this paper, the development process of polyether macromonomers was briefly reviewed, then in order to understand the copolymerization reactivity of commonly used polyether macromonomers (APEG, MAPEG, IPEG, and EVPEG), the structural characteristics, and the electron effect of polyether macromonomers were analyzed. The copolymerization activity of polyether macromonomers was further confirmed by monitoring the conversion rate and composition in copolymers in the copolymerization process. The results show that the electron cloud distribution of polymerizable double bonds in polyether macromonomers is evidently affected by their different end groups. In free-radical copolymerization, the free radical activity of polyether macromonomer, instead of its reactivity ratio, determines the chain growth rate and monomer copolymerization activity. In addition, EVPEG-3000 manifested the highest conversion rate and the highest content in the copolymer, compared with APEG-1200, MAPEG-2400, and IPEG-2400 when copolymerized with acrylic acid (AA) via aqueous free radical copolymerization (acid/ether ratio was 3.75). From high to low, the copolymerization activity of polyether macromonomers is in the order of EVPEG (VPEG), IPEG, MAPEG, and APEG.