Structure Formation Process of Copolymerization of Methyl Allyl Polyethylene Glycol with Acrylic Acid
1. College of Material Science and Engineering, Beijing University of Technology, Beijing 100124, China;
2. Institute of Technical Information for Building Materials Industry, Beijing 100024, China
Abstract： In order to study the formation process of molecular structure of Polycarboxylate Superplasticizer (PCE) during copolymerization, the rule and range of deviation of acid/ether ratio from designed acid/ether ratio in each time period, and the influence of different initiator systems on the formation process of molecular structure of PCE, PCE was synthesized by using methyl allyl polyethylene glycol (MAPEG) and acrylic acid (AA) as co-polymerization monomers, initiated by ammonium persulfate (APS) and redox initiation system (H2O2-Vc) according to double-titration addition process. The content of monomers and formed polymers in the reaction system were determined by gel permeation chromatography (GPC) and high performance liquid chromatography (HPLC). The molecular weight and dispersity, mean square radius of rotation, compositions of monomers (acid/ether ratio) and monomer conversion were obtained at different reaction stages. The characteristics of polymer formation during PCE copolymerization in APS and H2O2-Vc systems were analyzed and summarized. It was found that in APS system, a polymer with a longer main chain was formed at 90 minutes, and in H2O2-Vc system, a polymer with a shorter main chain was formed at 60 minutes. The acid/ether ratio of the polymer formed in the two initiator systems deviated from the initial design value in various copolymerization period. The acid/ether ratio of the polymer formed in the initial reaction (0-120 minutes) was less than the design value, and the acid/ether ratio of the polymer formed in the middle reaction (120-240 minutes) was higher than the design value. At the end of monomer dropping, the maximum deviation value was more than 160% of the designed acid/ether ratio. The acid/ether ratio of the polymer formed at the late stage (240-360 minutes) depends on the initiation system and process control.
WANG Ziming1,ZHAO Meili1,ZHANG Yang2. Structure Formation Process of Copolymerization of Methyl Allyl Polyethylene Glycol with Acrylic Acid[J]. 化学反应工程与工艺, 2019, 35(3): 234-241.
