Construction and application of surface-active monomers in emulsion polymerization for the synthesis of block polycarboxylate dispersants

• A reactive molecule containing a double bond was synthesized via CCTP. • The introduction of the benzene ring effectively enhances the adsorption capacity of the dispersant on the coal surface. • This method avoids introducing chain transfer agents into the molecular structure, making it environmentally friendly. In the present study, a reactive polymer macromolecule was synthesized by catalytic chain transfer polymerization (CCTP) using poly (ethylene glycol) monomethyl ether methacrylate and methacrylic acid, which has a reactive double bond that continues to participate in free radical polymerization reactions. Afterward, the macromolecule was used as a surface-active monomer and emulsion polymerized with benzyl methacrylate to successfully synthesize a block-type polycarboxylic acid molecule, which was used as a dispersant in the coal water slurry. The hydrophobic components of the dispersant, consisting of its main chain and benzene ring, demonstrate adsorption affinity toward coal surfaces, while its hydrophilic group such as carboxylic acid moiety and polyether branched chains − effectively enhance surface wettability through hydration interactions. The structures of the polymers were characterized by IR and 1 H NMR; the molecular weights and conversion rates of the products were discussed by GPC to explore the optimal synthesis conditions; and the slurry formation properties of dispersants with different monomer ratios were also discussed to optimize the synthesis ratio of dispersants; In addition, the adsorption behavior of the dispersant was also investigated by TOC and XPS, which proved that the introduction of benzene ring improved the adsorption capacity of the dispersant on the coal surface to a certain extent, and also proved that the addition of the dispersant effectively improved the content of the hydrophilic/hydrophobic groups on the surface of the coal, and improved the hydrophilicity of the coal. SEM tests also showed very visually how well the dispersant dispersed the coal.