Effect of hydrophobic chain length on the properties of polycarboxylate polymeric surfactants

In this work, a series of polycarboxylate polymeric surfactants were designed and synthesized from acrylate monomers with different alkyl chain lengths (alkyl chain lengths of 1, 4, 6, 12, 18), epoxy succinic acid (ESA), acrylic acid (AA) and 2-acrylamide-2-methylpropane sulfonic acid (AMPS). Their structures were confirmed by FT-IR, 1H NMR and GPC. A series of surfactant parameters, including critical micelle concentration (CMC), minimum surface tension, surface tension reduction at critical micelle concentration (Πcmc), surface tension reduction efficiency (pC20), etc, were obtained by surface activity test. The results showed that with the increase of the alkyl chain length of acrylate, surface tension and CMC of polycarboxylate polymeric surfactants gradually decreased. When the alkyl chain length of acrylate monomer was 12, the surface tension of polycarboxylate polymeric surfactants was the lowest, which was 32.6 mN/m. The results of TG, DLS and TEM showed that with the increased of the alkyl chain length of the acrylate, the micellar size of polycarboxylate polymeric surfactants decreased regularly. Meanwhile, the foaming, wetting and emulsifying properties of polycarboxylate polymeric surfactants were positively correlated with the alkyl chain length of the acrylate. The dispersing ability of polycarboxylate polymeric surfactants for calcium carbonate was 101.5 mg/g, which can dispersed Fe2O3 fouling to less than 1 μm under the condition of 0.6 g/L.