Synthesis of low-molecular weight itaconic acid polymers as nanoclay dispersants and dispersion stabilizers ( vol 265, pg 125614, 2023)

Itaconic oligomers with an average molecular weight of Mn = 1500–2200 g/mol and different end-groups were prepared by 2,2′-azobis(2-methyl-propionamidine) dihydrochloride (V-50) – induced radical polymerization of itaconic acid (IA) in aqueous solution at 65 °C for 24 h. Mercaptoethanol, thioglycerol, and sodium hypophosphite were used as chain transfer agents (CTA) with the molar ratio ranging from 30:3:1 to 30:3:4 of IA, V50, and CTA, respectively. The structure of the oligomers was confirmed by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). The excellent dispersing efficiency of the oligomers at very low concentrations for Laponite® sols was proved by oscillatory rheology and small-angle X-ray scattering (SAXS) measurements.