Scale Inhibitor and Dispersant Based on Poly(Acrylic Acid) Obtained by Redox-Initiated Polymerization

GUTIERREZ, C.G.; CÁCERES, G.; MINARI, R.J.; VEGA, J.R.; GUGLIOTTA, L.M.

MACROMOLECULAR REACTION ENGINEERING

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2019 vol. 19 p. 1 - 8

1862-832X

Low molar mass poly(acrylic acid) (PAA) is generally obtained by free radical polymerization of acrylic acid (AA) in aqueous solution, using thermal initiators and some chain transfer agent. However, under such conditions it is rather difficult to efficiently produce molar masses as low as those required for obtaining an effective dispersant. In this work, the semibatch polymerization of AA at 45 °C is considered, using potassium persulfate (KPS) and sodium metabisulfite (KPS/NaMBS), or alternatively KPS andsodium hypophosphite (KPS/NaHP) as redox initiators to produce PAA ofcontrolled low molar masses. These initiation systems allow the productionof PAA with Mn as low as 2.0 kDa, relatively narrow molar mass distribution(1.5 < Mw/Mn < 3.0), and low branching degree. Most of the investigatedpolymerizations reach almost complete conversions (>95%); and it is verifiedthat both reductants, NaMBS and NaHP, also behave as chain transferagents. Finally, the investigated process with redox couples allowed the productionof PAA with acceptable dispersant and antiscaling properties.