Inverse suspension polymerization of sodium acrylate: Synthesis and characterization

摘要

Crosslinked Poly(acrylic acid) was synthesized by inverse suspension polymerization. This process was investigated to determine the influence of different parameters like temperature, stirring speed, solution pH, and crosslinker concentration and to obtain the best control of the kinetics. An aqueous phase containing partially neutralized acrylic acid, crosslinking agent, and initiator agent was dispersed in an organic phase and stabilized by a surfactant. The inverse suspension was carried out in heptane as the organic phase with a different ratio of neutralization of the monomer, different crosslinker concentrations, and several stirring speeds. The polymerization was initiated by potassium persulfate (K2S2O8) with N-N'-methyleneloisacrylamide (MBA,) as the crosslinker and sorbitan monooleate as the surfactant. The influence of several parameters on the head size and the swelling capacity was investigated. Particle diameters ranged from 10 to 130 mu m The kinetic results obtained by differential scanning calorimetry showed that conversion and polymerization rates are a function of the solution pH, and they fell when the concentration of the crosslinking agent was higher than 7.5% in the mass of MBA(C). (C) 2000 John Wiley & Sons, Inc. [References: 30]