Synthesis of cationic flocculants by the inverse microemulsion copolymerization of acrylamide with 60% 2‐acryloxyethyltrimethyl ammonium chloride in the monomer feed. I. Initiation by ammonium persulfate/sodium disulfite redox system

Abstract

Acrylamide/2-acryloxyethyltrimethyl ammonium chloride copolymers in inverse microemulsion, with a cationic charge density of 60% and a concentration of active matter of 30 wt %, of interest as flocculants have been obtained by inverse microemulsion copolymerization. Interesting inverse microemulsion formulations from both industrial and economical standpoints were selected from pseudoternary phase diagrams. These formulations were polymerized by semicontinuous free radical copolymerization in inverse microemulsion using sodium disulfite and ammonium persulfate as initiators. Influence of initiators and initiator addition conditions (specific flow rate and concentration) on semicontinuous polymerization and final product properties as flocculants have been studied. A strong difference in copolymer solution viscosity has been found when an aqueous solution of sodium disulfite is used as initiator instead of sodium disulfite/ammonium persulfate couple redox, specially for low sodium disulfite solution feeding flow.

Synthesis of cationic flocculants by the inverse microemulsion copolymerization of acrylamide with 60% 2‐acryloxyethyltrimethyl ammonium chloride in the monomer feed. II. Influence of the formulation composition, hydrophilic‐lipophilic balance, starting polymerization temperature, and reaction time

“…All stable microemulsions published by Escudero et al 2 had bicontinuous microstructures rather than globular microstructures. This microstructure did not remain throughout the polymerization process but was modified during polymerization, producing a final globular microemulsion.…”

“…The relationship between the HLB and formulation composition before polymerization has been discussed in an earlier work. 2 Now we discuss this relationship during polymerization.…”

“…The results and methods have been presented before. 2 As the conclusion of that study, the following formulation was selected: 60% APh, 30% oil phase, and 10% surfactant blend (HLB ¼ 9.5). This formulation gives a cationic copolymer concentration of 30% with 60% cationic monomer.…”

“…In an earlier work, 2 we studied polymerization initiation with ammonium persulfate and sodium disulfite (DS) as the initiators. In that work, we proved that DS could initiate AM/ADQUAT copolymerization itself, contrary to what was expected.…”

Effect of polymerization method on structure and properties of cationic polyacrylamide

“…Acrylamide‐based cationic polymers are widely used in a variety of industrial applications in the treatment of sewage, the clarification of industrial wastewater, solids/liquid separation, and in papermaking as strength additives, flocculation3, drainage and retention aids, corrosion inhibition4 etc. Acrylamide(AM) and 2‐(methacryloyloxy)ethyltrimethylammonium chloride (MADQUAT) copolymers (p(AM‐MADQUAT)) is one of cationic acrylamide‐based polymers containing quaternary amine group, and it is synthesized by solution polymerization conventionally, wherein resultant polymer has a less uniform monomer distribution.…”