P(AA–SA) latex particle synthesis via inverse miniemulsion polymerization– nucleation mechanism and its application in pH buffering

• Published in: Journal of colloid and interface science Vol. 330; no. 1; pp. 170 - 174
• Main Authors: Luo, Ying-Da, Dai, Chi-An, Chiu, Wen-Yen
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.02.2009; Elsevier
• Subjects: Chemistry; Colloidal state and disperse state; Emulsions. Microemulsions. Foams; Exact sciences and technology; General and physical chemistry; Micelles. Thin films; Miniemulsion polymerization; Particle nucleation; pH buffering; Surface physical chemistry; Particle nucleation; Miniemulsion polymerization; pH buffering; Nucleation; Acrylic acid; Micelle; Surfactant; Mechanism; Sodium hydroxide; Particle; Micellar critical concentration; Emulsion; Synthesis; pH; Inverse; Monomer; Deprotonation; Stability; Polymerization; Crosslinking; Droplet; Latex; Sodium; Osmotic pressure; Physicochemical properties
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2008.10.036

In this work, poly(acrylic acid- co-sodium acrylate) P(AA–SA) latex particles were prepared by inverse miniemulsion polymerization and used as a pH buffering agent for application. The polymerization was quickly initiated by a redox initiator (ammonium persulfate/sodium metabisulfite) at 0–5 °C. Thus the possibility of monomer dissolving in a solvent was reduced, which enhanced the degree of droplet nucleation. The effects of costabilizer and the ratio of SA/(AA + SA) in functional latex particles on the nucleation mechanism and emulsion stability were investigated. The apparent p K a values of the synthesized P(AA–SA) latex particles were determined by titration experiments. Their properties on pH buffering were also studied, including the pH temporal response and pH buffering ability. The results showed that sodium hydroxide, which was introduced as the costabilizer to enhance the osmotic pressure and to increase the deprotonation of acrylic acid, was effective in guaranteeing droplet nucleation predominantly. Meanwhile, the surfactant concentration was controlled to be less than its critical micelle concentration (CMC) value to avoid micellar nucleation. Furthermore, the P(AA–SA) latex particles thus synthesized were found to be an excellent material for pH buffering. The pH temporal response was very rapid and related to the crosslinking degree of the latex particles. The terminal range of pH buffering for latex particles was controllable by the ratio of SA/(AA + SA). In this work, P(AA–SA) latex particles were synthesized via inverse miniemulsion polymerization and found to be an excellent material for pH buffering.