Influences of MAA on the porous morphology of P(St–MAA) latex particles produced by batch soap-free emulsion polymerization followed by stepwise alkali/acid post-treatment

• Published in: Journal of colloid and interface science Vol. 349; no. 1; pp. 122 - 126
• Main Authors: Deng, Wei, Li, Ronglong, Zhang, Mengjun, Gong, Lixiang, Kan, Chengyou
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.09.2010; Elsevier
• Subjects: Acids - chemistry; Alkalies - chemistry; Chemistry; Colloidal state and disperse state; Copolymerization; Emulsions; Emulsions - chemical synthesis; Emulsions - chemistry; Exact sciences and technology; General and physical chemistry; Latex; Methacrylates - chemical synthesis; Methacrylates - chemistry; Methacrylic acid; Microspheres; Morphology; Particle morphology; Particle Size; Porosity; Porous materials; Porous structure; Scanning electron microscopy; Soap-free emulsion polymerization; Stepwise alkali/acid post-treatment; Styrene - chemical synthesis; Styrene - chemistry; Styrenes; Transmission electron microscopy; Porous structure; Methacrylic acid; Soap-free emulsion polymerization; Stepwise alkali/acid post-treatment; Particle morphology; Scanning electron microscopy; Hydrocarbon; Emulsion copolymerization; Rough surface; Soap; Porous material; Latex; Particle; Pore size; Transmission electron microscopy; Emulsion polymerization; Morphology; Styrene; Benzenic compound; Structure
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2010.05.033

The amount of MAA intensively influenced the morphology of P(St–MAA) latex particles, and the particles showed different morphology after alkali and stepwise alkali/acid post-treatment. Soap-free P(St–MAA) latex particles with variable styrene (St)/methacrylic acid (MAA) ratio were synthesized by batch emulsion copolymerization at 70 °C for 7 h, and the particles with porous structure were obtained after stepwise alkali/acid post-treatment. The effects of MAA amount on the particle morphologies after the alkali and the stepwise alkali/acid post-treatments were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Results indicated that the alkali-treated latex particles showed anomalous structure with rough surface, and no hollow was clearly identified inside them. When these alkali-treated particles were further treated with acid solution, the particle surface became much smoother, and porous morphology appeared. It was found that when the MAA amount was less than or equal to 4 mol%, no obvious morphological variation was observed; while the latex particles showed clearly porous structure as the MAA amount increased to 6 mol%; with the further increase of MAA amount to 8 mol%, the pore size decreased distinctly.