Compartmentalization in Atom Transfer Radical Polymerization (ATRP) in Dispersed Systems

✍ Scribed by Yasuyuki Kagawa; Per B. Zetterlund; Hideto Minami; Masayoshi Okubo

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 154 KB
• Volume: 15
• Category: Article
• ISSN: 1022-1344
• DOI: 10.1002/mats.200600049

✦ Synopsis

Abstract

Summary: Compartmentalization in atom transfer radical polymerization (ATRP) in dispersed systems at low conversion (<10%) has been investigated by means of a modified Smith–Ewart equation focusing on the system n‐butyl acrylate/CuBr/4,4′‐dinonyl‐2,2′‐dipyridyl at 110 °C. Compartmentalization of both propagating radicals and deactivator was accounted for in the simulations. As the particle diameter (d) decreases below 70 nm, the polymerization rate (R~p~) at 10% conversion increases relative to the corresponding bulk system, goes through a maximum at 60 nm, and thereafter decreases dramatically as d decreases further. This behavior is caused by the separate effects of compartmentalization (segregation and confined space effects) on bimolecular termination and deactivation. The very low R~p~ for small particles (d < 30 nm) is due to the pseudo first‐order deactivation rate coefficient being proportional to d^−3^.

Simulated propagating radical concentration ([P•]) as a function of particle diameter (d) at 10% conversion for ATRP of n‐butyl acrylate ([__n__BA]~0~ = 7.1 M, [PBr]~0~ = [CuBr/dNbpy]~0~ = 35.5 mM) in a dispersed system at 110 °C. The dotted line indicates the simulated [P•] in bulk at 10% conversion.

magnified imageSimulated propagating radical concentration ([P•]) as a function of particle diameter (d) at 10% conversion for ATRP of n‐butyl acrylate ([__n__BA]~0~ = 7.1 M, [PBr]~0~ = [CuBr/dNbpy]~0~ = 35.5 mM) in a dispersed system at 110 °C. The dotted line indicates the simulated [P•] in bulk at 10% conversion.