Miniemulsion polymerization of styrene with chain transfer agent as cosurfactant

✍ Scribed by Shouting Wang; Gary W. Poehlein; F. Joseph Schork

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 833 KB
• Volume: 35
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(199703)35:4<595::aid-pola1>3.0.co;2-p

✦ Synopsis

Miniemulsion polymerization

of styrene with the chain transfer agent n-dodecyl mercaptsn (DDM) used as cosurfactant was studied. Droplet size and shelf life for unpolymerized miniemulsions were measured and compared with those of equivalent macroemulsions. The miniemulsion monomer droplets with dodecyl mercaptan as cosurfactant were very stable.

Shelf lives were from 17 h to 3 months. The kinetics of miniemulsion polymerization were studied. Unlike other miniemulsion systems where the cosurfactant does not act as a chain transfer agent, the polymerization rate falls with cosurfactant level because the chain transfer agent enhances radical resorption from the particles. The polymerization rate in all the miniemulsions was lower than that of the corresponding macroemulsions. Polymerized particles were larger than in the corresponding macroemulsions, but molecular weights were lower. Results indicate that DDM can serve as an effective cosurfactant as well as a chain transfer agent. The fact that the molecular weights are lower in the miniemulsion reactions indicates predominant droplet nucleation. c ]9$)7 John Wiley & Sons, Inc.