Low Conversion 4-Acetoxystyrene Free-Radical Polymerization Kinetics Determined by Pulsed-Laser and Thermal Polymerization

✍ Scribed by Ning Li; Andrew S. Cho; Linda J. Broadbelt; Robin A. Hutchinson

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 250 KB
• Volume: 207
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200600232

✦ Synopsis

Abstract

Summary: The free‐radical polymerization kinetics of 4‐acetoxystyrene (4‐AcOS) is studied over a wide temperature range. Pulsed‐laser polymerization, in combination with dual detector size‐exclusion chromatography, is used to measure k~p~, the propagation rate coefficient, between 20 and 110 °C. Values are roughly 50% higher than those of styrene, while the activation energy of 28.7 kJ · mol^−1^ is lower than that of styrene by 3–4 kJ · mol^−1^. With known k~p~, conversion and molecular weight data from 4‐AcOS thermal polymerizations conducted at 100, 140, and 170 °C are used to estimate termination and thermal initiation kinetics. The behavior is similar to that previously observed for styrene, with an activation energy of 90.4 kJ · mol^−1^ estimated for the third‐order thermal initiation mechanism.

Joint confidence (95%) ellipsoids for the frequency factor A and the activation energy E~a~ from non‐linear fitting of k~p~ data for 4‐AcOS (black) and styrene (grey).

magnified imageJoint confidence (95%) ellipsoids for the frequency factor A and the activation energy E~a~ from non‐linear fitting of k~p~ data for 4‐AcOS (black) and styrene (grey).