SP–PLP–EPR Investigations into the Chain-Length-Dependent Termination of Methyl Methacrylate Bulk Polymerization

✍ Scribed by Johannes Barth; Michael Buback

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 293 KB
• Volume: 30
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.200900335

✦ Synopsis

Abstract

Termination kinetics of methyl methacrylate (MMA) bulk polymerization has been studied via the single pulsed laser polymerization–electron paramagnetic resonance method. MMA‐d~8~ has been investigated to enhance the signal‐to‐noise quality of microsecond time‐resolved measurement of radical concentration. Chain‐length‐dependent termination rate coefficients of radicals of identical size, k, are reported for 5–70 °C and up to i = 100. k decreases according to the power‐law expression $k_{\rm t}^{i,i} = k_{\rm t}^{{\rm 1,1}} \cdot i^{ - \alpha }$. At 5 °C, k~t~ for two MMA radicals of chain‐length unity is k = (5.8 ± 1.3) · 10^8^ L · mol^−1^ · s^−1^. The associated activation energy and power‐law exponent are: E~A~(k) ≈ 9 ± 2 kJ · mol^−1^ and α ≈ 0.63 ± 0.15, respectively.

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