Determination of Propagation Rate Coefficient of Acrylates by Pulsed-Laser Polymerization in the Presence of Intramolecular Chain Transfer to Polymer

✍ Scribed by Anatoly N. Nikitin; Patrice Castignolles; Bernadette Charleux; Jean-Pierre Vairon

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 135 KB
• Volume: 24
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.200350025

✦ Synopsis

Abstract

Unusual difficulties are faced in the determination of propagation rate coefficients (k~p~) of alkyl acrylates by pulsed‐laser polymerization (PLP). When the backbiting is the predominant chain transfer event, the apparent k~p~ of acrylates determined in PLP experiments for different frequencies should range between k~p~ (propagation rate coefficient of the secondary radicals) at high frequency and k at low frequency. The k value could be expressed from kinetic parameters: $k_{\rm p}^{{\rm av}} = k_{\rm p} - {{k_{\rm p} - k_{{\rm p}2} } \over {1 + {{k_{{\rm p}2} [{\rm M}]} \over {k_{{\rm fp}} }}}}$, where k~fp~ is the backbiting rate coefficient, k~p2~ is the propagation rate coefficient of mid‐chain radicals, and [M] is the monomer concentration.

Apparent propagation rate coefficients determined for different frequencies by simulating the PLP of n‐butyl acrylate at 20 °C. Horizontal full lines show the values of k~p~ and k.

magnified imageApparent propagation rate coefficients determined for different frequencies by simulating the PLP of n‐butyl acrylate at 20 °C. Horizontal full lines show the values of k~p~ and k.