Modeling of termination in intermediate and high conversion free radical polymerizations

✍ Scribed by Michael Buback; Brigitta Huckestein; Gregory T. Russell

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 883 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950212

✦ Synopsis

Abstract

A simple means of modeling termination in free radical polymerizations of a large number of monomers over a wide variety of intermediate and high conversion conditions is presented. It is shown that monomers can be divided into two classes according to the qualitative variation of their termination rate coefficient (k~t~) with conversion (U). It is then suggested that it is profitable to represent k~t~ data as k~t~/[k~p~·(1 − U)]. Doing this reveals that over a wide range of temperatures and of intermediate and high conversions, seemingly complex variations of k~t~ with U can be described by a single parameter (C~RD~), the value of which varies from monomer to monomer. Proceeding from the idea that the process of reaction‐diffusion is the rate determining mechanism of termination, two easily implementable models for a priori prediction of C~RD~ are developed in parallel from already existing ideas. One of these models is shown to predict with remarkable accuracy a large variety of experimental C~RD~ data. Slight modification of these predictions makes this model even more accurate, and therefore gives it great potential for modeling purposes.