Automatic, simultaneous control of polymer composition and molecular weight during free radical copolymer synthesis

Publication date: Available online 21 December 2017
Source:Polymer
Author(s): Terry McAfee, Rick D. Montgomery, Thomas Zekoski, Aide Wu, Wayne F. Reed
Fully automatic, simultaneous control of polymer composition and molecular weight trajectories during free radical copolymer synthesis was achieved by coupling the continuous ACOMP data stream into a feedback controller which operated pumps for reactor feed of comonomers. The controller operates without recourse to a detailed kinetic model or reactivity ratios. Rather, it uses the fact that instantaneous copolymer chain composition is related to the instantaneous rate of consumption of comonomers, and the rate for each of these is described by rates α1 and α2 for comonomers 1 and 2, respectively. The instantaneous weight average molecular weight Mw,inst is proportional to total comonomer concentration via a constant p. Hence, target trajectories for composition and Mw can be independently prescribed and followed. Since α1, α2 and p are directly measurable from the ACOMP data stream, their values can be constantly updated by the automatic controller during the reaction process to insure the target trajectories are followed.

Graphical abstract

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