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A mechanistic kinetic model for the initiated anionic polymerization ofϵ‐caprolactam
Author(s) -
Cimini R. A.,
Sundberg D. C.
Publication year - 1986
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760260807
Subject(s) - caprolactam , polymerization , kinetics , reaction rate constant , nylon 6 , reaction rate , reaction mechanism , polymer chemistry , kinetic energy , polymer , materials science , degradation (telecommunications) , anionic addition polymerization , catalysis , elementary reaction , chemistry , organic chemistry , computer science , physics , telecommunications , quantum mechanics
The preparation of Nylon‐6 via the initiated anionic polymerization of EE‐caprolactam is characterized by rapid reaction rates displaying marked auto‐acceleration. A mechanistic approach has been taken to analyze the kinetics of this system and has resulted in the postulation that the auto‐acceleration is directly linked to a polymer chain degradation reaction. This reaction is significant even in the early stages of the polymerization and in many cases becomes the dominant mechanism for the production of reactive end groups, thereby controlling the overall reaction rate. A kinetic model is presented which is capable of differentiating between polymerizations carried out with different levels and ratios of catalyst and initiator, and contains but two rate constants—one for the propagation reaction and one for the degradation reaction. Predictions of the model are compared to experimental rate data derived from using both mono‐and difunctional initiators and close agreement is found.