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Non‐steady‐state model for kinetics of free radical polymerization, 4. Direct thermal initiation
Author(s) -
Yan Deyue,
Lin Jianming,
Yuan Cuiming
Publication year - 1992
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.4990280302
Subject(s) - dispersity , polymerization , monomer , kinetic chain length , kinetics , radical polymerization , chain transfer , molar mass distribution , polymer , thermodynamics , polymer chemistry , bulk polymerization , materials science , thermal , reaction rate constant , chemistry , organic chemistry , physics , classical mechanics
This paper deals with the non‐steady‐state kinetics of direct thermal initiated polymerization. The initiation is assumed to be a bimolecular reaction of the monomer. The relationship between the radical concentration and the monomer conversion is rigorously derived. In further treatment a few very close approximations are introduced based on the fact that the number of monomer molecules reacting in the initiation step is much less than that consumed in the propagation step for a process producing high polymer, and the value of the rate constant for propagation or chain transfer is much lower than that for chain termination. Expressions for various molecular parameters, such as molecular weight distribution, number‐average and weight‐average degrees of polymerization, and dispersity, are given. Several numerical examples are provided.