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Effect of reaction medium on ionic lactam polymerization
Author(s) -
Šebenda J.
Publication year - 1990
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19900320110
Subject(s) - cationic polymerization , polymerization , ionic polymerization , chain growth polymerization , polymer chemistry , kinetic chain length , chemistry , monomer , precipitation polymerization , chain transfer , bulk polymerization , photochemistry , solution polymerization , anionic addition polymerization , living polymerization , polymer , materials science , organic chemistry , radical polymerization
Abstract Ring‐size and substitution greatly affect the permittivity and donor‐acceptor properties of lactams and their derivatives as well as of the corresponding polymers. Permittivity changes occurring during bulk polymerization affect dissociation equilibria and the very high increase in permittivity during polymerization is responsible for the autoacceleration observed in the anionic polymerization of the seven‐membered lactam. In diluted solution, pronounced effects of the nature of solvent or additive have been observed in anionic polymerization of substituted four‐membered lactams. Whereas the initial rate of polymerization is independent of the monomer concentration, the apparent order in the monomer increases and the rate of polymerization in most solvents decreases during polymerization, except in solvents of very low polarity. Changes of permittivity and conductivity during and after polymerization indicate, that changes in the solvation and rearrangement of the growth center are responsible for its varying activity. These processes increase the reactivity during ageing of the living system. Similarly to other heterocyclic monomers, the cationic polymerization of N‐acyllactams is rather insensitive to the permittivity of the reaction medium.