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Kinetics of polymerization by activated monomer mechanism
Author(s) -
Biedron Tadeusz,
Szymanski Ryszard,
Kubisa Przemyslaw,
Penczek Stanislaw
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.19900320114
Subject(s) - chemistry , monomer , polymerization , protonation , reaction rate constant , polymer chemistry , epichlorohydrin , ring opening polymerization , kinetics , solvent , organic chemistry , polymer , ion , physics , quantum mechanics
Polymerization of cyclic ethers by activated monomer mechanism involves consecutive additions of protonated monomer molecules to the growing macromolecules fitted with hydroxyl groups at their ends. For oxirane itself and symmetrically substituted oxiranes there is only one kind of hydroxyl groups and one, unique way of ring‐opening. Unsymmetrically substituted oxiranes provide however two sites of attack and two different hydroxyls, resulting from these ring‐openings. Kinetics of polymerization of epichlorohydrin (chloromethyloxirane) has been studied and all four rate constants determined, namely rate constants of the primary and secondary alcoholate chain ends with a protonated monomer, opening in result of the attack on substituted or unsubstituted carbon atom. These rate constants are (in mol −1 ·1·s −1 at 25°C, in CH 2 Cl 2 solvent): k 11 = 0.055, k 12 = = 0.41, k 22 = 0.135, and k 21 = 0.0011 (e.g. k 12 is the rate of reaction of the primary alcohol producing the secondary alcohol). Thus, polymerization proceeds almost exclusively on the secondary alcoholate groups, reproducing themselves (k 22 ).