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Curing mechanism of epoxides by imidazoles
Author(s) -
Jíšová Václava
Publication year - 1987
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1987.070340718
Subject(s) - curing (chemistry) , materials science , mechanism (biology) , polymer science , composite material , polymer chemistry , physics , quantum mechanics
The courses of the reactions of the epoxides with the various derivatives of imidazole in the concentration range 0.5–25 epox. weight eq./mol imidazole and in the temperature range 80–155°C were studied. All imidazoles from adducts with epoxides very quickly, namely the 1‐substituted imidazole 1 : 1 adducts, in case of the 1,3‐unsubstituted imidazoles the reaction continues to the 1 : 2 adducts. The polymerization effectiveness of the imidazoles falls in order 2‐ethyl‐4‐methylimidazole (EMI) > 1‐ n ‐butylimidazole (BI) > 2‐phenylimidazole (PI) > imidazole (I) ≫ 1‐vinylimidazole (VI) > benzimidazole (BZI). The effect of temperature, epoxide, and imidazole concentrations on the overall curing rate and the limiting conversion were investigated. In the concentration and temperature range studied the overall curing rate is directly proportional to the imidazole and epoxide concentrations and follows the Arrhenius ratio with similar values of the overall activation energy E a = 70 to 79 kJ/mol for all active tested imidazoles in the studied concentration and temperature range.