Polymerization Behavior by the Addition of Alcohols

Analogously to water, alcohols (used in the form of polyols) also cause a chain-transfer reaction during the cationic polymerization of epoxides. Polyols (polyvalent alcohols with an average molecular weight from several hundred to several thousand grams/mole) are often utihzed in technical formulations. These serve to reduce the network density of the polymerized epoxide and therefore make the material less brittle. At the same time the reactivity also is influenced and the susceptibiHty of the polymerization rate and polymer properties to the influence of air humidity is reduced. This is important, as the influence of air humidity is difficult to reproduce in technical appHcations. 

4-diol-based polyether polytetrahydrofuran has practically no influence on the rate of polymerization only the conversion is increased. Similarly to the investigations into the influence of air humidity, the corresponding ones into polymerization kinetics of the epoxide layers on gold substrates were carried out with realtime IR spectroscopy. 

2-diol-based polyethers could not be determined from the investigations which were carried out. 

Increasing the onset temperature for a reaction without increasing the temperature for the reaction maximum, by using small amounts of crown ether instead as stabilizer of the usual tertiary amines, allows the stabilization of the 

TEM examination by H. van Eys-Schafer and molecular modehng by B. Schneider are gratefully acknowledged. 

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