Special Features of Network Build-Up in Curing of Polyepoxides Based on N,N-Diglycidylaniline Derivatives
The curing of N-N-diglycidylaniline (DGA) and N,N,N′,N′-tetraglycidyl-diaminodiphenylmethane with polyamines differs from that of diglycidyl ether of hisphenol-A by a high tendency to cyclization and by interdependence of reactivities of the glycidyl groups bound to the same nitrogen atom. Cyclization is characterized by formation of small cycles by intramolecular epoxy-amine addition or etherification. The reaction of the monoadduct of DGA and a secondary amine bearing another epoxy group with another secondary amine molecule is considerably faster than that of DGA with the same secondary amine. This feature is explained by intramolecular catalysis of the addition by the OH group in the monoadduct. The interplay of the substitution effects in the amine group and in DGA as reflected in gelation is complex, however. The development of a statistical branching theory taking these features into account is outlined.
KeywordsSecondary Amine Epoxy Group Diglycidyl Ether Substitution Effect Small Cycle
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