Benzoxazine/Triphenylamine-Based Dendrimers Prepared through Facile One-Pot Mannich Condensations

Abstract

A series of thermally polymerizable dendrimers of various generations, equipped with triphenylamine (TPA) and benzoxazine (BZ) groups, is synthesized through facile one-pot Mannich condensations of N¹ ,N¹ -bis(4-aminophenyl)benzene-1,4-diamine (TPA-3NH₂ , as the core group), 4-(bis(4-aminophenyl)amino)phenol (TPA-2NH₂ -OH, as the AB₂ branching group), and CH₂ O in 1,4-dioxane. The ratios of the integrated areas in the ¹ H nuclear magnetic resonance spectra of these dendrimers are consistent with the theoretical numbers of protons, suggesting their successful syntheses. Bathochromic shifts of signals are evident in the UV-vis and photoluminescence spectra upon increasing the generation of the TPA-BZ dendrimers, consistent with an increase in the effective conjugation length. The TPA-BZ dendrimers are able to undergo thermal polymerization and display unique optical physical properties, resulting in thermoset TPA networks after thermal ring-opening polymerization.

Keywords: benzoxazine; dendrimer; thermal curing; triphenylamine.