Synthesis and characterization of pyrrole-based benzoxazine monomers and polymers

Pyrrole and benzoxazine chemistries were merged successfully to prepare pyrrole-containing curable benzoxazine monomers for the first time. For this purpose, initially, a phenolic group containing pyrrole was synthesized by using the Clauson-Kaas route. The obtained phenolic was then converted to di- and monofunctional benzoxazines by reacting with primary amines and paraformaldehyde. The structures of benzoxazines were characterized by NMR, and FTIR spectroscopic analyses. Moreover, the curing behavior and thermal stabilities of benzoxazines and related polybenzoxazines were investigated by differential scanning calorimeter (DSC) and differential thermal analysis (DTA) in combination with thermogravimetric analysis (TGA). These studies revealed that the difunctional monomer has only 2% mass loss during curing and the obtained polybenzoxazines exhibited high char yields such as 60% at 800 ⁰C.