Synthesis and Characterization of Bio‐Based Benzoxazine Monomer for Metal Sensing Applications and to Form Fire‐Retardant Polymer

ABSTRACT A novel fluorescent benzoxazine (Bz) is synthesized from bio‐based amines, furfuryl amine, 2, 7‐dihydroxy naphthalene, and paraformaldehyde and characterized using NMR and IR spectroscopy. The Bz emits white light under UV irradiation, which is sensitive to the presence of almost all transition metal ions exclusively, either by reducing the intensity or by completely shutting off the white light emission. This nature may be used for sensing the respective metal ions. The DSC thermogram shows an exothermic peak at 255°C, indicating the curing of Bz by ring opening polymerization, which is confirmed by the FTIR spectra of poly Bz cured at different temperatures. Poly Bz has high thermal stability and hydrophobicity with an increase in curing temperature accounting for its potential application in aerospace and electronic applications. Additionally, as the polymer contains furfuryl groups, poly Bz has low dielectric constant and dielectric loss values, ideal in materials for uses like 5G technology and high‐frequency circuits that demand fast signal transmission and low energy loss. This study demonstrated the synthesis of bio‐based novel Bz monomer, which has fluorescent behavior and can be used for the life cycle analysis of the polymer.