Polymerization and characterization of benzoxazine synthesized from para-diamines and their epoxy composite for electronic and aerospace applications

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We have created a resilient, non-corrosive, insulating substance for electronics and aeronautics by synthesizing benzoxazine (Bz) from diamine, phenol, and paraformaldehyde. The synthesized Bz is characterised and polymerised (PolyBz) by curing at 150, 200, 250 and 300 °C. PolyBz exhibited significant dielectric loss of 5.15, 6.59, and 6.36 at 1 MHz and high dielectric constants of 3.05, 1.70, and 1.69 at 50, 125, and 150 °C respectively. Better passive corrosion behaviour is demonstrated by electrochemical impedance measurements for the polyBz cured at 300 °C. Epoxy composites at various compositions of Bz were made and characterised. The composites were found to be stable upto around 350 °C. The crosslinking of Bz with epoxy was confirmed with the disappearance of oxazine peak around 930–980 cm−1 in Infrared spectroscopy. The tensile strength of epoxy composite is increased to 3600 N for 6 % Bz from 1500 N for 4 % Bz, indicates that Bz functions as a cross-linking agent. It was found that the composites' water contact angle increases from 56 to 90° from 0 to 6 % of Bz with epoxide. It has been demonstrated that the Bz composite is a promising material for the above said applications.