High-performance naphthalenediamine-based polybenzoxazine and its cured epoxy resin

To obtain thermosets with high performance, a 1,5-naphthalenediamine (NDA)-based benzoxazine (NB) is successfully synthesized and used as a novel hardener for diglycidyl ether of bisphenol-A (DGEBA). The structure of NB is confirmed by FT-IR and NMR. The curing behaviors of NB and NB/DGEBA are studied by non-isothermal DSC, and the properties of the resulting thermosets are measured by DMA and TGA. The results show that NB’s thermoset has excellent thermal–mechanical property, thermal stability, and flame retardancy, with storage modulus at 30 °C ( \( E^{{\prime }} \) ) of 2.4 GPa, 10% weight loss temperature ( T 10% ) of 366 °C, glass transition temperature ( T g ) of 279 °C, and char yield at 800 °C in nitrogen (CY) of 60.6%. NB-cured DGEBA possesses better stiffness, thermal stability, flame retardancy, and high-temperature resistance than NDA-cured DGEBA, as indicated by the 1.2 GPa higher \( E^{{\prime }} \) , 11 °C higher T 10% , 21% higher CY, and 50 °C higher T g .