Introduction of the first commercial biobased benzoxazines for the manufacturing of fibre reinforced polymers†

Benzoxazines are a promising material class due to their flexible molecular design, high thermomechanical properties, and inherent flame retardancy. Especially the latter makes them interesting for all kinds of applications, for example lightweight constructions in the transportation sector. The first commercial benzoxazines were based on bisphenol and aniline, petrochemical resources produced from crude oil. However, due to the growing demand for more sustainable materials the use of biobased resources for benzoxazine synthesis has been thoroughly investigated in the past years. In this work, we present the first commercial benzoxazines that consist of biobased compounds. After analysing the curing behaviour of these new resins using thermal analysis, polymers are manufactured and characterised from them. Finally, the resins were used for manufacturing fibre-reinforced polymers (FRP) for flame-retardant lightweight applications. Thermomechanical and combustion analysis showed that the polymers achieve high flexural moduli up to 2.8 MPa and glass transition temperatures of 100 °C and 141 °C. In addition, the biobased benzoxazines have promising flame-retardancy due to intumescence, resulting in high LOI values of 31.4 ± 0.2 and 33.3 ± 0.1%