A fully bio-based benzoxazine as latent catalyst for bisphenol A/aniline-based benzoxazine

Lowering the curing temperature has always been one of the research focuses of polybenzoxazine. In this work, a fully bio-based phenolic hydrogen containing benzoxazines (PF) with high polymerization activity was conveniently synthesized from pyrogallol, furfurylamine and paraformaldehyde through a modified route. The structure of PF was confirmed by FT-IR and NMR. PF was used as a latent catalyst for the traditional bisphenol A/aniline-based benzoxazine (BA), and thermosets with different PF contents were prepared. The influence of PF on the polymerization temperature, thermal and mechanical properties , thermal stability and flame retardancy were symmetrically studied through DSC , DMA and TGA , respectively. The results showed that both the onset exothermic temperature ( T onset ) and exothermic peak temperature ( T p ) decreased obviously with the increase of PF content. The glass transition temperature ( T g ) and crosslinking densities of the thermosets positively correlated with the PF content, while the storage modulus showed a maximum when PF content was 2.5 wt%. The thermal degradation temperatures and char yields of the thermosets were also improved continuously as PF content increased. In brief, by adding a small amount of PF (≤10 wt%), the overall performance of BA resin could be effectively modified.