Molecular design of reactive flame retardant for preparing biobased flame retardant polyamide 56

As resource and environmental issues become increasingly prominent worldwide, bio-based polyamides demonstrate appealing prospects due to their renewable and low carbon emission characteristics. The preparation of intrinsically flame-retardant polyamides by copolymerization of reactive flame retardants with biomass monomers becomes a hot research topic at present. In this work, reactive flame retardant (r-FR) is synthesized, showing excellent solubility and temperature resistance. Subsequently, flame retardant polyamide 56 (FRPA56) are prepared by one-step melt polycondensation. Specifically, when the r-FR content is 6wt%, FRPA56 has a high limiting oxygen index of 28.4%, and the vertical combustion reaches V-0 level, demonstrating excellent flame-retardant performance. Moreover, FAPA56 also owns outstanding temperature resistance and mechanical properties even with a r-FR content of 8wt%, in which the melting temperature and tensile strength are 246.1 °C and 71.05 MPa, respectively. This work develops an effective strategy for constructing intrinsically flame-retardant polyamide material, which can meet the requirements of engineering plastics and exhibit satisfactory performance in the field of textile.