Biobased phosphorus PIN FRs for PA66

Lab study of DOPO-functionalised biobased muconic acid as a reactive phosphorus PIN flame retardant for polyamide-66. Bio-sourced trans-3-hexenedioic acid (t3HDA) was reacted with DOPO (dihydro- 9-oxa- 10-phosphaphenanthrene- 10-oxide, an organophosphorus PIN FR building block) in dimethyl formamide (solvent and catalyst), followed by hydrolysis by lithium hydroxide, washing and precipitation. This was then copolymerised into polyamide-66, resulting in 5 – 11% loading of DOPO. Results showed that heat release rate was reduced by around 1/3 by this bio-based reactive PIN FR strategy without significantly deteriorating the polyamide mechanic performance characteristics.

“Leveraging the bio-enabled muconic acid platform via phospha-Michael-addition: intrinsically flame retardant nylon-66/DOPO copolymers”, P. Carter et al., RSC Sustainability, 2024, 2, 2968 https://doi.org/10.1039/d4su00184b