Effect of addition of aluminum phosphinate as fire retardant in a PBT vitrimer

Abstract

This work investigates the effect of flame-retardant additives on the thermo-mechanical and dynamic properties of poly(butylene terephthalate) (PBT) vitrimers. The vitrimers were synthesized and compounded in a single step by reactive extrusion from commercially available PBT, an epoxy resin, a zinc-based transesterification catalyst, and aluminum phosphinate (AlPi) as a conventional flame retardant additive. We demonstrated that the presence of AlPi in relatively large amount (20 wt.-%) is compatible with the formation of the vitrimer network and does even play the role of a transesterification (co)catalyst accelerating the exchange reactions and improving the processability of the vitrimer. UL-94 flammability tests also confirm the effective role of AlPi as flame retardant in vitrimer.