Posted on 19/06/2024 in Fire Safety 2024
Polymer DOPO FR for polyamide (PA6)

Polymeric DOPO-based phosphorus PIN FR achieved UL94 v-0 (3.2 mm) in polyamide at 0.3% total phosphorus content. The phosphorus-nitrogen polymeric PIN FR was synthesised by melt polymerisation of a DOPO-derivative (DDP*) with DMDA** and caprolactam (a nitrogen-containing chemical used in polyamide production). In polyamide-6 – PIN FR compounds with phosphorus content of 0.3%, UL 94 V-0 (3.2 mm) was achieved (V2 for neat PA6) and LOI of 25.8% (21.7% for PA6). With 0.5%P, LOI reached nearly 29% and peak heat release rate was more than 35% lower than for neat PA6. The mechanical properties of the polyamide were however considerably deteriorated by compounding with the polymeric PIN FR.

* DDP = 9,10-dihydro-10-(2,3-dicarboxypropyl)-9-oxa-10-phosphaphenanthrene 10-oxide (a DOPO derivative)

** DMDA = decamethylene diamine

“Polymer-type flame retardants based on a DOPO derivative for improving the flame retardancy of polyamide 6: Preparation, properties and flame retardancy mode of action”, B. Liang et al., Polymer Degradation and Stability 225 (2024) 110807,

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