Enhancement in fire retardancy of thermoplastic polyurethane: Effect of pentaerythritol derived phosphorous based bicyclic polymer on the flammability

Abstract

1-oxyphospha-4-hydroxymethyl-2,6,7-trioxabicyclo [2.2.2] octane (PEPA) was synthesized successfully in producing a PEPA-based monomer having an acrylate group and its polymers. Nuclear magnetic resonance (NMR), ¹H, and ³¹P spectra were used to establish their structural integrity. Thermogravimetric analysis (TGA), the limited oxygen index (LOI), and the UL-94 test were used to examine the thermal characteristics and flame retardant behavior of the systems with 15 wt% of flame retardants (PhosPTPU₁₅). Thermoplastic polyurethane (TPU), the results reveal that LOI increases from 19–27.8% with incorporation of 15 wt% PhosPTPU₁₅. SEM-EDX was used to evaluate the morphology of the TPU and its blend, which exhibits that with the incorporation of PhosPTPU₁₅ the blend showed compact morphology and supported the condensed phase mechanism of the blends.