Hyperbranched phosphorus flame retardants
Scientists successfully synthesised multifunctional P-based hyperbranched polymeric flame retardants (hb-FRs) with varying oxygen-to-nitrogen (O : N) content and characterised them via 1H and 31P NMR and GPC.
Their miscibility in epoxy resins (EP) and impact on glass-transition temperatures (Tg) were determined via differential scanning calorimetry (DSC). Using thermogravimetric and evolved gas analysis (TGA, TG-FTIR), pyrolysis gas chromatography/mass spectrometry (Py-GC-MS), hot stage FTIR, flammability tests UL-94 and LOI, fire testing via cone calorimetry, residue analysis via scanning electron microscopy (SEM) and elemental analysis, detailed decomposition mechanisms and modes of action are proposed.
Increase of flame retardancy
hb-polymeric FRs have improved miscibility and thermal stability, leading to high FR performance even at low loadings. Polymeric, complex FRs increase flame retardancy, mitigate negative effects of low molecular weight variants, and can compete with commercial aromatic FRs. The results illustrate the role played by the chemical structure in flame retardancy and highlight the potential of hb-FRs as multifunctional additives.
The study is published in: Polymer Chemistry, 2019, Issue 31.
Event tip
The European Coatings Fire Forum at 6-7 November will deal with latest developments in flame retardancy and intumescent coatings and will bring you up-to-date on testing methods as well as regulation. Early-bird registration is open until 18 September 2019.
