Fire‐retardant synergy of bis(1‐methoxy‐2,2,6,6‐tetramethyl‐4‐piperidinyl)sebacate and melamine hydrobromide/aluminum diethylphosphinate in polypropylene

Abstract

Summary The fire‐retardant synergy of bis(1‐methoxy‐2,2,6,6‐tetramethyl‐4‐piperidinyl)sebacate (NORSM) and melamine hydrobromide (MHB)/aluminum diethylphosphinate (ADEP) in polypropylene (PP) has been studied using UL‐94 tests, limiting oxygen index (LOI) determination, and cone calorimetry tests (CCTs). The results indicate that NORSM exhibits exceptional fire‐retardant synergy with ADEP/MHB in PP. For a PP composite with 1.0 wt% of MHB and 1.5 wt% of ADEP, the LOI increased from 19.0% to 26.0%, fire retardation effectivity increased from 0.48 to 2.93, synergy effectivity was as high as 1.99, UL‐94 level was enhanced from none to V‐2, fire performance index increased from 56.4 to 84.8, and various heat release values decreased significantly when the PP composite just discussed combining 0.30 wt% of NORSM. NORSM plays a role in synergy with ADEP/MHB primarily through the following modes: radicals such as CH3O· and aminyl formed by the decomposition of NORSM; PO2·, PO·, and HPO· formed from ADEP; HBr formed from MHB; and quench active radicals such as HO· for combustion and breaking down the radical source, which terminates the chain oxidation reaction for combustion, leading to more exceptional fire retardation in the gaseous phase.