Search

The possibility of layered melamine-phytate (MEL-PA) as an efficient synergist for intumescent flame retardant (IFR) is explored. The synergistic effects of MEL-PA on polypropylene (PP)/IFR composites are investigated in terms of flammability tests and combustion under forced-flaming condition. The addition of MEL-PA can effectively improve limited oxygen index (LOI) of PP composites. When 2 mass% MEL-PA is incorporated, the LOI value is enhanced from 33.0 to 35.1%. In addition, fire-retardant performance is increased with the addition of MEL-PA. The heat and smoke releases of PP/IFR are greatly reduced by MEL-PA. When IFR is partially replaced by 0.5, 1.0 and 2.0 mass% MEL-PA, total smoke production values are decreased by 27.2%, 34.8% and 57.6%, respectively. Raman spectra analysis indicates that the adding of MEL-PA results in higher graphitization degree of char layer. This work proves that MEL-PA and IFR have a good synergistic effect on flame-retardant PP. [ABSTRACT FROM AUTHOR]

• A novel bio-based flame retardant was synthesized via a simple ionic reaction. • The synergistic effects of IFR on combustion behaviors of PLA were explored. • APP/ATMP-NA-Fe endowed PLA with excellent flame-retardant performance. The high flammability and severe melt-dripping during the combustion are the most marked fire hazards for polyesters, such as polylactic acid (PLA). In this work, a bio-based flame retardant (ATMP-NA-Fe) was successfully synthesized by a simple aqueous ionic reaction by using amino trimethylene phosphonic acid (ATMP), nicotinamide (NA) and FeCl 3 •6H 2 O as raw materials. The ATMP-NA-Fe and ammonium polyphosphate (APP) have good synergistic effects on improving the flame-retardant performance and retarding the combustion melt-dripping of PLA. With a 10 wt% total loading of ATMP-NA-Fe and APP (1:1), the limiting oxygen index value of corresponding PLA composite (PLA3) increases from 20.1% to 32.8%, and it passes UL-94 V-0 rating without melt dripping. The cone calorimetry results show that compared with pure PLA, the peak heat release rate, total heat release and average mass loss rate of PLA3 are reduced by 66.4%, 14.9% and 76.7%, respectively. Via the analysis on the condensed and gas phase products, the flame-retardant mechanism of PLA/APP/ATMP-NA-Fe composites is proposed. This work provides a new approach for improving flame-retardant performance of PLA and promoting the utilization of renewable resource. [ABSTRACT FROM AUTHOR]