Filtern
Erscheinungsjahr
- 2011 (2)
Dokumenttyp
Sprache
- Englisch (2)
Referierte Publikation
- ja (2) (entfernen)
Schlagworte
- Metal oxide (2) (entfernen)
The known flame-retardant synergism between phosphorus-based additives and metal oxides, already used for petroleum-based plastics, has been extended to bio-based materials. The pyrolysis and the flame-retardancy properties of aluminium phosphinate (AlPi) in combination with nanometric iron oxide and antimony oxide on a poly(3-hydroxy-butyrate-co-3-hydroxyvalerate)/poly(butylene adipate-co-terephthalate) (PHBV/PBAT) blend were investigated. Better fire retardancy, ascribed to increases in intermediate char, favoured improvements in the UL 94 classification. Both the phosphorus and the nanofiller components participate simultaneously in the flame-retardancy mechanism: the first acting as flame inhibition in the gas phase, and the second promoting cross-linking in the solid phase. Redox reactions between iron oxide and the phosphinate additive were confirmed by XRD analysis and provided further evidence of the activity of metal compounds.
The pyrolysis and the flame retardancy of poly(butylene terephthalate) (PBT) containing aluminum diethylphosphinate (AlPi) and nanometric Fe2O3 were investigated using thermal analysis, evolved gas analysis (Thermogravimetry-FTIR), flammability tests (LOI, UL 94), cone calorimeter measurements and chemical analysis of residue (FTIR). AlPi mainly acts as a flame inhibitor in the gas phase, through the release of diethylphosphinic acid. A small amount of Fe2O3 in PBT promotes the formation of a carbonaceous char in the condensed phase. The combination of 5 and 8 wt% AlPi, respectively, with 2 wt% metal oxides achieves V-0 classification in the UL 94 test thanks to complementary action mechanisms. Using PBT/metal oxide nanocomposites shows a significant increase in the flame retardancy efficiency of AlPi in PBT and thus opens the route to surprisingly sufficient additive contents as low as 7 wt%.