Abstract:
Al(H
2PO
2)
3 was introduced to prepare a series of Al(H
2PO
2)
3/thermoplastic polyurethane composites (Al(H
2PO
2)
3/TPU) by melting blending technology. The flame retardancy and thermal stability of Al(H
2PO
2)
3/TPU composites were respectively investigated by limiting oxygen index (LOI), vertical burning test (UL-94), cone calorimeter, TG and SEM, the mechanical test was applied to research the effect of Al(H
2PO
2)
3 content on the mechanical properties of Al(H
2PO
2)
3/TPU composites. Flame retardancy results show that Al(H
2PO
2)
3 can effectively enhance the flame retardancy of Al(H
2PO
2)
3/TPU composites. 20wt% Al(H
2PO
2)
3 makes Al(H
2PO
2)
3/TPU composites UL-94 reach V-0 rating with LOI of 30.5vol%. TG test reveals that loading of Al(H
2PO
2)
3 will decrease the decomposition temperature of the composites while significantly enhance the char residue of Al(H
2PO
2)
3/TPU composites. The cone calorimeter results show that Al(H
2PO
2)
3 can significantly decrease the peak of heat release rate (pHRR) and total heat release (THR) of Al(H
2PO
2)
3/TPU composites, and increase the fire safety of the composites. pHRR and THR values of Al(H
2PO
2)
3/TPU composites with 20wt% Al(H
2PO
2)
3 loading are decreased 65.7% and 20.2% respectively compared with virgin TPU. SEM test indicates that char residue of Al(H
2PO
2)
3/TPU composites are significantly enhanced. TGA-FTIR was used to investigate flame retardant mechanism of Al(H
2PO
2)
3/TPU composites, which indicates that Al(H
2PO
2)
3 could promote the char formation of volatilized products of TPU molecular in combustion process, and reduce the production of combustible gas and enhance the flame retardancy of Al(H
2PO
2)
3/TPU composites.
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