The environmental-friendly intumescent flame retardant was constructed by the combination of piper-azine pyrophosphate(PAPP)and chitosan(CS).The intumescent flame retardant polypropylene composites(IFR/PP)were prepared by melt blending.The flame retardants properties and mechanisms of IFR/PP were studied by methods such as oxygen index,cone calorimeter,thermogravimetric analysis and mechanical proper-ties test.The results showed that when the total amount of expansion flame retardant was 30wt％,and the mass ratio of PAPP to CS was 5∶1,the LOI value of IFR/PP was 35.5％,and UL-94 reached V-0 grade.The residue at 800 ℃ was 13.34wt％,the peak heat release rate(pHRR)was reduced from 1345.01 kW/m2 to 83.04 kW/m2,and the tensile strength was reduced by 39.9％.The SEM test results of residual carbon showed that the addition of CS promoted the formation of an expanded carbon layer,resulting in a denser and more uniform carbon layer during material combustion,which improved flame retardant property and smoke suppression abil-ity.PAPP and CS have a good synergistic flame retardant effect.
维普
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