Study On Preparation And Properties Of Halogen-free Flame Retardant Polypropylene

Polypropylene(PP)is a widely used commodity thermoplastic with a number of desirable properties,which is widely used in the area of electrical appliance,the automotive industry and so on.with its scope of application increasing demands of their fire-retardant properties have been higher and higher.Whereas the protection of the environment,application of the halogen flame retardant had been restricted,and the efficiency of inorganic flame retardant is lower with the drop of mechanical property.So it is essential to research a flame retardant PP with higher efficiency, environment-friendly and excellent comprehensive performance.Influences of different fire-retardant synergistic agents on temary compounding intumescent flame retardant were explored in this paper,researched the properties of glass fiber enhanced the fire-retardant PP,and achieved the halogen-free flame retardant polypropylene composites with excellent comprehensive performance in the end.Main contents and results as follow:(1)Ammonium polyphosphate(APP)with high degree of polymerization, melamine phosphate(MP),pentaerythrite(PER)has composed intumescent flame retardant in this paper.Synergy of APP and MP and the properties effect of PER in the composites had been researched.The results indicated that PP has a better fire retardant property when APP/MP/PER=(0.35～0.49)/(0.21～0.35)/(0.3～0.4).The LOI of PP/AM-IFR fire-retardant composites can reach to 27%when content of AM-IFR which had been composed of APP/MP/PER=0.40/0.25/0.35 is 15%,the fire can put out by itself in the air,and the mechanical property of composites is equal with pure PP.Further analysis showed that MFR of PP can be improved largely by AM-IFR,It can increased the heat-resistant deformation temperature,cut down the crystal size of composite material,promoted the carbon of PP,and widen the scope of thermal degradation temperature.(2)Na-MMT,OMMT,4Azeolite were used into the PP/AM-IFR composites as flame retardant synergistic agents.The synergistic fire retardant action,thermal stability,and shape of charcoal layer were study by using Limiting oxygen index(LOI),thermogravimetric analysis(TGA),scanning electronic micrograph (SEM),etc.The structure of PP/AM-IFR/OMMT nano-composites has been researched byⅩ-ray.The result showed that Appropriate contents of Na-MMT, OMMT,4Azeolite lead to better flame retardant synergy of PP/IF-AMR composites, catalyzed the process of char forming and contribute to the high-quality carbon formation.(3)The properties of glass fiber on halogen-free flame retardant polypropylene were explored.The results showed that the property of mechanical,heat distortion and thermal stability can be effectively improved with the glass fiber contents increasing, but the property of flame-retardant was decreased and the MI was little influenced.