Research On Modified Ammonium Polyphosphate On Flame Retardant Polypropylene Composite Materials

Polypropylene(PP)is one of the most widely used general-purpose thermoplastic.It has many advantages such as low density,good molding process property,excellent mechanical properties and heat resistance.But its oxygen index is only about 17-18%,which made it poor used in many fields.Intumescent flame retardants(IFR)has the characteristics of the efficient and environmental,contemporary requirements.It conformed with the future development trend of flame retardants,which make it has a wider field of application in daily necessities,electronic appliances,communications,transportation,and building.But IFR has the defects of moisture absorption and migration exudation,and the issue of the compatibility between polypropylene and intumescent flame retardant,which make the falling on the mechanical properties of the material,limit the flame retardant polymer application in engineering.In order to overcome these problems,the widely method is modification of IFR.In this paper,we use the melamine formaldehyde resin encapsulated polyphosphate.Ratio of melamine and formaldehyde,the pH,temperature and time on the pre-polymerization process;and the mass ratio of prepolymer/polyphosphate,the pH,temperature and time on the encapsulated process are investigated.Through the investigate the optimum process conditions were determined,including ratio of melamine and formaldehyde is 1/2.5,prepolymerization pH is 8.5,the prepolymerization temperature 80?,the time of prepolymerization was 20 minutes · ratio of prepolymer/polyphosphate is 1/3,encapsulated pH is 5,the encapsulated temperature 85 °C,the time of encapsulated was 2 hours.Microencapsulated polyphosphate solubility in water is 0.1514g/100mL,and the pH of the aqueous solution is 5.87.The FTIR shows the melamine formaldehyde had containing polyphosphate;The TG and measurements indicate the thermal stability and water resisting property had been improved obviously.Ratio of Microencapsulated polyphosphate and pentaerythrite is 3/1.The mixture made the IFR the expansion is 112.09cm3/g and the carbon yield ratio is 54.21%after heated preservation under 500? for 5min.Glycidyl methacrylate/styrene graft modification of PP was used as compatilizer to improve the properties of the compatibility between polypropylene and intumescent flame retardant,The influence of The addition of IFR and compatilizer on the properties of flame retardant PP composites was investigated.UL94 vertical combustion test,MFR,SVT,DSC and non-notched impact strength measurements indicate the PP has the practical application.