Synthesis Of Tin Dioxide,phosphate And Ammonium Molybdate By Using Pollen As A Biotemplate And Their Application In Flexible PVC

In today's society,polyvinyl chloride(PVC)has been widely applied to all areas of life and industry,as a result,it's an important significance for the study of flame retardant suppression of PVC.PVC has a great flame retardant effect at first,but due to adding a large amount of plasticizer in the machine shaping,the flame retardant of PVC have greatly reduced,releasing large amounts of smoke and toxic gases.Inorganic flame retardant is green and environmentally friendly,but the adding of it leads to the mechanical properties of the PVC declineing.Therefore,improving the compatibility between flame retardants and polymer matrix becomes a research hotspot.This article uses pollen,which has a variety of functional groups on the surface,as a template,three flame retardants based on pollen was synthesized:pollenl loaded of tin oxide(Pre-SnO2,P-SnO2),pollen loaded of ammonium phosphomolybdate(P-APM),pollen loaded of tin oxide and ammonium phosphomolybdate(P-SnO2-APM).Then we apply Pre-SnO2,P-SnO2,P-APM,Pre-SnO2,P-SnO2 to the flexible PVC,and discuss the influence for PVC flame retardant and smoke suppression performance by limiting oxygen index(LOI),cone calorimeter tests(CONE),meanwhile using universal tensile machine to test its influence on elongation at break and tensile strength.And by thermogravimetric analysis(TG),carbon residue,quenched section surface analysis,we preliminary discuss the influence of flame retardant properties and mechanical properties of PVC.The main content is divided into two parts:The first part,synthesis of Pre-SnO2,P-SnO2,P-APM,P-SnO2-APM.Through the impregnation method,use anhydrous stannic chloride,anhydrous ethanol as raw materials,prepare Pre-SnO2,P-SnO2 of micro/nano hollow reticular structure,and explore the follow influence factors:the dipping time,solid-liquid ratio,stannic chloride concentration;Make full use of the low solubility of ammonium phosphomolybdate in the nitric acid precipitation,and use ammonium molybdate as raw material,then directly synthesize P-APM of hollow reticular structure.Then H3PO4 concentration,stirring time,aging time and the join order of pollen respectively;Combined with the Pre-SnO2,P-APM synthesis method,prepare P-SnO2-APM with reticular structure.The products were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),infrared spectroscopy(FTIR)and so on.In the end,it is successful to prepare the target product by the way of precipitation and impregnation method.The second part,the products of Pre-SnO2,P-SnO2,P-APM,P-SnO2-APM are used to flame retardant soft PVC through the LOI,CONE,for the result that the total heat release and the total amount of smoke compared with PVC is reduced.Use TG,carbon residue,SEM to analysis the causes of the result,and the reason is that the tin oxide has the ability of catalytic PVC into carbon dioxide and molybdenum element has an ability of fixing carbon in the process of PVC combustion;Use universal tensile test machine to measure the mechanical properties.Results show that the mechanical properties of soft PVC,which adds flame retardant,is excellent.It is proved that it has a good compatibility between the prepared flame retardants and the soft PVC through observing quenched section surface.