Study Of Intumescent Flame Retardant Polyethylene Foam Structure And Properties

In this paper,based on the principle of flame-retardant chemical expansion,designed three typical foamed low density polyethylene(LDPE)chemical expansion flame retardant system.Focus on the influence of the flame retardant properties of the kind,amount and conditions of the combustion system intumescent flame retardant foam LDPE,mechanical properties and cell structure;by optical microscopy(POM)and scanning electron microscopy(SEM)analysis and characterized by means Effect of different carbon source as an expansion set of components on the expansion layer and carbon layer structure system;the use of scanning electron microscopy(SEM),thermal gravimetric analysis(TG)and the limiting oxygen index(LOI),etc.on the combustion mechanism of foaming system be research.The main conclusions are as follows:Lignin/ammonium polyphosphate(APP)IFR LDPE foam,the foam material expands when the flame retardant system in the amount of lignin and APP ninety past eight p.m.parts,the limiting oxygen index of flame retardant level of 27%,vertical burning test rating to FV-0level is modified to become flammable foam flame retardant materials.Lignin APP/APP /LDPE foam modulus has little effect,but reduces the toughness and fracture strength of the foam material.With the increase of the amount of foam flame retardant system in the APP,lignin/APP/LDPE intumescent foam cell diameter becomes small,increase in cell number,cell size becomes uniform.Carbon dense layer level has been markedly improved flatness carbon layer decreases gradually reduce carbon cell layer.Starch/APP IFR LDPE foam,when the amount of starch APP 20:80 parts,the limiting oxygen index of flame retardant foam level of 27%,vertical flame test rating to FV-0 grade starch/APP/LDPE intumescent flame retardant foam cell diameter,cell wall thinning.Highest carbon layer covers the extent and degree of structure after combustion dense foam surface.Lignin/MCA/APP IFR LDPE foam,MCA added,the expansion and modulus of rigidity retardant foam LDPE increased cell diameter increases,the cell wall thinning.When the amount of APP and MCA 60:50,the limiting oxygen index system reached 28.1%,thevertical combustion grade reaches LV-0 levels,without significant melt dripping during burning.700 o C residual carbon content increased from 14.2% to 32.3%,adding IFR MCA after burning charcoal layer LDPE foam structure is more smooth and compact,so that the effect of flame retardant expansion foam system has improved significantly.When the conditions for the mold temperature at 160 o C-170 o C,molding pressure is between10MPa-12 MPa,lignin/MCA/APP IFR LDPE foam mechanical properties and flame retardancy best.