| Under the guidance of zoology design theory,which advocatcd that the material and environment should develop in phase,surface modification of Ca(OH)2 and its synergistic agent used as flame retardant in PE materials were studied in this paper,and the rheological behavior of PE/Ca(OH)2 composite was discussed by AR2000 rheometer.First of all,four kinds of coupling agents which were aluminate ester,stearic acid, octadecyl alcohol and rare earth were selected to modify the Ca(OH)2 by melt-blending. The effect of different coupling agents and the dosage of Ca(OH)2 to the PE/Ca(OH)2 composite material in rheological character were discussed by AR2000 rheometer,as well as the inner network structure of the composite materials.The results showed that the modifying effects of rare earth and stearic acid coupling agents to Ca(OH)2 were better than aluminate ester and octadecyl alcohol;and the best dosage of modified Ca(OH)2 was 30 to 40 percent when used rare earth as the coupling agent.Secondly,rare earth coupling agent was used to modified the surface of Ca(OH)2 and Mg(OH)2.The effects to the flame retardant character of composite materials were examined by means of OI,SEM,and TG methods.The results indicated that some synergistic function in flame retardant came up when used Ca(OH)2 and Mg(OH)2 compounds to fill the PE materials.The flame retardant level of PE/Ca(OH)2/Mg(OH)2 composite came to FH-1 when the dosage of Ca(OH)2 and Mg(OH)2 were 20 percent and 15 percent,respectively.This level was the same as PE/Mg(OH)2 composite when the dosage of Mg(OH)2 was 35 percent,illuminating that we could used low-cost Ca(OH)2 to replace some Mg(OH)2.Thirdly,ammonium polyphosphate(APP),MoO3,expandable graphite(EG)and micro-capsulated red phosphorus(MRP)were used as the synergistic agent of flame retardant of PE/Ca(OH)2 composite.The mechanics and flame retardant characters were deeply studied by TG in nitrogen circumstance.The results showed that importing a few synergistic agent could advance the OI of the composite materials,and more solid and steady charcoal layer which had some flame retardant effect,would build during the process of thermal oxidation degradation.Fourthly,The effects of Ca(OH)2 and MRP compounds,which were used as filling materials to the mechanics and flame retardant characters of PE/Ca(OH)2/MRP composite materials were discussed.The resuslts indicated that the OI of PE/Ca(OH)2/MRP came to 27.5 percent,and the synergistic OI came to 4,the flame retardant test past FH-1 level, and the mechanics capability could be assured.It showed that Ca(OH)2 and MRP had good synergistic flame retardant effect.Fifthly,ternary compound of flame retardant agent,namely,Mg(OH)2/Ca(OH)2/MRP, was also studied.The results showed that the OI of the PE composite materials all came up to 27 percent when the dosage of the compound inorganic powder[Ca(OH)2:Mg(OH)2 =4:3]was more than 40 percent,while the OI came to 29.5 percent when the dosage of the ternary compound was 60 percent,especially.
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