Preparation And Application Of LDHs As Flame Retardants On Flexible PVC

Several LDHs flame retardants have been preparated by coprecipitationmethod, ion-exchange method and calcine-recovering method, which werecomposed of the elements and groups with excellent flame retardant effect, such asCa, Mg, Al, Zn, borate, et al. The flame retardant and mechanical properties of theflexible PVC mixing LDHs was studied. Experiment results show that:1. The particle size of the prepared MgAl-CO₃^2--LDHs by coprecipitationmethod is about200nm and borate pillared MgAl-LDHs by ion-exchange method isabout150nm. The OI of flexible PVC mixing5phr. MgAl-CO₃^2--LDHs is28.4%and mixing5phr. borate pillared MgAl-LDHs is29.2%. The mechanical propertiesof flexible PVC mixing less than5phr. MgAl-LDHs is not decreased obviously.2.The particle size of the prepared ZnMgAl-CO₃^2--LDHs by coprecipitationmethod is about300nm-500nm. The technological conditions were investigated byexperiments were as follows: reaction temperature is65℃, the Zn/Mg/Al ratio is1:1:1, the solution concentration is [Al3+]=0.48mol/L. The preparation ofZnMgAl-CO₃^2--LDHs by coprecipitation method was carried out by middle-scaletest. The preparation of borate pillared ZnMgAl-LDHs was carried out byion-exchange method and calcine-recovering method. The crystallinity of boratepillared ZnMgAl-LDHs prepared by ion-exchange method is better than that bycalcine-recovering method.3. The OI of flexible PVC mixing5phr. ZnMgAl-CO₃^2--LDHs is29.3%andmixing5phr. borate pillared ZnMgAl-LDHs is30.1%. The mechanical properties offlexible PVC mixing less than5phr. ZnMgAl-LDHs is not decreased obviously.4. The particle size of the prepared CaMgAl-CO₃^2--LDHs by coprecipitationmethod is about50nm-200nm and borate pillared CaMgAl-LDHs by ion-exchangemethod is about30nm-150nm. The OI of flexible PVC mixing5phr.CaMgAl-CO₃^2--LDHs is30.7%and mixing5phr. borate pillared CaMgAl-LDHs is31.0%. The flame retardant effect of borate pillared CaMgAl-LDHs is the best inthis paper. The mechanical properties of flexible PVC mixing less than5phr.CaMgAl-LDHs is not decreased obviously.