Study On Flame Retardant Polyurethane

The flame retarded polyurethane were prepared by different reactive flame retardants.The content of flame retardant on the structure and morphology of polyurethane and flame retardancy and mechanical property were studied.The work included two parts:(1)A series of PU elastomers were prepared using different content of bromine containing polyol and phosphorus containing polyols.The structure and properties of PU elastomers were studied.(2)The bromine and phosphorus containing polyol was synthesized through step polymerization by dichlorophenylphosphine oxide and dibromoneopentyl glycol(PBr).The content of PBr on the structure and porperties of polyurethane rigid foams were studied.With increase in the amount of bromine containing polyol RB79,the degree of hydrogen bonding and mechanical properties of PU elastomers were decreased first and then increased.The microphase separation degree was decreased and thermal properties reduced when the amount of RB79 increased.With increase in the amount of bromine containing polyol RB79,the limited oxygen index(LOI)improved.When rised the amount of phosphorus containing polyol OP550,the microphase separation degree,the thermal properties and mechanical properties of PU elastomers became lower.When the amount of OP550 increased,the LOI significantly enhanced.The char residues of flame retardant PU elastomers were studied by FTIR,XPS and SEM.The results showed that the char residue was composed of polyaromatic and polyphosphate compound.The morphology of the char residue was intumescent and enclosed.With increase in the amount of PBr,the compressive strength and average size of PU rigid foams were decreased first and then increased.When the amount of PBr was increased,the LOI enhanced,but the smoke density also increased.The char residues of flame retardant PU elastomers were studied by FTIR and SEM,and the results showed that the char residue was made up of polyaromatic and polyphosphate compound.The morphology of the char residue was intumescent and continuous.