Study On Synthesis And Flame Retarded Property Of Bromostyrene Polymers

Brominated styrene polymer as an additive-type macromolecular flame retardants are widely used in the flame retardant treatment of engineering plastics such as PBT,because of its some merits as low toxicity,good compatibility with products,no migration,etc.At present,there are few researches on brominated styrene polymers in China.Therefore,the synthesis and properties of this flame retardant were studied in this paper.In this paper,four brominated styrene polymers such as poly?brominated styrene??PBS?,brominated styrene-glycidyl methacrylate copolymer?PBS-Co-GMA?,brominated styrene-methyl methacrylate copolymer?PBS-Co-MMA?and brominated styrene-ethyl acrylate copolymer?PBS-Co-EA?were synthesized through elimination reaction and polymerization by using?-bromoethylbromobenzene as a raw material,their structures were characterized by NMR,IR and gel permeation chromatography?GPC?,and Their thermal stability was evaluated by thermogravimetric analysis.The results showed that the optimal conditions of the elimination were:n??-bromoethylbromobenzene?:n?NaOH?:n?tetrabutylammoniumbromide?:n tert-butanol)=1:5:0.05:0.22,the reaction temperature being 40?and the reaction time being 6h.Under the above conditions,the yield of bromostyrene was 96.56%;The optimal conditions of the polymerization were:w?bromostyrene?:w?azoisobutyronitrile?:w?toluene?=1:0.02:1.22,the polymerization temperature being 110?,the dropping time of the monomers being 2-3h,reaction time being 4h.Under these conditions,the yields of PBS,PBS-Co-GMA,PBS-Co-MMA and PBS-Co-EA were respectively97.6%,96.7%,90.2%and 85.3%,the Mw were 473931,715901,382187,489503,and Mw/Mn were respectively 1.736,2.204,1.696,2.029.PBS,PBS-Co-GMA,PBS-Co-EA,PBS-Co-GMA and brominated polystyrene?BPS?all have good flame retardant effect in polybutylene terephthalate?PBT?.The results of vertical burning test and LOI measurement showed that the order of their flame retardancy was BPS>PBS?PBS-Co-MMA>PBS-Co-EA?PBS-Co-GMA,while the results of cone calorimetry test showed that their order of the flame retardant effect is PBS>PBS-Co-GMA>BPS?PBS-Co-MMA?PBS-Co-EA.The thermogravimetric analysis revealed that the thermal stability of PBS,PBS-Co-GMA,PBS-Co-MMA and PBS-Co-EA were all good,T_1wt%were respectively314??316??328?and 325?,T_maxwere respectively 384??386??383?and378?,and the thermal stability of PBS-Co-GMA was slightly poor.The addition of brominated styrene polymers decreased the thermal stability of PBT,but the effect of PBS-Co-GMA was smallest.Adding brominated ethylene polymers improved the processing performance of PBT,and within a certain range,the processing performance become better with increasing their dosages,and influence of the three copolymers was more obvious.However,the addition of brominated styrene polymer reduced the mechanical properties of PBT,where the impact of PBS was smallest,followed by PBS-Co-MMA,PBS-Co-GMA,and of PBS was greatest.