Toughening And Flame Retardant Of High Impact Polystyrene

This article was based on high impact polystyrene as the research subjects.It was widely used due to good processing properties and electrical insulation.However,the most obvious disadvantage of HIPS was its high flammability and opious smoke-emitting property upon combustion.The oxygen index of HIPS resin is only 18%.Thus,it is important to endow them with fire retardant and smoke suppressing properties.The oxygen index was improved,but the impact strength was decreased after adding flame retardant.So the blending material was toughened on the basis of the flame retardant.The flame retardancy and impact performance was balanced to achieve the optimal.In this study,flame retardant HIPS materials were prepared by double screw extruder.The effect of different amount of flame retardant,different kinds of toughener,different amount of toughener,FB,OMMT on flame retardance and mechanical properties of blending material was studied.The best formula system is discussed.The performances of modified HIPS on the combustion performance,mechanical properties,and rheological properties were evaluated.And microstructures were observed by scanning electron microscopy observation?SEM?and also thermo-gravimetric analysis.The main results of this paper are as follows:The flame retardancy effect of Sb₂O₃ with DBDPE was better than only DBDPE.The comprehensive performance of blending materials is better when DBDPE and Sb₂O₃ quality ratio of 2:1.Based on this,Retardant effect is getting better when increasing the dosage.Oxygen index is 29.5 and Vertical burning reached UL94V-0 when the amount of DBDPE/Sb₂O₃ in 18/9.But the impact strength decreased sharply,low to 6.78kJ/m2.So it's necessary to guarantee of combustion performance at the same time to improve the impact performance of blending materials.Three kinds of elastomer,such as SBS,MBS,POE were chosed as toughener of flame retardant HIPS.The oxygen index of the blending material is the highest when added 10 parts of toughening agent SBS,the oxygen index is 28,Vertical burning reached UL94V-O.The impact strength is the highest,to 7.35kJ/m.The rheological property,thermal stability are relatively stable,flame retardant HIPS blend showed shear thinning pseudoplastic fluid characteristics by the study of melt flow rate and capillary rheometer.The effect of different amount of toughener on flame retardance and mechanical properties of blending material was discussed.Added SBS with 5,10,15,20,with the increase of SBS,Oxygen index is gradually declined,The vertical combustion is maintained UL94V-0.The impact strength is increase.The tensile strength and bending strength are also declined.SEM analysis,SBS had good compatibility with substrate material after added SBS,ections with a grid structure.it's beneficial to improve the toughness of the blend material.When the SBS is 15,its comprehensive performance is best.It can inhibits droplet and control the amount of smoke after added FB.Oxygen index increased slightly.Other performance is stable.Oxygen index increased to 29.5 when the use of OMMT was 3phr.The vertical burning level of blending system remains UL94V-0.SEM analysis,HIPS/DBDPE/Sb₂O₃/SBS/FB/OMMT system burner surface showed continuous and dense carbon layer,what cut off oxygen to prevent heat transfer.The result showed that OMMT,FB and HIPS/DBDPE/Sb₂O₃/SBS achieved a synergistic flame retardant effect.