The Research On Non-halogen Flame-retardant PC/ABS Blend

Because of innocuity and little smoke, the halogen-free flame-resistant PC/ABS alloy with excellent mechanical properties and smooth surface get a wide range of application. However, there are some problems, such as low efficiency, decreasing mechanics properties, producing melt when burning, for the common halogen-free flame retardants for PC/ABS alloy. In order to improve mechanics properties and achieve flame-resistant purpose, PC/ABS blend system we modified by adding a new halogen-free flame retardants. Finally, mechanical properties of the materials were investigated.Firstly, PC and ABS were directly blended and the effect of the categories and contents of PC and ABS on the mechanical and thermal properties of the PC/ABS alloy were investigated. Besides, the influences of the craft conditions on the properties of the PC/ABS alloy were studied. It was found that PC/ABS (70/30) alloy exhibited optimal properties when the liquidity of PC was similar to ABS. PC/ABS alloy did not only show the thermal endurance and intensity of PC, but also the liquidity of ABS. Moreover, the stress cracks of the materials were avoided. Those result in the higher cost performance of materials. When the content of ABS is 30%, the PC/ABS alloy system reveals the synergistic effect of increasing toughness.Secondly, methyl methacrylate/butadiene/styrene copolymer (MBS) was used to modify PC/ABS alloy, and then thermal analysis and scanning electron microscope were carried out to characterize the compatibility between PC and ABS. The results showed that PC is compatible with ABS in part, while compatibility between PC and ABS obviously enhanced because of MBS. After MBS was added, the toughness of the alloy distinctly increased and the mechanism is primarily due to the particle vacancies which cause the shears of the matrix to absorb impact energy.Thirdly, oxygen index number method and level perpendicular burnable method were used to investigate the influence of several kinds of common halogen-free flame retardants on flame-resistant properties of the PC/ABS. It was found that the mixture of triphenyl phosphate (TPP) and four benzene A types two phosphoric acid ester (BDP) (3:2) have synergistic flame retardant effect for PC/ABS alloy, and can retain the thermal endurance of the composites. Further more, polytetrafluoroethylene was added to the alloy to avoid the melt from falling when burning. It was found that a little amount of polytetrafluoroethylene in the system can effectively prevent the melts of PC/ABS from falling, and can improve the flame retardant properties of the composites.Finally, the influence of the main compositions in the system on the mechanics property of the composites was investigated, and the system of the flame-resistant PC/ABS alloy without halogen was optimized. Appropriate MBS and compound flame retardant can make composite material have better tenacity, rigidity, flame-resistant and thermal properties. A little talcum powder which activated by aluminic acid ester, the size stability of the materials is increased.Owning to low smoke, innocuity, environment friendly and excellent mechanics properties, the new flame-resistant PC/ABS alloy without halogen will have good applied foreground.