| Polypropylene (PP) has broad applications in electronics,architectural materials, cars and so on, due to its excellent comprehensiveproperties. However, PP is flammable and has poor ultraviolet (UV)aging resistance, so it is necessary to improve the flame retardancy andUV aging resistance of PP in order to expand its application. In this paper,flame retarded and UV aging resistant PP (FRAPP) compositescontaining PP, elastomer, flame retardant, hindered amine light stabilizerand sepiolite (SP)have been prepared by Melt Extrusion.The effect offlame retardant, elastomer and hindered amine light stabilizer on flameretardancy, mechanical and UV aging properties of FRAPP composites isinvestigated. The thermal decomposition performance and residual charmorphology of flame retardant PP system is investigated bythermogravimetric analysis (TGA) and scanning electron microscopy(SEM). The UV oxidative degradation performance of FRAPP system is investigated by fourier transform attenuated total reflection infraredspectroscopy (ATR-FTIR). Our study provides the oretical guidance forthe preparation of high-performance FRAPP composites. In this paper,the following works have been done:Firstly, the effect of Tetrabromobisphenol A bis (dibromopropylether)(TBAB) and Bis [3,5-dibromo-4-(2,3-dibromopropoxy) phenyl]sulphone (TBSBPE) to PP/BFR system is compared, the results showflame retardancy and mechanical properties of TBSBPE-flame retardantPP system is better, but the impact performance is poor. So toughenTBSBPE-flame retardant PP system by adding EPDM, the results showsmall amount of EPDM improve the impact strength of system, while thelimiting oxygen index（LOI）value is unchanged, but when the amount ofEPDM is more than3wt%, flame retardancy of system is decreased, dueto the TBSBPE is failure to flame retardance of EPDM.Secondly, the effect of EPDM and EPDM-g-MAH to PP/IFR systemis compared, the results show the effect of EPDM-g-MAH on themechanical properties of PP/IFR system is significant. While the amountof IFR is unchanged and SP is added to PP/EPDM-g-MAH/IFR system,the LOI of the system is increased obviously, the char yield is increasedand the flame-retardant efficiency is improved significantly. When addingthe modified sepiolite and ZnO to the PP/EPDM-g-MAH/IFRsimultaneously, the char residue is dense and homogeneous, and the chemical reactions among the sepiolite, ZnO and IFR promotes thecrosslinking charring effect of IFR at high temperature. The effect ofinterfacial properties controlled by modifying the surface properties of SPis studied, due to the poor compatibility between PPand SP. It is foundthat the LOI value of the system is increased from29to32, when SP ismodified by the silane.Under UV irradiation, TBSBPE produces Br which responses withPP and generate alkyl radicals, and ammonium polyphosphate (APP)decompose and liberate phosphoric acid, and further dehydrates to formpyrophosphate. So the photo-oxidation rate of PP containing TBSBPE orIFR is higher than PP. However, the photo-oxidation degradation of PP,TBSBPE and IFR is delayed after adding the composite light stabilizer.This is because the alkaline of hindered amine light stabilizer (HALS) isweak, and the antagonism with HBr which TBSBPE release is notobvious in the TBSBPE-flame retardant PP system. And in the IFR-flameretardant PP system, IFR doesn’t effect the light stability of HALS.The light stabilization of the PP/IFR with SP which delayphoto-oxidation degradation of PP and IFR in the initial stage of UVirradiation, is better than the PP/IFR system. However, SP plays the roleof light stabilization mainly in the late UV aging after adding thecomposite light stabilizer. |
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