Design And Performance Study Of Flame Retardant EPDM-based Rubber-Plastic Composites With Low Smoke And Low Toxicity

Ethylene Propylene Diene Monomer(EPDM)rubber-plastic composites are widely used in public construction,transportation facilities,electrical and packaging materials because of their excellent mechanical properties,processing properties and comprehensive properties(heat,light,ozone and chemical resistance).However,the LOI value of EPDM rubber-plastic composite material is only 20%,which means easy to burn.At the same time,EPDM and its rubber-plastic-composite materials will release a large amount of smoke and toxic gases during combustion.Therefore,the study of low-smoke,low-toxic and high-efficiency flame-retardant EPDM rubber-plastic composite materials is significant phenomenon.Herein,in our work,zinc-containing smoke suppressing vulcanizing agent,phosphorus-containing silane coupling agent with different structures,SnS2 with lamellar structure,and core-shell flame retardants with catalytic properties were designed and synthesized to form low-smoke,low-toxic and flame retardant rubber-plastic composites.The main research work is as follows:1.Zinc hydroxystannate(ZHS)and hexagonal zinc borate(ZB)were synthesized and added to EPDM/EVA rubber-plastic composites with different vulcanization systems to replace zinc oxide as vulcanization activator.By studying the effects of various vulcanization systems on the vulcanization properties,mechanical properties and flame retardancy of rubber,the suitable vulcanization system was determined choosed,and the effect of zinc-containing smoke suppression units in different vulcanization modes was studied.UL-94 and LOI tests have shown that ZB and magnesium hydroxide synergistic flame retardant systems enable EPDM/EVA to pass the UL-94 V-0 rating with an oxygen index of up to 33.5%.The cone calorimetry test shows that the sulfur-containing vulcanization system has a lower PHRR,and the addition of ZB can effectively reduce the PHRR and increase the safety of the material.Analysis of the pyrolysis process of the material by TG-IR revealed that the flammable components such as hydrocarbons were effectively reduced during the cracking process,which means lower fire risk.The SSTF smoke toxicity test shows that the introduction of both ZHS and ZB significantly reduced the release of CO.The data show that the zinc-containing smoke suppression unit can replace zinc oxide as an activator,so as to improve the flame retardant performance and ensure the normal progress of vulcanization.2.Meso porous hydroxystannate coated magnesium hydroxide flame retardant(MDH@mFeOHS)was prepared by ion-driven assembly.The combustion test shows that MDH@mFeOHS can greatly improve the flame retardant performance of the rubber-plastic material,and found that when 40%wt of MDH@mFeOHS was added,EPDM/EVA rubber composite can reach UL-94 V-0 level,and the LOI is as high as 32.0%.The PHRR can be reduced by more than 40%;the SSTF test shows that the impurity component of the EPDM/EVA material added by MDH@mFeOHS is effectively reduced.This is because the cross-linking point of the vulcanized rubber is introduced into the core-shell structure.The surface of the fuel improves the dispersion of the flame retardant and improves the flame retardant properties.3.Two phosphorus-containing silane coupling agents DOPO-VTS and PEPA-IPTS are designed and synthesized to improve the dispersion of AHP in rubber-plastic materials;The MnHS is synthesized to act as sygergist with AHP/PEPA-IPTS flame retardant EPDM/EVA rubbe-plastic materials.The test results show that both phosphorus-containing silanes can effectively improve the interfacial compatibility and mechanical properties of AHP rubber-plastic materials.PEPA-IPTS also enhances the flame retardant efficiency of AHP.When 90 parts of AHP and 10 parts of PEPA-IPTS are added to 150 parts(EPDM/EVA=2/1)of rubber-plastic materials,the composite can reach UL-94 V-05 the LOI value reaches 31.5%.In addition,the PHRR of the EE/AHP/PEPA-IPTS is reduced by about 20.0%after the addition of 5 parts of MnHS in place of the flame retardant.4.The layered SnS2 material is synth esized by hydrothermal method,and the flame retardant EPDM/PP rubber composite is compounded with APP and PER.DSC test results show that the introduction of SnS2 can effectively reduce the glass transition temperature of EPDM/PP rubber-plastic composites;in 100 parts of EPDM/PP rubber-plastic composites,when adding 4 parts of SnS2,39 parts of APP and 13 parts of PER,vertical combustion passed the V-0 level and the LOI value is also as high as 29.5%;the microcalorimeter(MCC)and the cone calorimetry(CCT)showed that the heat release of the material after the addition of SnS2 was significantly reduced;the flammable gas components such as hydrogen compounds are significantly reduced;the addition of SnS2 significantly improves the fire safety of EPDM/PP rubber composites.5.Zinc and tin-doped ammonium polyphosphate(ZSAPP)is synthesized by ion-driven method.The structure is characterized by SEM,and the formation of doped structure was proved.ZSIFR(ZSAPP/PER=3/1)can effectively improve the flame retardant performance of EPDM/PP,and can pass the V-0 level,compared with EPDM/PP/IFR(APP/PER=3/1),its LOI value increased by about 2.5%.Cone calorimeter testing show that the PHRR of EPDM/PP/ZSIFR is reduced by about 25%compared to EPDM/PP/IFR.The SSTF test results show that ZSIFR effectively reduces the toxic gases such as CO produced by EPDM/PP combustion.