Synthesis And Flame Retarded Properties Study Of Polymeric Phosphorus Amide Flame Retardant

Majority of flame retardants used in materials are consisted of low-molecular-weight chemicals.Once those chemicals escaped from the manufacturing process or leaching out of the product over years,they began to have environmental impact and do harm to health.With the advantage of environmental profile,polymeric flame retardants had been widely researched by manufacturers and researchers.In this paper,two novel polymeric flame retardant with spiro and phosphoramide structure including poly(4,4-diaminodiphenylsulfone spirocyclic pentaerythritol bisphosphonate)(PCS)and poly(4,4-diaminodiphenyl methane spirocyclic pentaerythritol bisphosphonate)(PCM)were successfully synthesized in acetonitrile solvent by the solutionpolycondensation reaction between 4,4'-diaminodiphenylsulfone(DDS),4,4'-diaminodiphenyl methane(DDM)and spirocyclic pentaerythritol bisphosphorate disphosphoryl chloride(SPDPC).The two products were well characterized and analysed by fourier transform infrared spectroscopy(FT-IR),nuclear magnetic resonance(NMR),gel permeation chromatography(GPC),thermogravimetric analysis(TGA),differential scanning calorimetry(DSC)and scanning electron microscope(SEM).Feasibility research was explored to study whether these novel flame retardants had efficiency on resins.Flame retardant mechanism was also studied by a variety of testing methods.Finally these novel flame retardants was verified to be high efficient,environmental friendly and suitable for large-scale industrialization.The main research work is as follows:(1)A novel self-intumescent flame retardant,poly(4,4-diaminodiphenylsulfone spirocyclic pentaerythritol bisphosphonate)(PCS),was synthesized through solution polycondensation by DDS and SPDPC.The product was characterized by FTIR,NMR and TG.When 20% PCS was added,LOI increased to 31.2,UL-94 test reached V-0 level.Their combustion performance and thermal properties were evaluated by CONE,TG and TG-FTIR.The morphology and chemical structure of residual chars were observed by SEM and FTIR.The results illustrated that PCS can greatly increase residual chars and delay the decomposition rate of matrix.(2)A novel self-intumescent flame retardant,poly(4,4-diaminodiphenyl methane spirocyclic pentaerythritol bisphosphonate)(PCM),was synthesized through solution polycondensation by DDM and SPDPC.The product was characterized by FTIR,NMR andTG.When 20% PCM was added,LOI increased to 31.8,UL-94 test reached V-0 level.Their combustion performance and thermal properties were evaluated by CONE,TG and TG-FTIR.The morphology and chemical structure of residual chars were observed by SEM and FTIR.The results illustrated that PCM can greatly increase residual chars and delay the decomposition rate of matrix.(3)The PCS and PCM were respectively applied to EP with APP.We could reach that the addition of APP could not only improve the phosphorus content of flame retardant system,effectively reduce the dosage of flame retardant agent,also could make the heat release process becomes relatively smooth,so that the heat gradually released in a longer time range,which could reduce the possibility of fire caused by rapid release heat.Therefore,PCS and PCM both had good synergistic effect on flame retardant epoxy resin with APP.The contrastive study between PCS,PCM and small molecules flame retardant SPDPC was conducted and the results showed that polymer PCM and PCS had obvious advantages over small molecule flame retardant SPDPC on the flame retardant of epoxy resin,and could solve the moving out problem of small molecule in curing.The flame retardant effect of PCS and PCM flame retardant on EP were compared and analyzed,and the PCM was better than that of PCS.