The Research On The Preparation And Properties Of Intumescent Flame Retardant Polypropylene Material

In this paper, intumescent flame retardant polypropylene (PP) material wasstudied. The acid agent and the carbon agent of intumescent flame retardant systemwere studied by LOI, UL-94vertical burning tests and CONE test, as well as the effectof surface treatment on PP flame retardant properties. At the same time, the mechanicalproperties and processing properties were also studied. In order to improve the waterresistance properties and dispersion of phosphorus-nitrogen IFR, the ammoniumpolyphosphate was coated by melamine resin and the IFR was made into microcapsule.To further improve the flame retardant properties of IFR, the IFR was made intomicrocapsule with the triazine compouds as carbon agent. Then the effect of triazineIFR on flame retardant properties was studied. The flame retardant mechanism of IFRwas studied by using TGA, stereoscopic microscope and DSC.1. Under same content, the LOI of PP/IFR-4flame retardant system was smallerthan that of PP/IFR-3flame retardant system. When added IFR-4, the initial thermaldecomposition temperature of PP decreased, on the contrary, the temperature of themaximum thermal decomposition rate and the amount of carbon residue increased.After adding IFR-4, the HRR, MLR and EHC of PP decreased significantly. Theintumescent flame retardant property of IFR was obvious, which could be proved bythe carbon layer of PP/IFR-4combustion residue.2. The LOI and vertical burning level of PP/IFR-1and PP/IFR-2flame retardantsystem were higher that of PP/BFR flame retardant system, under the same content.The smoke density of PP decreased after adding IFR-2and IFR-2. Under the samecontent, the mechanical properties of PP/BFR system were better than that of PP/IFR-1and PP/IFR-2system. With the increase of the content of IFR-2, the initialdecomposition temperature of PP decreased gradually, the maximum decomposition rate temperature and the amount of carbon residue increased. When the content ofIFR-2was40phr, the HRR, MLR and EHC of PP decreased significantly. The incarbonization effect of triazine IFR was obvious which could be proved by the densecarbon layer of PP/IFR-2combustion residue.3. PP flame retardant masterbatch had no influence on the flame retardantproperties. What’s more, the dispersion of flame retardants in PP matrix and themechanical properties of PP were improved. With the increase of content of PTFE, thetensile strength and impact strength of PP increased after first decreased, and thebending strength increased gradually. When adding0.2phr PTFE, the dripping of PPduring burning was inhibited, and the UL-94vertical burning test could reach V-0level.With the increase of content of EG, the tensile strength and impact strength decreasedafter first increased, and the bending strength increased gradually. At the same time,the LO of PP increased. When the content of EG was40phr, PP could reach V-0levelof UL-94vertical burning test. From the stereoscopic microscope, it could be seen thatthere was a continuous carbon layer on the residual of PP/EG flame retardant system.There were a lot of bubbles on the carbon layer, the density of the carbon layer wasquiet high, and was difficult to break. After intumescent, the graphite changed fromscaly to sparse worm-like, and became a good adiabatic layer. The trend of changes inmechanical properties of PP during immersion test was similar. After immersionexperiment, the mechanical properties and flame retardant properties decreased, butthe extent of the decline of flame retardant was little. The mechanical properties of lowmelt index flame retardant PP was better than that of high melt index flame retardantPP. On the contrary, the flame retardant properties of high melt index flame retardantPP was better than that of low melt index flame retardant PP.