Research On Properties Of Flame Retardant Modified Polypropylene And Its Foaming Materials

Polypropylene?PP?is a general-purpose polymer material with excellent molding processability.Polypropylene foam material made of polypropylene can be widely used in interior parts of rail transportation such as automobiles.However,PP itself is a flammable material,and PP foaming material is more easily ignited,which greatly reduces the safety of its use and limits its application range.Therefore,it is necessary to modify the flame retardant of polypropylene to improve the flame retardant properties of polypropylene and its foaming materials.Adding a flame retardant to the polypropylene resin for blending modification is the most effective method to enhance the flame retardant performance.The polypropylene material of FL7540L was selected in the experiment.PP was modified by using intumescent flame retardant?IFR?and bromine flame retardant.The modification of different flame retardants was obtained by extrusion granulation.PP particles.The experimental results show that the addition of two types of flame retardants can significantly improve the flame retardancy of PP.The LOI of pure PP is 17.8,while the LOI value is increased to 29.2 when the IFR mass fraction is 30%,and the LOI value is increased to 27.9 when the mass fraction of the brominated flame retardant is 35%.The addition of two types of flame retardants will reduce the impact notch strength and tensile strength of the material.The brominated flame retardant has less influence on the mechanical properties of the material than the IFR.It can be observed by SEM that the IFR is dispersed in the polypropylene.Poor sex.In the experiment,the reactor foaming method was used,and the PP particles were foamed by using inexpensive and environmentally friendly CO₂ as a physical foaming agent.The effects of flame retardant addition,saturation temperature and saturation pressure on the foaming behavior of PP were studied.The experimental results show that the expansion ratio of polymer will increase first and then decrease with the increase of flame retardant.For the intumescent flame-retardant PP foaming material,the expansion ratio reaches a peak of 10.8 when the IFR mass fraction is 10%;when the IFR mass fraction reaches 30%,the flame retardant particles are unevenly dispersed in the polypropylene matrix,and the agglomeration phenomenon is serious.It has begun to adversely affect the foaming of polypropylene.In order to meet the requirements for the rate of magnification and flame retardancy of the foamed material,it is more appropriate to control the mass fraction of the IFR at 25%and 30%.Under the same conditions,the magnification of the foamed material increases with the increase of the saturation temperature and the saturation pressure.In this paper,the IFR foaming material is made into a molded product by steam forming technology,and compared with the mechanical properties and flame retardant properties of the sample before foaming.The experimental results show that the mechanical properties of IFR flame retardant foaming materials compared to pure PP foaming materials are reduced.For the foamed material with an IFR mass fraction of 30%,the combustion performance can be measured by the horizontal combustion method of the foam material,which can reach HF-1 grade,and the foamed product can self-extinguish within two seconds from the fire.