Study On Flame Retardant Thermoplastic Polyurethane Elastomer Based On Silica And Phosphorus

In recent years,halogen-free flame retardant is a key research focuses in the field of flame retardant.Among them,silicon flame retardant POSS and nano-flame retardant research is the hot spot in the field.In this paper,the new nano-flame retardant OPS and DOPO-MMT were applied to the polyurethane elastomer(TPU)to make composite materials,and with other phosphorus-containing flame retardants(APP,ADP,DOPO)and inorganic flame retardants(MMT)The effects of new flame retardants on the flame retardancy of polyurethane elastomers were studied,and the mechanism of flame retardancy was analyzed.This paper is divided into the following three parts.First,OPS was added to the polyurethane elastomer by melt blending,and a new type of polyurethane elastomer composite was obtained.The flame retardancy of the samples was investigated by means of limiting oxygen index,vertical combustion,cone calorimeter and scanning electron microscopy.It was found that OPS increased the strength of polyurethane melt,significantly inhibited the formation of combustion droplets.The heat release rate was reduced,and the weight loss test showed that the residual carbon content of the composite was improved by OPS.Based on the above test results,it was determined that the optimum amount of OPS flame retardant polyurethane elastomer was 15wt%.Then,the OPS was mixed with the phosphorus-containing flame retardants APP and ADP,and the synergistic flame-retardant effect of silicon and phosphorus in the polyurethane elastomer was investigated by LOI,vertical combustion(UL-94),cone calorimeter(CONE),X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM)They were used to simulate the combustion of several flame-retardant systems Performance and carbon layer structure.It was found that the flame retardant properties and thermal properties of TPU were significantly improved after the combination of OPS and phosphorus and flame retardant APP and ADP,and the synergistic flame retardant effect of APP was significantly better than that of ADP.TPU/10%OPS/APP is the best overall performance,the peak heat release test can be reduced from 1339kW/m~2 to 489kW/m~2,a decrease of 63.5%.Total smoke release from 3425m~2/m~2 down to 1884m~2/m~2,and the decline has reached 45.0%;flame retardant TPU cone test of the carbon layer can be seen under the SEM more dense,hard and porous order of the carbon layer.Finally,the new DOPO-MMT nanocomposite flame retardant polyurethane elastomer was selected and its flame retardancy and flame retardant mechanism were studied.The DOPO-MMT nanocomposites prepared by our research group were added to the polyurethane elastomer to obtain a new type of polyurethane elastomer composite.And its flame retardant effect and separately add DOPO,MMT and DOPO and MMT physical mixture of the effect of comparison.The results show that the flame retardant effect of DOPO-MMT flame retardant is better than that of DOPO,MMT and physically mixed DOPO and MMT flame retardants,because DOPO-MMT achieves nanometer level in polyurethane.The gas phase flame retardation of the DOPO and the coagulation phase flame retardation of the MMT is complementary to each other,and the flame is suppressed,so that the UL-94 vertical combustion of the polyurethane composite material reaches the V-2 level.And the lowest heat release in the cone calorimetry.The material obtained a good flame retardant effect.