Preparation And Properties Of Heat Resistant And Flame Retardant Polyurethane Rigid Foam

Rigid polyurethane foam materials owes the characteristics of low density,high specific strength, good wear resistance, the lowest coefficient of thermal conductivity,excellent shock absorption performance, ect. Which makes RPUF a widely used material in the area of building insulation. Nevertheless, its major defects including flammability while burning and poor heat resistance thus restricting its applications in revalent areas. So it’s high time to develop a rute to enhance the heat resistance and flame retardant properties of the RPUF.In this paper, from the view of molecular structure design, a novel heat resistant epoxy resin which contains a bisphenyl monomer4-(4-hydroxyphenyl)-1-phthalazinone (DHPZ) was synthesized. The modified rigid polyurethane foam (DEP-RPUF) was successfully prepared using the epoxy resin D-EP as a modification agent and certain addictives in the entire water foaming system. The effect of the D-EP content on tensile properties, compressive strength, dimensional stability, density, Limited Oxygen Index (LOI) were studied systemly,and the thermal properties and morphological structure were investigated with the help of TGA and SEM respectively. It was noticed that the DEP-RPUF containing10%or more D-EP showed the volume change within1percent after exposed in150℃and-30℃for48h, the tempreature of5%weight loss is above257℃,the residue at800℃is above22.5%.The flame retardant polyurethane foam was prepared using halogen free flame retardants Microencapsulated Red Phosphorus(MRP) in a entire water foaming system. The effect of the MRP content on certain properties of the rigid foam was examed systematically. The Limited Oxygen Index of the MRP modified RPUF reached to29with the MRP adding amount to25%. In order to further improve the flame retardancy, a novel composite flame retardant (CoMRP) was prepared using (MRP). The RPUF was prepared using the CoMRP. It’s found that the Limited Oxygen Index(LOI) of the CoMRP-RPUF is greater than30with the CoMRP adding amount28%or more.The CoMRP shows excellent flame retardancy and a little loss of mechanical properties.