Abstract: Rigid polyurethane foam has low density, low thermal conductivity and excellent thermal insulation properties, but its heat resistance is poor which needs to be improved to meet the application requirements. In this paper, the ceramicizable RPUF modified polyurethane foam composite was prepared by using hard polyurethane foam (RPUF) as matrix, hydroxyl silicone oil (PDMS) as modified additive, low melting point glass powder, talc powder and kaolin as ceramicable filler. And, the effects of kaolin on the compressive strength, thermal conductivity and ablative properties at high temperature of the ceramicizable PDMS modified polyurethane foam composites were studied. The results show that with the increase of kaolin content, the density of the material increases, the thermal conductivity increases, and the compressive strength increases. The SEM results show that a ceramic continuous phase structure is formed on the surface of the material after ablation at 800 ℃. XRD analysis indicates that the newly formed ceramic phase was α-quartz and orthorhombic manganese. Therefore, the addition of the inorganic filler effectively improves the heat resistance of the rigid polyurethane foam.

Key words: modified polyurethane, polyurethane foam, PDMS, ceramicizable, composite