Study On The Properties Of Rigid Polyurethane Foam With Expandable Graphite Particles As Flame Retardant

Rigid polyurethane foam(RPUF) is widely used in many fields, such as industries, daily lives and construction, etc. But the use of RPUF is limited for its flammability. Thus, researchers pay more attention to improve the flame retardant properties of RPUF.In this work, many experimental methods were used, such as horizontal and vertical burning test, limiting oxygen index test, scanning electron microscopy, mechanical measurement, dynamic mechanical analysis, thermogravimetric analysis. And three main works were studied. First, the dependence of flame retardant properties on density of EG filled RPUF was studied. Second, the properties and influencing mechanisms of hollow glass microsphere(HGM) and EG filled RPUF were investigated. Finally, the properties and influencing mechanisms of silicon whisker(WSi) and EG filled RPUF were studied. Through these experiments, we could obtain several concludes which are listed thereinafter.(1) The flame retardant properties of EG filled RPUF composites depend on their densities. With the density increasing, the flame retardant properties of theses composites get better.(2) HGM particles and WSi particles can not improve the flame retardant properties of EG/RPUF composites obviously. With the additives increasing, the linear burning rate of EG/RPUF composites can slightly fall, so the flame retardant properties can be improved slightly.(3)When HGM particles and WSi particles cooperate with EG particles to fill RPUF, the flame retardant properties of RPUF composites can be improved obviously. This point indicates that HGM particles and WSi particles have synergy effect with EG particles.(4)When HGM particles and WSi particles cooperate with EG particles to fill RPUF, the mechanical properties of RPUF composites can be improved obviously.(5) Thermogravimetric analysis reveals that the adding of EG, HGM, WSi can increase the residual weight of RPUF composites. But it can not improve the thermal stability of RPUF matrix essentially.(6) The adding of EG, HGM, WSi can increase the glass transition temperature of RPUF and wide the temperature range for damping.