中文摘要：

采用高速混合破碎机对可膨胀石墨（EG）进行处理，制得不同粒径的EG。考察了不同粒径EG填充的硬质聚氨酯泡沫塑料（RPUF）的微观形态，研究了EG对于RPUF燃烧行为的影响。结果表明：EG的粒径越小，其在聚氨酯体系中的分散就越困难；20％未经处理的EG粒子（EG0）填充的RPUF氧指数为39．5％，比未填充的RPUF氧指数提高了近一倍，而经过13min破碎的EG粒子（EG13）其氧指数仅为23．5％，与纯RPUF的氧指数在同一水平；水平垂直燃烧结果可进一步验证氧指数结果，当EGO填充量超过10％时，RPUF燃烧已经达到了V-0级，而RPUF／EG13因其阻燃性能较差只能用水平燃烧分级。由此可见，EGO可有效提高RPUF的阻燃性能，而EG13对RPUF的燃烧性能几乎没有影响；研究同时提出了不同粒径EG无卤阻燃高密度硬质聚氨酯泡沫塑料的阻燃机理。

英文摘要：

The effect of particle size of expandable graphite （EG） on the fire-retardancy of high density rigid polyurethane foam （RPUF） （0.45 g/cm3） was studied. The property of original EG （EGO） was compared with its smashing product （EG13）, which was obtained through pulverizing EGO in an ultra high speed mixer for 13 min. It is shown that the finer the particles, the more difficult to be dispersed and the poorer the fire-retardancy. At a content of 20 %, EGO may achieve an oxygen index of 39.5 %, while EG13 showed no improvement based on neat RPUF, 23.5 %. Different fire-retardant theories of rigid polyurethane foam filled by EG with different particle size, were also provided.