【摘要】 以聚磷酸铵(APP)为主要阻燃剂,复配可膨胀石墨(EG)和膨润土作为阻燃剂和改性剂,制备了完全无机且无卤阻燃剂改性的硬质聚氨酯泡沫(RPUF)。在固定无机阻燃剂及改性剂总量的条件下,研究了膨润土和EG用量及比例对RPUF的热稳定性、阻燃性能、力学性能、泡孔结构等的影响。结果表明,随膨润土或EG含量的增大,泡沫的压缩强度先增大后减小,二者含量分别为10%和5%时压缩强度最大。EG对泡沫阻燃性能的提高有显著影响,但同时也会使泡孔孔径增大;而膨润土作为泡沫成核剂能明显减小孔径。通过热重分析表明膨润土和EG的加入能明显增强泡沫的热稳定性。当APP为泡沫总质量的15%,膨润土为5%,EG为5%时,可以制得阻燃性能、力学性能和泡沫孔径较佳平衡的阻燃泡沫材料。在该条件下,泡沫的压缩强度为0.42 MPa,泡沫平均孔径为434μm,LOI值达到29%。更多还原

【Abstract】 Rigid polyurethane foams modified by complete inorganic halogen-free flame retardants were prepared by using ammonium polyphosphate(APP) as main flame retardant, expandable graphite(EG) and bentonite as flame retardant and filler, respectively. Under the condition of fixing the amount of inorganic flame retardants and filler, the effects of the amount and ratio of bentonite and EG on the mechanical property, flame retardancy, cell structure, and thermal stability of the foams were evaluated. The results show that, with increasing the content of bentonite or EG, the compression strength of the foams increases at first and then decreases. The maximal compression strength can be obtained when the contents of bentonite and EG are 10% and 5%, respectively. The limiting oxygen index(LOI) values of the PU foams show good improvement of flame retardancy by adding EG, however the cell diameter of the foams will be increased at the same time. The bentonite as a nucleating agent can significantly reduce the cell diameter. The thermogravimetric analysis(TGA) illustrates that the thermal stability of foams containing bentonite or EG is significantly enhanced. The best balance among the flame retardancy, mechanical properties and the pore size can be achieved for the polyurethane foams prepared with 15% APP, 5% bentonite and 5% EG. Under the optimum condition, the compressive strength of the foams is 0.42 MPa, cell diameter is about 434 μm and LOI value is about 29%.更多还原