可膨胀石墨阻燃半硬质聚氨酯缓冲泡沫研究

摘要

半硬质聚氨酯泡沫（ SPF）材料由于突出的缓冲性能而具有广泛的应用潜力。由于SPF密度低且开孔率较高，遇到火源时极易发生燃烧，存在安全隐患，严重限制了其在航天等特殊领域的应用。可膨胀石墨（ EG）是一种典型的物理膨胀型无卤阻燃剂，可以有效地改善材料的阻燃性能。为研究 EG 粒径和填充量对 SPF 阻燃性能的影响，选用三种大跨度粒径 EG （70μm，430μm，960μm），采用一步法制备了不同EG填充量的复合泡沫，对比了三种粒径EG在不同填充量（5 wt．％，15 wt．％，25 wt．％，50 wt．％）下对半硬质聚氨酯泡沫各项性能的影响。结果表明：EG能明显改善半硬质聚氨酯泡沫的阻燃性能，且粒径是EG阻燃的关键因素，大粒径、高填充量的EG能有效提高泡沫材料的阻燃性，在50 wt．％时，EG-960μm填充泡沫的氧指数高达31％。小粒径的EG-70μm不仅对泡沫的阻燃性无改善作用，甚至能促进泡沫的燃烧。同时，小粒径的EG-70μm能明显提高泡沫原料的粘度，影响泡沫的成型过程。%Semi-rigid polyurethane foam ( SPF) has a wide range of potential applications due to its outstanding cushioning performance.However, SPF is highly ammable owing to its low density and open-cell structure, which limits its greater use in many fields, especially in the aerospace and other special areas.Expandable graphite (EG) is a typical halogen-free intumescent flame retardant, which can effectively improve the flame retardant properties of the material.In this paper, three kinds of large-span size of EG (70μm, 430μm, 960μm) were used to modify SPF with different loading a-mounts(5 wt%., 15 wt%., 25 wt%., 50 wt%.).The effects of EG on SPF properties were investigated. The results showed that EG can significantly improve the flame retardancy of SPFs.The particle size of EG is crucial to the flame retardancy of EG filled SPF.Larger particle size and higher loading frac-tions of EG can significantly improve the flame retardancy of SPFs.The LOI of EG-960μm/SPF with 50 wt%. EG reached as high as 31%.EG-70μm exhibited no improvement on the flame retardancy of SPF, but accelerated the combustion process.What’ s more, EG-70μm can significantly increase the viscosity of the foam reaction mixture and impact the process of foam molding.