纳米SiO_2和发泡剂对聚氨酯防火涂料阻燃性能的影响

Effect of nano-SiO_2 and foaming agents on flame retardancy of polyurethane flame-retardant coating

近几年来我国火灾的严重性已使木材阻燃成为一项紧迫任务。为了提高马尾松胶合板的阻燃性能,以聚氨酯为对象,采用HRR3热释放率系统、HC-2氧指数测定仪等测定了涂覆膨胀型纳米聚氨酯防火涂料的马尾松胶合板的燃烧热释放率和氧指数,分析了纳米SiO2以及各种发泡剂对聚氨酯防火涂料阻燃性能的影响,并分析它们的阻燃机理。结果表明,在聚氨酯防火涂料中加入纳米SiO2,可使涂覆的胶合板燃烧失重和炭化体积明显降低,有效地提高阻燃性能,纳米SiO2用量以3%为宜。加入发泡剂可进一步提高涂料的阻燃效果和氧指数值。复合发泡剂比单一发泡剂效果好。在8种试验方案中,用尿素-双氰胺按1∶3的质量比组成的复合发泡剂阻燃效果最优,在HRR3热释放率系统测试中,涂覆的胶合板着火燃烧时间最长(69s),达最高热释放率时间最短(130s),热释放率峰值最低(53.45kW/m2),氧指数值最高(55)。

The present paper has been given the study of ways to improve the flame-retardant properties of Pinus masoniana plywood with the purpose to protect its users from life casualty and material loss. In doing so, we have made careful experiments with the flame- retardant properties of Heat Release Rate （HRR） and the oxygen index of the wood by using HRR3 （Heat Release Rate） system equip- ment and HC-2 oxygen index equipment. The Pinus maoniana plywood was treated by using polyurethane resin as a testing item with different amounts of nano-SiO2 polyurethane flame-retardant coatings, which are respectively added by kinds of blister agents （singleness blister agents carbamide and dicyandiumidy, and compound blister agent carbamide-dicyandiumidy with different proportions）, In addition, we have also analyzed the flame-retardant mechanism of the intumescent polyurethane flame-retardant coating with the purpose to produce a kind of high quality intumescent polyurethane flame-retardant coating and develop a wooden material flame-retardant technology. The results of our study have shown that, when the polyurethane flame-retardant coatings were mixed with different amounts of nano- SiO2, the burning weight loss and burning volume of residual char of the plywood can significantly reduced with its flame-retardant properties obviously increased. Its optimal proportions of nano-SiO2 amount prove to be 3 %. On the condition that the polyurethane flame-retardant coatings mixed with blister agents, the flame-retardant properties and the oxygen inddx of the plywood can be further increased. Moreover, the compound blister agent proves better than singleness one. And, finally, our tests prove that the best flame-retardant properties would appear when the best formula for compound blister agent： m （carbamide） ： m （dicyandiumidy） = 1：3 among the eight projects in our HRR3 study. The time that the projects begin to ignite has been proved the longest （69 s）, while the time the projects reach the highest HRR3 is the shortest （130 s）, with its peak being lowest （53.45 kW/m^2）. However, the amount that projects reach the oxygen index value proves the highest （55）.