以聚多巴胺包覆二氧化硅(PDA@SiO₂)、三氯氧磷(POCl₃)和4,4-二氨基二苯基甲烷(DDM)为原料,合成了阻燃剂修饰的聚多巴胺包覆二氧化硅(P/N-PDA@SiO₂),将其引入水性聚氨酯(WPPU),制得阻燃剂修饰聚多巴胺包覆二氧化硅/水性聚氨酯(P/N-PDA@SiO₂/WPPU)。通过扫描电镜、万能试验机、热失重、极限氧指数、垂直燃烧及锥形量热等测试了涂层的化学结构、断面形貌、力学性能、热稳定性、燃烧性能和阻燃机理。结果表明:加入P/N-PDA@SiO₂后,涂膜的力学性能出现先增加后降低的趋势,最大拉伸强度可达9.08MPa。涂层的热重分析表明,复合涂膜的残炭量高于纯WPPU涂膜。此外,复合涂膜的极限氧指数值随着P/N-PDA@SiO₂的添加而上升,阻燃等级达到V-0,热释放速率峰值、总热释放量、材料总升烟量分别降低了25.9%、13.5%、52.8%,表明了P/N-PDA@SiO₂对复合涂膜阻燃性能的稳定提升作用。

Using polydopamine-coated silica (PDA@SiO₂),phosphorus oxychloride (POCl₃) and 4,4-diaminodiphenylmethane (DDM) as raw materials,a flame retardant modified polydopamine-coated silica (P/N-PDA@SiO₂) was synthesized.P/N-PDA@SiO₂ was then introduced into waterborne polyurethane (WPPU) to prepare flame retardant modified polydopamine-coated silica/waterborne polyurethane (P/N-PDA@SiO₂/WPPU).The chemical structure,cross-section morphology,mechanical properties,thermal stability,combustion performance and flame retardant mechanism of the coatings were tested by scanning electron microscope,universal testing machine,thermal weight loss,limiting oxygen index,vertical combustion and cone calorimetry.The results showed that after adding P/N-PDA@SiO₂,the mechanical properties of the coating film first increased and then decreased,and the maximum tensile strength could reach 9.08MPa.The thermogravimetric analysis of the coatings demonstrated that the carbon residue of the composite coating film was higher than that of the pure WPPU coating film.In addition,the limiting oxygen index value of the composite coating film increased with the addition of P/N-PDA@SiO₂,and the flame retardant grade reached V-0,the peak heat release rate,the total heat release,the total smoke liters of the material decreased by 25.9%,13.5%,and 52.8%,respectively,which indicated that P/N-PDA@SiO₂ could stably improve the flame retardancy of the composite coating film.