以三(2-羟乙基)异氰尿酸酯(THEIC)、衣康酸酐(ITA)、9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)和甲基丙烯酸缩水甘油酯(GMA)为原料,合成了结构明确的含磷-氮丙烯酸树脂(TIDG),并将其添加到聚氨酯丙烯酸酯(PUA)体系中,经紫外光固化后制备得到含磷-氮阻燃元素的PUA涂层。通过万能试验机、热失重(TGA)、锥形量热(CONE)、扫描电镜(SEM)及拉曼等仪器测试了涂层的力学性能、热稳定性、燃烧性能和阻燃机理。结果表明,加入TIDG后,涂层的附着力、铅笔硬度和拉伸性能都得到了提升。从涂层的热重曲线看出,添加TIDG后PUA/DITG涂层的残炭量增大。此外,相较于纯PUA涂层,添加了40 wt% TIDG的PUA涂层的热释放速率峰值和总热释放量分别降低了35.2%和42.1%。扫描电镜和拉曼测试表明磷-氮协同效应能加速涂层形成致密膨胀结构的炭层。
An ultraviolet (UV) curing phosphorous-nitrogen contained flame retardant resin (TIDG) was first synthesized by reaction of tris (2-hydroxyethyl) isocyanurate (THEIC), itaconic anhydride (ITA), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and glycidyl methacrylate (GMA). The obtained TIDG was then mixed with polyurethane acrylate (PUA) resins and cured by UV light irradiation. Mechanical properties, thermal stability, combustion properties, and flame retardant mechanism were investigated using universal testing machine, thermogravimetric analyzer, cone calorimeter scanning electron microscope and Raman spectra, respectively. The results showed that the adhesion strength, tensile strength and pencil hardness of the PUA/DITG coating were all improved compared to pure PUA coating. The amount of carbon residue of PUA/DITG coating increased with the content increase of TIDG. In addition, compared with the pure PUA coating, the peak heat release rate and the total heat release of the PUA/40 wt% TIDG coating were reduced by 35.2% and 42.1%, respectively. Furthermore, the phosphorus-nitrogen synergistic flame retardant effect of PUA/DITG coating was demonstrated by scanning electron microscopy and Raman tests to accelerate the formation of dense and expand carbon layer.