Abstract

Microencapsulated ammonium polyphosphate (GMAAPP) and microencapsulated expanded graphite (PUEG) were prepared by in situ polymerization with glycidyl methacrylate (GMA) and polyurethane as the shell material respectively. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and thermogravimetry (TG) were used to characterize GMAAPP and PUEG. The results confirmed the successful fabrication of GMAAPP and PUEG. On this basis, a series of flame-retardant rigid polyurethane foam composites were prepared with GMAAPP and PUEG loading by the one-step water-blown method. The flame retardancy, mechanical properties, thermal insulation, and thermal stability of RPUF/GMAAPP30, RPUF/PUEG30, and RPUF/GMAAPP20/PUEG10 composites were investigated by limiting oxygen index (LOI), Underwriters Laboratories vertical burning test (UL-94), TG, thermal conduction and density test. The results showed that the thermal stability at the high temperature of RPUF composites can be improved by the addition of GMAAPP and PUEG. SEM test confirmed significantly enhanced compatibility between the microencapsulated flame retardant particles and RPUF matrix, which obviously improved the integrity of the cell structure. RPUF/GMAAPP30, RPUF/PUEG30 and RPUF/GMAAPP20/PUEG10 exhibited LOI of 22.3 vol%, 25.3 vol%, 24.6 vol% with all composites passed V-0 rating in UL-94 test. The physical performance test indicated that RPUF/GMAAPP20/PUEG10 exhibited thermal conductivity of 0.0395 W/m·K and compressive strength of 0.292 MPa, which possessed the best comprehensive physical performance. Char residue analysis suggested the combination of GMAAPP and PUEG increased graphitization degree and compactness of char residues for RPUF composites, thus effectively improving the fire safety of the composite.

摘要

分别以甲基丙烯酸缩水甘油酯（GMA）和聚氨酯为壳材料，通过原位聚合制备了微胶囊聚磷酸铵（GMAAPP）和微胶囊膨胀石墨（PUEG）。傅里叶变换红外光谱 (FTIR)、X 射线光电子能谱 (XPS)、扫描电子显微镜 (SEM) 和热重法 (TG) 用于表征 GMAAPP 和 PUEG。结果证实了GMAAPP和PUEG的成功制备。在此基础上，采用一步水吹法制备了GMAAPP和PUEG负载的一系列阻燃硬质聚氨酯泡沫复合材料。通过极限氧指数(LOI)研究了RPUF/GMAAPP30、RPUF/PUEG30和RPUF/GMAAPP20/PUEG10复合材料的阻燃性、力学性能、隔热性和热稳定性，美国保险商实验室垂直燃烧测试（UL-94）、TG、热传导和密度测试。结果表明，加入GMAAPP和PUEG可以提高RPUF复合材料的高温热稳定性。SEM测试证实微囊化阻燃颗粒与RPUF基体的相容性显着增强，明显提高了泡孔结构的完整性。RPUF/GMAAPP30、RPUF/PUEG30 和 RPUF/GMAAPP20/PUEG10 的 LOI 分别为 22.3 vol%、25.3 vol%、24.6 vol%，所有复合材料均通过 UL-94 测试中的 V-0 等级。物理性能测试表明，RPUF/GMAAPP20/PUEG10的导热系数为0.0395 W/m·K，抗压强度为0.292 MPa，综合物理性能最佳。