水性聚氨酯阻燃纳米复合材料的Click反应制备及性能

Preparation and Properties of Flame Retardant Waterborne Polyurethane Nanocomposites via Click Reaction

以4,4'-二羟甲基-1,4-庚二炔功能单体作为扩链剂制备了端炔基功能化聚氨酯,与叠氮基改性纳米蒙脱土(MMT-N3)、纳米氢氧化铝(ATH-N3)和纳米氢氧化镁(MH-N3)通过Click反应制备了水性聚氨酯(WPU)阻燃纳米复合材料.采用红外光谱(FTIR)、核磁氢谱(1H NMR)和扫描电子显微镜(SEM)对WPU阻燃纳米复合材料的结构进行了表征,对比研究了纳米阻燃剂配比和制备方法对WPU阻燃纳米复合材料的氧指数、动态燃烧行为和热稳定性的影响.阻燃性能研究结果表明,当MMT-N3,MH-N3和ATH-N3的质量分数分别为7%,2%和1%时,采用Click反应制备的复合材料的氧指数比纯WPU高7%,点燃时间从10 s延长到29 s,峰值热释放速率和烟释放速率分别降低了41%和42%.热失重分析结果表明,当MMT-N3质量分数为10%时,与WPU相比,采用Click反应制备的MMT/WPU复合材料在热失重50%时的温度提高了21℃.复合材料断面和燃烧后残渣的SEM分析证明在聚合物基体中Click反应是分散纳米材料的一种有效方法.

Polyurethane bearing the alkyne functions as pendant groups was synthesized via functional monomer 2,2-di（ prop-2-ynyl） propane-1,3-dio as chain extender. Flame retardant waterborne polyurethane（ WPU） nanocomposites were prepared by the Click reaction between alkyne-functionalized PU and azidomodified nano-montmorillonite（ MMT）,nano-aluminum hydroxide（ ATH） and magnesium hydroxide（ MH）.The structures of the flame retardant WPU nanocomposites were characterized by Fourier transform Infrared spectrometer（ FTIR）,proton nuclear magnetic resonance spectroscopy（1H NMR） and scanning electron microscopy（ SEM）. The influence of the ratio of nano flame retardants and preparation methods on limit oxygen index,dynamic combustion performance and thermal degradation behavior of the WPU nanocomposites were studied by the comparative study. The findings on flame resistance study indicated that when the mass fractions of MMT-N3,MH-N3 and ATH-N3 were 7%,2% and 1%,respectively,the oxygen index of the composites prepared by Click reaction was 7% higher than that of pure WPU,time to ignition was lengthened from 10 s to 29 s,and the peak heat release rate and smoke release rate were reduced by 41% and 42%,respectively. TGA results showed that when the mass fraction of MMT-N3 of 10%,the temperature at 50%mass loss of MMT/WPU composites prepared by Click reaction increased 21 ℃ compared with the WPU. SEM analysis of the composite section and combustion residue showed that Click reaction is an effective method to disperse nanomaterials in polymer matrices.