微胶囊膨胀石墨对EPDM/PP阻燃性能影响的研究

Effect of Microencapsulated Expandable Graphite on the Flame Retardant Properties of EPDM/PP

摘要:

为了提高可膨胀石墨在聚合物中的阻燃效率及其与聚合物的界面相容性，含磷聚氨酯可作为可膨胀石墨的有效界面改性剂。以三羟甲基氧化磷和甲苯-2,4-二异氰酸酯为反应原料，采用溶剂法制备了含磷聚氨酯微胶囊膨胀石墨。利用红外光谱和扫描电镜表征含磷聚氨酯微胶囊膨胀石墨的结构。采用极限氧指数和UL-94垂直燃烧、热重分析及电子拉力机等表征手段，研究了含磷聚氨酯微胶囊膨胀石墨对EPDM/PP热塑性弹性体阻燃性能、热稳定性和力学性能的影响。实验结果表明：含磷聚氨酯成功包覆在可膨胀石墨表面形成微胶囊膨胀石墨，含磷聚氨酯微胶囊膨胀石墨能明显提高EPDM/PP的阻燃性能；当含磷聚氨酯微胶囊膨胀石墨的添加量为30%时，氧指数约达25%，UL-94垂直燃烧达到V-0等级，700 ℃时的残碳率约为20.4%；相比可膨胀石墨，添加30%的含磷聚氨酯微胶囊膨胀石墨后的EPDM/PP复合材料的最大热分解温度达450 ℃，提高了约8%。含磷聚氨酯微胶囊膨胀石墨的加入能有效降低阻燃剂对EPDM/PP热塑性弹性体的力学性能的破坏，添加了30%的含磷聚氨酯微胶囊膨胀石墨复合材料的综合性能最好。

Abstract:

In order to improve the flame retardant efficiency of expandable graphite in the polymer and its interface compatibility with the polymer， phosphorous polyurethane can be used as an effective interface modifier of expandable graphite. Phosphorous polyurethane microencapsulated expanded graphite was prepared by solvent method using tris（hydroxymethyl）phosphine oxide and toluene 2，4-diisocyanate as reaction materials. The structure of microencapsulated expanded graphite was characterized by infrared spectroscopy and scanning electron microscopy. The effects of phosphorous polyurethane microencapsulated expanded graphite on flame retardancy， thermal stability and mechanical property of EPDM/PP thermoplastic elastomers were studied by limiting oxygen index， UL-94 vertical combustion， thermogravimetric analysis and electronic tensile machine. The experimental results showed that phosphorus polyurethane was successfully coated on the surface of expandable graphite to form the microencapsulated expandable graphite， which could significantly improve the flame retardant of EPDM/PP. With addition of 30 wt.% of microencapsulated expandable graphite， the oxygen index reached around 25%， the vertical combustion of UL-94 reached V-0 grade， and the char residue rate was around 20.4% at 700 ℃. Compared with the expandable graphite， the maximum thermal decomposition temperature of EPDM/PP composite with 30 wt.% of microencapsulated expandable graphite was 450 ℃， which was increased by around 8%. The mechanical properties of EPDM/PP thermoplastic elastomer could be effectively reduced by adding microencapsulated expandable graphite. Comprehensive analysis of flame retardant and mechanical properties of composite materials showed that ， the composite materials could achieve the best performance when 30 wt.% of microencapsulated expandable graphite was added .