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影响的研究

Study on Effect of Flame Retardant of EPDM/PP Thermoplastic Elastomer by Phosphorous Polyurethane Microencapsulated Expandable Graphite

摘要:

为了提高可膨胀石墨（EG）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EG的有效界面改性剂，以三羟甲基氧化磷（THPO）和甲苯-2,4-二异氰酸酯（TDI）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（MEG）．利用红外光谱（FTIR）和扫描电镜（SEM-EDS）表征MEG的结构．采用极限氧指数（LOI）和UL-94垂直燃烧、热重分析（TG）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（MEG）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EG表面形成微胶囊后的膨胀石墨（MEG），MEG能明显提高EPDM/PP的阻燃性能；当MEG的添加量为30%时，氧指数达到25%，UL-94垂直燃烧达到V-0等级，700 ℃时的残碳率为20.4%；相比EG，添加30%的MEG后的EPDM/PP复合材料的最大热分解温度达450 ℃，提高了8%．MEG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．综合分析复合材料的阻燃性能及力学性能，添加30%的MEG，复合材料综合性能最好。

Abstract:

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