热塑性聚氨酯对膨胀型阻燃聚丙烯的增容作用

热塑性聚氨酯（TPU）含有氨基甲酸酯链段,该结构有利于受热成炭,提高阻燃性能,又可以通过超分子间力与膨胀型阻燃剂（IFR）作用,而TPU的软段与聚丙烯（PP）结构相似,因此可作为PP/IFR体系的增容剂.力学性能和阻燃性能测试表明,3%TPU的加入,使材料的拉伸和冲击性能分别提高了9.8%和16.6%,离火自熄时间由45s降低到25 s;在TPU添加量为4%时,材料的冲击性能提高显著,已经达到纯PP的水平.流变性能测试结果表明,在测试温度下,由于TPU软化点较低,而IFR中季戊四醇（PT）又处于熔化状态,加入TPU和IFR使粘度降低,但加入量增加到5%时,体系粘度增大,说明TPU对体系起到了增容作用.SEM微观形态分析表明,随TPU含量增大,IFR与PP界面作用力增强,断裂由发生在IFR与PP的界面,变为发生在底材内部,说明TPU对体系起到了增容的作用.事实证明TPU是PP/IFR共混体系有效的增容剂.

Compatibilization Effect of Thermoplastic Polyurethane on Intumescent Fire-retardant PP

Thermoplastic polyurethane (TPU) contains carbamate segments, which is favorable for the formation of char by heating and the increase of flame retardancy, and could act with intumescent fire-retardant (IFR) by supermoleculer force. The flexible segments of TPU are similar to those of PP, so that TPU could be used as compatibilizer for PP/IFR blend. The results of mechanical properties and fire retardancy tests showed with the addition of 3% TPU to the blend, the tensile strength and impact strength of the blend increased by 9.8 % and 16.6 % respectively; the extinguish time shortened from 45 s to 25 s. When the content of TPU in the blend was 4 %, the impact property of the blend increased significantly, came up to the level of that of pure PP. The results of rheological properties tests showed at the test temperature, due to the low soften point of TPU and the PT in melting matter, the apparent viscosity decreased with the addition of TPU and IFR, but when the content of TPU increased to 5 %, the viscosity of the blend increased, which showed TPU had compatibilization effect on PP/IFR blend. The results of SEM micromorphology analysis indicated with the increase of the content of TPU, the interfacial action between IFR and PP increased, and the fracture took place in matrix, not on the interface of PP/ IFR, implied that TPU improved the compatibility between PP and IFR, and TPU was an effective compatibilizer for PP/IFR blend.