聚氨酯／石墨烯纳米复合物的制备、力学及温度-电阻率行为研究

采用改进的hummers法，并以NaBH4还原制得还原石墨烯（RGO）．以蓖麻油（CO）和2，4-甲苯二异氰酸酯（2，4-TDI）为原料合成蓖麻油基聚氨酯预聚体．利用原位聚合法将聚氨酯预聚体与还原石墨烯反应（不完全还原），制得不同石墨烯含量的聚氨酯／石墨烯纳米复合物．采用x线衍射、傅里叶变换红外光谱、拉曼光谱、热重分析以及力学和热-电阻特性测试对复合物薄膜的结构和性能进行研究．实验结果显示聚氨酯／石墨烯复合物薄膜具有优良的热力学性能，特别是当石墨烯质量分数为1．5％时，聚氨酯／石墨烯纳米复合物出现正的电阻率-温度效应（PTC效应）．

Preparation,mechanics and resistivity-temperature behavior of polyurethane/graphene nanocomposites

Reduced graphene-oxide（RGO） was prepared by the improved hummers method and NaBH4 reduction. Castor oil-based polyurethane prepolymer was synthesized by using castor oil（CO） and 2, 4-toluene di-iso-cyanate （2, 4-TDI） as raw materials. Polyurethane/graphene （PU/RGO） nanocomposites were in situ synthesized using polyurethane prepolymer and different concentration of RGO. In addition, the structure and properties of nanocomposites films were investigated by XRD, FT-IR, Raman, TGA, mechanical analysis and thermal-electric resistance measurement, respectively. The results indicated that Polyurethane/RGO nanocomposites provided with good thermal stability, mechanics. Especially, PU/RGO indicated positive temperature-resistivity coefficient, when graphene was 1.5 % （weight rate） in nanocomposites.