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以多壁碳纳米管(MWNTs)为原料,采用不同改性方法制得了羧化碳纳米管(MWNTs-COOH)、共价功能化碳纳米管(MWNTs-NH_2)、非共价功能化碳纳米管(MWNTs-PPA)和混杂功能化碳纳米管(MWNTs-COOH-PPA),将这4种改性碳纳米管按不同质量分数分别加入聚氨酯(PU)中制备了复合材料。使用万能材料试验机和热失重分析仪测试了复合材料的力学和热学性能,研究了碳纳米管对复合材料性能的影响。结果表明:通过在碳纳米管表面接枝少量的共价官能团防止非共价包覆的剥离,混杂功能化方法既能够改善碳纳米管在基体中的分散性,又能够保持其与基体界面间结合力,复合材料增强效果最明显。耐热性良好的碳纳米管的添加提高了PU基体的热分解温度,提高程度由于其功能化方式的不同而稍有差别。MWNTs-COOH-PPA/PU复合材料的力学性能最优,当碳纳米管含量(质量分数,下同)为0.3%时,其拉伸强度与纯PU相比提高104%,其热分解温度与MWNTs-COOH/PU相当,优于纯PU,但低于MWNT8-NH_2/PU和MWNTs-PPA/PU。
Multiwalled carbon nanotubes (MWNTs) were used as raw materials to prepare carbon nanotubes (MWNTs-COOH), covalently functionalized carbon nanotubes (MWNTs-NH_2), non-covalently functionalized carbon nanocrystals (MWNTs-COOH-PPA) and MWNTs-COOH-PPA. The four kinds of modified carbon nanotubes (MWNTs-COOH-PPA) were respectively added into polyurethane (PU) according to different mass fraction to prepare a composite material. The mechanical and thermal properties of the composites were tested using a universal testing machine and a thermogravimetric analyzer. The effects of carbon nanotubes on the properties of the composites were investigated. The results show that the hybrid functionalization method can not only improve the dispersibility of carbon nanotubes in the matrix, but also maintain the interface between the matrix and the matrix by grafting a small amount of covalent functional groups on the surface of the carbon nanotubes to prevent the non-covalent coating from peeling off Combination, the most obvious enhancement of composite materials. The addition of carbon nanotubes with good heat resistance improves the thermal decomposition temperature of the PU matrix, with the degree of improvement being slightly different due to the functionalization of the PU matrix. The mechanical properties of MWNTs-COOH-PPA / PU composite are the best. When the content of carbon nanotubes is 0.3%, the tensile strength of MWNTs-COOH-PPA / PU composites increases by 104% MWNTs-COOH / PU is equivalent, better than pure PU, but lower than MWNT8-NH2 / PU and MWNTs-PPA / PU.