混杂功能化碳纳米管/聚氨酯复合材料的制备及性能

Preparation and Properties of Hybrid Functionalized Carbon Nanotube Polyurethane Composites

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。

Multi-walled carbon nanotubes （MWNTs） were modified with different approaches to produce carboxylated carbon nanotubes （MWNTs-COOH）, covalently functionalized carbon nanotubes （MWNTs-NH2）, noncovalently functionalized carbon nanotubes （MWNTs-PPA）, and hybrid function- alized carbon nanotubes （MWNTs-COOH-PPA）, respectively. These functionalized MWNTs were re- spectively incorporated into polyurethane （PU） with various mass fraction to prepare four kinds of PU composite. The mechanical and thermal properties of these composites were tested by means of universal testing： machine and thermal gravimetric analyzer. The results show that by grafting few functional groupsonto the MWNT surface to prevent the detachment of noncovalent wrapping, hybrid tunctionalization not only improves the dispersion of MWNTs in the matrix, but also retains the interfacial interactions between them. Therefore the best reinforcement is achieved. Addition of heat-resistant MWNTs increases the thermal deposition temperature of PU matrix, and the increase amount slightly varies with functional- ization approaches. MWNTs-COOH-PPA/PU has the best mechanical performance. Its tensile strength increased 104% compared with pure PU at 0.3% MWNTs loading. Its thermal decomposition temper- ature is identical to that of MWNTs-COOH/PU, better than that of pure PU, but lower than that of MWNTs-NH2/PU and MWNTs-PPA/PU.