硅烷化多壁碳纳米管/硅橡胶复合材料的制备和介电性能

The surface modification of multi-walled carbon nanotubes (MWCNTs) was carried out with three silane coupling agents with different functionalities (methyltriethoxysilane (MTES), dimethyldiethoxysilane (DMDES) and trimethylethoxysilane (TMES)) under the condition of the presence of water. The chemical structures of MWCNTs before and after modification were characterized by FTIR, XPS, TG and SEM. The MWCNTs/silicone rubber (SR) composites were prepared by mechanical blending method. The SEM results showed that when MWCNTs, MWCNTs - MTES, MWCNTs - DMDES and MWCNTs - TMES with different mass fractions were filled into SR, the silane modification could reduce the interaction between MWCNTs and improve their dispersibility in SR. The results of tensile tests showed that the interaction between the modified MWCNTs and SR was enhanced and the compatibility between the two was improved. When the content of the modified MWCNTs was ≤ 2wt%, the elastic modulus of the MWCNTs/SR composites had no obvious change. The results of dielectric property tests showed that when the mass fraction of MWCNTs - MTES was 2wt%, the dielectric constant of the MWCNTs - MTES/SR composites reached 5.02 at 104 Hz, which was 57% higher than that of the pure silicone rubber, while the dielectric loss was still lower than 0.01 and remained at a very low level.

采用三种不同官能度的硅烷偶联剂(甲基三乙氧基硅烷(MTES)、二甲基二乙氧基硅烷(DMDES)及三甲基乙氧基硅烷(TMES))在有水条件下对多壁碳纳米管(MWCNTs)进行表面改性,通过FTIR、XPS、TG及SEM表征了MWCNTs改性前和改性后的化学结构。采用机械共混法制备了MWCNTs/硅橡胶(SR)复合材料。SEM结果表明,将不同质量分数的MWCNTs、MWCNTs-MTES、MWCNTs-DMDES和MWCNTs-TMES填充到SR中,硅烷改性可以降低MWCNTs间的相互作用,改善其在SR中的分散性。拉伸试验结果表明,改性MWCNTs与SR之间的相互作用增强,二者的相容性得到改善。当改性MWCNTs含量≤2wt%时,MWCNTs/SR复合材料的弹性模量无明显变化。介电性能测试结果表明,当MWCNTs-MTES质量分数为2wt%时,MWCNTs-MTES/SR复合材料在104 Hz时介电常数达到5.02,较纯硅橡胶提高了57%,而介电损耗仍低于0.01,保持在极低水平。