In situ preparation of polyimide/amino-functionalized carbon nanotube composites and their properties

In order to improve the dispersion of carbon nanotubes (CNTs) in polyimide (PI) matrix and the interfacial interaction between CNTs and PI, 4,4′-diaminodiphenyl ether (ODA)-functionalized carbon nanotubes (CNTs-ODA) were synthesized by oxidation and amidation reactions. The structures and morphologies of CNTs-ODA were characterized using Fourier transform infrared spectrometer, transmission electron microscopy, and thermal gravimetric analysis. Then a series of polyimide/amino-functionalized carbon nanotube (PI/CNTODA) nanocomposites were prepared by in situ polymerization. CNTs-ODA were homogeneously dispersed in PI matrix. The influence of CNT-ODA content on mechanical properties of PI/CNT-ODA nanocomposites was investigated. It was found that the mechanical properties of nanocomposites were enhanced with the increase in CNT-ODA loading. When the content of CNTs-ODA was 3 wt%, the tensile strength of PI/CNTODA nanocomposites was up to 169.07 MPa (87.11% higher than that of neat PI). The modulus of PI/CNTs-ODA was increased by 62.64%, while elongation at break was increased by 66.05%. The improvement of the mechanical properties of PI/CNT-ODA nanocomposites were due to the strong chemical bond and interfacial interaction between CNTs-ODA and PI matrix.