Electro curing of oriented bismaleimide between aligned carbon nanotubes for high mechanical and thermal performances

Aligned assembly of carbon nanotubes (CNTs) is the key for high mechanical, electrical and thermal properties for CNT fibers. To overcome the weak van der Waals interactions between the CNTs, thermosetting polymers can be introduced into the fibers because efficient strengthening can be realized after a thermal curing. Here a better curing strategy, namely electro curing, is applied to bismaleimide (BMI)-impregnated CNT fibers to improve the inter-tube thermal transport. As the electric current is conducting along the CNT surface and induces the strongest Joule heating right there, the aromatic BMI resins can be cured into an oriented structure. Under the optimal curing current whose Joule heating is strong without inducing the BMI degradation, the fiber's intrinsic thermal conductivity can be improved from 30 to 177 Wm−1K−1, and the apparent conductivity can be up to 374 Wm−1K−1at a sample length of 12 mm. The effect of thermal radiation is also semi-quantitatively studied by estimating the real surface area that radiates heat in the 3ω method.