In-situ polymerisation of carbon nanotubes/blended polyimide composites for flexible thermal conductive special-shaped structures

Cutting-edge applications put forward higher requirements for the comprehensive performance of polyimide (PI). In this study, a simple blending method was used to regulate the properties of blended PI (BPI) films, and 3-aminopropyltriethoxysilane grafted multi-walled carbon nanotube modified BPIs (MWCNT_APS_BPIs) were prepared by in-situ strategy. The resultant BPI films had excellent mechanical property, thermal stability and corrosion resistance. The tensile strength and breaking elongation were up to 163.5 MPa and 31.6%, the 5% mass-loss temperature (T_5%) was up to 577.1 °C, and the glass-transition temperature (T_g) was up to 353.4 °C. The resultant MWCNT_APS_BPI exhibited good thermal conductivity and flexibility. The highest in-plane and out-of-plane thermal conductivities of the MWCNT_APS_BPI were 1.151 and 0.763 W/mK, which were 106.22% and 45.51% higher than those of the pure BPI. The designable lightweight flexible structure prepared by MWCNT_APS_BPI is expected to be applied to heat sinks with complex structures.